Commit Graph

19421 Commits

Author SHA1 Message Date
David Hildenbrand
cc647e05db mm/userfaultfd: fix uffd-wp handling for THP migration entries
commit 24bf08c4376be417f16ceb609188b16f461b0443 upstream.

Looks like what we fixed for hugetlb in commit 44f86392bdd1 ("mm/hugetlb:
fix uffd-wp handling for migration entries in
hugetlb_change_protection()") similarly applies to THP.

Setting/clearing uffd-wp on THP migration entries is not implemented
properly.  Further, while removing migration PMDs considers the uffd-wp
bit, inserting migration PMDs does not consider the uffd-wp bit.

We have to set/clear independently of the migration entry type in
change_huge_pmd() and properly copy the uffd-wp bit in
set_pmd_migration_entry().

Verified using a simple reproducer that triggers migration of a THP, that
the set_pmd_migration_entry() no longer loses the uffd-wp bit.

Link: https://lkml.kernel.org/r/20230405160236.587705-2-david@redhat.com
Fixes: f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26 14:28:40 +02:00
Baokun Li
3e6bd2653f writeback, cgroup: fix null-ptr-deref write in bdi_split_work_to_wbs
commit 1ba1199ec5747f475538c0d25a32804e5ba1dfde upstream.

KASAN report null-ptr-deref:
==================================================================
BUG: KASAN: null-ptr-deref in bdi_split_work_to_wbs+0x5c5/0x7b0
Write of size 8 at addr 0000000000000000 by task sync/943
CPU: 5 PID: 943 Comm: sync Tainted: 6.3.0-rc5-next-20230406-dirty #461
Call Trace:
 <TASK>
 dump_stack_lvl+0x7f/0xc0
 print_report+0x2ba/0x340
 kasan_report+0xc4/0x120
 kasan_check_range+0x1b7/0x2e0
 __kasan_check_write+0x24/0x40
 bdi_split_work_to_wbs+0x5c5/0x7b0
 sync_inodes_sb+0x195/0x630
 sync_inodes_one_sb+0x3a/0x50
 iterate_supers+0x106/0x1b0
 ksys_sync+0x98/0x160
[...]
==================================================================

The race that causes the above issue is as follows:

           cpu1                     cpu2
-------------------------|-------------------------
inode_switch_wbs
 INIT_WORK(&isw->work, inode_switch_wbs_work_fn)
 queue_rcu_work(isw_wq, &isw->work)
 // queue_work async
  inode_switch_wbs_work_fn
   wb_put_many(old_wb, nr_switched)
    percpu_ref_put_many
     ref->data->release(ref)
     cgwb_release
      queue_work(cgwb_release_wq, &wb->release_work)
      // queue_work async
       &wb->release_work
       cgwb_release_workfn
                            ksys_sync
                             iterate_supers
                              sync_inodes_one_sb
                               sync_inodes_sb
                                bdi_split_work_to_wbs
                                 kmalloc(sizeof(*work), GFP_ATOMIC)
                                 // alloc memory failed
        percpu_ref_exit
         ref->data = NULL
         kfree(data)
                                 wb_get(wb)
                                  percpu_ref_get(&wb->refcnt)
                                   percpu_ref_get_many(ref, 1)
                                    atomic_long_add(nr, &ref->data->count)
                                     atomic64_add(i, v)
                                     // trigger null-ptr-deref

bdi_split_work_to_wbs() traverses &bdi->wb_list to split work into all
wbs.  If the allocation of new work fails, the on-stack fallback will be
used and the reference count of the current wb is increased afterwards.
If cgroup writeback membership switches occur before getting the reference
count and the current wb is released as old_wd, then calling wb_get() or
wb_put() will trigger the null pointer dereference above.

This issue was introduced in v4.3-rc7 (see fix tag1).  Both
sync_inodes_sb() and __writeback_inodes_sb_nr() calls to
bdi_split_work_to_wbs() can trigger this issue.  For scenarios called via
sync_inodes_sb(), originally commit 7fc5854f8c ("writeback: synchronize
sync(2) against cgroup writeback membership switches") reduced the
possibility of the issue by adding wb_switch_rwsem, but in v5.14-rc1 (see
fix tag2) removed the "inode_io_list_del_locked(inode, old_wb)" from
inode_switch_wbs_work_fn() so that wb->state contains WB_has_dirty_io,
thus old_wb is not skipped when traversing wbs in bdi_split_work_to_wbs(),
and the issue becomes easily reproducible again.

To solve this problem, percpu_ref_exit() is called under RCU protection to
avoid race between cgwb_release_workfn() and bdi_split_work_to_wbs().
Moreover, replace wb_get() with wb_tryget() in bdi_split_work_to_wbs(),
and skip the current wb if wb_tryget() fails because the wb has already
been shutdown.

Link: https://lkml.kernel.org/r/20230410130826.1492525-1-libaokun1@huawei.com
Fixes: b817525a4a ("writeback: bdi_writeback iteration must not skip dying ones")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Hou Tao <houtao1@huawei.com>
Cc: yangerkun <yangerkun@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-26 14:28:39 +02:00
Liam R. Howlett
1c87a6f82a mm: enable maple tree RCU mode by default.
commit 3dd4432549415f3c65dd52d5c687629efbf4ece1 upstream.

Use the maple tree in RCU mode for VMA tracking.

The maple tree tracks the stack and is able to update the pivot
(lower/upper boundary) in-place to allow the page fault handler to write
to the tree while holding just the mmap read lock.  This is safe as the
writes to the stack have a guard VMA which ensures there will always be
a NULL in the direction of the growth and thus will only update a pivot.

It is possible, but not recommended, to have VMAs that grow up/down
without guard VMAs.  syzbot has constructed a testcase which sets up a
VMA to grow and consume the empty space.  Overwriting the entire NULL
entry causes the tree to be altered in a way that is not safe for
concurrent readers; the readers may see a node being rewritten or one
that does not match the maple state they are using.

Enabling RCU mode allows the concurrent readers to see a stable node and
will return the expected result.

Link: https://lkml.kernel.org/r/20230227173632.3292573-9-surenb@google.com
Cc: stable@vger.kernel.org
Fixes: d4af56c5c7 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: syzbot+8d95422d3537159ca390@syzkaller.appspotmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13 16:55:40 +02:00
Alistair Popple
0b73b8ac30 mm: take a page reference when removing device exclusive entries
commit 7c7b962938ddda6a9cd095de557ee5250706ea88 upstream.

Device exclusive page table entries are used to prevent CPU access to a
page whilst it is being accessed from a device.  Typically this is used to
implement atomic operations when the underlying bus does not support
atomic access.  When a CPU thread encounters a device exclusive entry it
locks the page and restores the original entry after calling mmu notifiers
to signal drivers that exclusive access is no longer available.

The device exclusive entry holds a reference to the page making it safe to
access the struct page whilst the entry is present.  However the fault
handling code does not hold the PTL when taking the page lock.  This means
if there are multiple threads faulting concurrently on the device
exclusive entry one will remove the entry whilst others will wait on the
page lock without holding a reference.

This can lead to threads locking or waiting on a folio with a zero
refcount.  Whilst mmap_lock prevents the pages getting freed via munmap()
they may still be freed by a migration.  This leads to warnings such as
PAGE_FLAGS_CHECK_AT_FREE due to the page being locked when the refcount
drops to zero.

Fix this by trying to take a reference on the folio before locking it.
The code already checks the PTE under the PTL and aborts if the entry is
no longer there.  It is also possible the folio has been unmapped, freed
and re-allocated allowing a reference to be taken on an unrelated folio.
This case is also detected by the PTE check and the folio is unlocked
without further changes.

Link: https://lkml.kernel.org/r/20230330012519.804116-1-apopple@nvidia.com
Fixes: b756a3b5e7 ("mm: device exclusive memory access")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13 16:55:38 +02:00
Peter Xu
f042ee354c mm/hugetlb: fix uffd wr-protection for CoW optimization path
commit 60d5b473d61be61ac315e544fcd6a8234a79500e upstream.

This patch fixes an issue that a hugetlb uffd-wr-protected mapping can be
writable even with uffd-wp bit set.  It only happens with hugetlb private
mappings, when someone firstly wr-protects a missing pte (which will
install a pte marker), then a write to the same page without any prior
access to the page.

Userfaultfd-wp trap for hugetlb was implemented in hugetlb_fault() before
reaching hugetlb_wp() to avoid taking more locks that userfault won't
need.  However there's one CoW optimization path that can trigger
hugetlb_wp() inside hugetlb_no_page(), which will bypass the trap.

This patch skips hugetlb_wp() for CoW and retries the fault if uffd-wp bit
is detected.  The new path will only trigger in the CoW optimization path
because generic hugetlb_fault() (e.g.  when a present pte was
wr-protected) will resolve the uffd-wp bit already.  Also make sure
anonymous UNSHARE won't be affected and can still be resolved, IOW only
skip CoW not CoR.

This patch will be needed for v5.19+ hence copy stable.

[peterx@redhat.com: v2]
  Link: https://lkml.kernel.org/r/ZBzOqwF2wrHgBVZb@x1n
[peterx@redhat.com: v3]
  Link: https://lkml.kernel.org/r/20230324142620.2344140-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20230321191840.1897940-1-peterx@redhat.com
Fixes: 166f3ecc0d ("mm/hugetlb: hook page faults for uffd write protection")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13 16:55:36 +02:00
Rongwei Wang
85cc118ce6 mm/swap: fix swap_info_struct race between swapoff and get_swap_pages()
commit 6fe7d6b992113719e96744d974212df3fcddc76c upstream.

The si->lock must be held when deleting the si from the available list.
Otherwise, another thread can re-add the si to the available list, which
can lead to memory corruption.  The only place we have found where this
happens is in the swapoff path.  This case can be described as below:

core 0                       core 1
swapoff

del_from_avail_list(si)      waiting

try lock si->lock            acquire swap_avail_lock
                             and re-add si into
                             swap_avail_head

acquire si->lock but missing si already being added again, and continuing
to clear SWP_WRITEOK, etc.

It can be easily found that a massive warning messages can be triggered
inside get_swap_pages() by some special cases, for example, we call
madvise(MADV_PAGEOUT) on blocks of touched memory concurrently, meanwhile,
run much swapon-swapoff operations (e.g.  stress-ng-swap).

However, in the worst case, panic can be caused by the above scene.  In
swapoff(), the memory used by si could be kept in swap_info[] after
turning off a swap.  This means memory corruption will not be caused
immediately until allocated and reset for a new swap in the swapon path.
A panic message caused: (with CONFIG_PLIST_DEBUG enabled)

------------[ cut here ]------------
top: 00000000e58a3003, n: 0000000013e75cda, p: 000000008cd4451a
prev: 0000000035b1e58a, n: 000000008cd4451a, p: 000000002150ee8d
next: 000000008cd4451a, n: 000000008cd4451a, p: 000000008cd4451a
WARNING: CPU: 21 PID: 1843 at lib/plist.c:60 plist_check_prev_next_node+0x50/0x70
Modules linked in: rfkill(E) crct10dif_ce(E)...
CPU: 21 PID: 1843 Comm: stress-ng Kdump: ... 5.10.134+
Hardware name: Alibaba Cloud ECS, BIOS 0.0.0 02/06/2015
pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
pc : plist_check_prev_next_node+0x50/0x70
lr : plist_check_prev_next_node+0x50/0x70
sp : ffff0018009d3c30
x29: ffff0018009d3c40 x28: ffff800011b32a98
x27: 0000000000000000 x26: ffff001803908000
x25: ffff8000128ea088 x24: ffff800011b32a48
x23: 0000000000000028 x22: ffff001800875c00
x21: ffff800010f9e520 x20: ffff001800875c00
x19: ffff001800fdc6e0 x18: 0000000000000030
x17: 0000000000000000 x16: 0000000000000000
x15: 0736076307640766 x14: 0730073007380731
x13: 0736076307640766 x12: 0730073007380731
x11: 000000000004058d x10: 0000000085a85b76
x9 : ffff8000101436e4 x8 : ffff800011c8ce08
x7 : 0000000000000000 x6 : 0000000000000001
x5 : ffff0017df9ed338 x4 : 0000000000000001
x3 : ffff8017ce62a000 x2 : ffff0017df9ed340
x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 plist_check_prev_next_node+0x50/0x70
 plist_check_head+0x80/0xf0
 plist_add+0x28/0x140
 add_to_avail_list+0x9c/0xf0
 _enable_swap_info+0x78/0xb4
 __do_sys_swapon+0x918/0xa10
 __arm64_sys_swapon+0x20/0x30
 el0_svc_common+0x8c/0x220
 do_el0_svc+0x2c/0x90
 el0_svc+0x1c/0x30
 el0_sync_handler+0xa8/0xb0
 el0_sync+0x148/0x180
irq event stamp: 2082270

Now, si->lock locked before calling 'del_from_avail_list()' to make sure
other thread see the si had been deleted and SWP_WRITEOK cleared together,
will not reinsert again.

This problem exists in versions after stable 5.10.y.

Link: https://lkml.kernel.org/r/20230404154716.23058-1-rongwei.wang@linux.alibaba.com
Fixes: a2468cc9bf ("swap: choose swap device according to numa node")
Tested-by: Yongchen Yin <wb-yyc939293@alibaba-inc.com>
Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13 16:55:36 +02:00
Yafang Shao
ef6bd8f64c mm: vmalloc: avoid warn_alloc noise caused by fatal signal
commit f349b15e183d6956f1b63d6ff57849ff10c7edd5 upstream.

There're some suspicious warn_alloc on my test serer, for example,

[13366.518837] warn_alloc: 81 callbacks suppressed
[13366.518841] test_verifier: vmalloc error: size 4096, page order 0, failed to allocate pages, mode:0x500dc2(GFP_HIGHUSER|__GFP_ZERO|__GFP_ACCOUNT), nodemask=(null),cpuset=/,mems_allowed=0-1
[13366.522240] CPU: 30 PID: 722463 Comm: test_verifier Kdump: loaded Tainted: G        W  O       6.2.0+ #638
[13366.524216] Call Trace:
[13366.524702]  <TASK>
[13366.525148]  dump_stack_lvl+0x6c/0x80
[13366.525712]  dump_stack+0x10/0x20
[13366.526239]  warn_alloc+0x119/0x190
[13366.526783]  ? alloc_pages_bulk_array_mempolicy+0x9e/0x2a0
[13366.527470]  __vmalloc_area_node+0x546/0x5b0
[13366.528066]  __vmalloc_node_range+0xc2/0x210
[13366.528660]  __vmalloc_node+0x42/0x50
[13366.529186]  ? bpf_prog_realloc+0x53/0xc0
[13366.529743]  __vmalloc+0x1e/0x30
[13366.530235]  bpf_prog_realloc+0x53/0xc0
[13366.530771]  bpf_patch_insn_single+0x80/0x1b0
[13366.531351]  bpf_jit_blind_constants+0xe9/0x1c0
[13366.531932]  ? __free_pages+0xee/0x100
[13366.532457]  ? free_large_kmalloc+0x58/0xb0
[13366.533002]  bpf_int_jit_compile+0x8c/0x5e0
[13366.533546]  bpf_prog_select_runtime+0xb4/0x100
[13366.534108]  bpf_prog_load+0x6b1/0xa50
[13366.534610]  ? perf_event_task_tick+0x96/0xb0
[13366.535151]  ? security_capable+0x3a/0x60
[13366.535663]  __sys_bpf+0xb38/0x2190
[13366.536120]  ? kvm_clock_get_cycles+0x9/0x10
[13366.536643]  __x64_sys_bpf+0x1c/0x30
[13366.537094]  do_syscall_64+0x38/0x90
[13366.537554]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
[13366.538107] RIP: 0033:0x7f78310f8e29
[13366.538561] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 17 e0 2c 00 f7 d8 64 89 01 48
[13366.540286] RSP: 002b:00007ffe2a61fff8 EFLAGS: 00000206 ORIG_RAX: 0000000000000141
[13366.541031] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f78310f8e29
[13366.541749] RDX: 0000000000000080 RSI: 00007ffe2a6200b0 RDI: 0000000000000005
[13366.542470] RBP: 00007ffe2a620010 R08: 00007ffe2a6202a0 R09: 00007ffe2a6200b0
[13366.543183] R10: 00000000000f423e R11: 0000000000000206 R12: 0000000000407800
[13366.543900] R13: 00007ffe2a620540 R14: 0000000000000000 R15: 0000000000000000
[13366.544623]  </TASK>
[13366.545260] Mem-Info:
[13366.546121] active_anon:81319 inactive_anon:20733 isolated_anon:0
 active_file:69450 inactive_file:5624 isolated_file:0
 unevictable:0 dirty:10 writeback:0
 slab_reclaimable:69649 slab_unreclaimable:48930
 mapped:27400 shmem:12868 pagetables:4929
 sec_pagetables:0 bounce:0
 kernel_misc_reclaimable:0
 free:15870308 free_pcp:142935 free_cma:0
[13366.551886] Node 0 active_anon:224836kB inactive_anon:33528kB active_file:175692kB inactive_file:13752kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:59248kB dirty:32kB writeback:0kB shmem:18252kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:4616kB pagetables:10664kB sec_pagetables:0kB all_unreclaimable? no
[13366.555184] Node 1 active_anon:100440kB inactive_anon:49404kB active_file:102108kB inactive_file:8744kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:50352kB dirty:8kB writeback:0kB shmem:33220kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:3896kB pagetables:9052kB sec_pagetables:0kB all_unreclaimable? no
[13366.558262] Node 0 DMA free:15360kB boost:0kB min:304kB low:380kB high:456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[13366.560821] lowmem_reserve[]: 0 2735 31873 31873 31873
[13366.561981] Node 0 DMA32 free:2790904kB boost:0kB min:56028kB low:70032kB high:84036kB reserved_highatomic:0KB active_anon:1936kB inactive_anon:20kB active_file:396kB inactive_file:344kB unevictable:0kB writepending:0kB present:3129200kB managed:2801520kB mlocked:0kB bounce:0kB free_pcp:5188kB local_pcp:0kB free_cma:0kB
[13366.565148] lowmem_reserve[]: 0 0 29137 29137 29137
[13366.566168] Node 0 Normal free:28533824kB boost:0kB min:596740kB low:745924kB high:895108kB reserved_highatomic:28672KB active_anon:222900kB inactive_anon:33508kB active_file:175296kB inactive_file:13408kB unevictable:0kB writepending:32kB present:30408704kB managed:29837172kB mlocked:0kB bounce:0kB free_pcp:295724kB local_pcp:0kB free_cma:0kB
[13366.569485] lowmem_reserve[]: 0 0 0 0 0
[13366.570416] Node 1 Normal free:32141144kB boost:0kB min:660504kB low:825628kB high:990752kB reserved_highatomic:69632KB active_anon:100440kB inactive_anon:49404kB active_file:102108kB inactive_file:8744kB unevictable:0kB writepending:8kB present:33554432kB managed:33025372kB mlocked:0kB bounce:0kB free_pcp:270880kB local_pcp:46860kB free_cma:0kB
[13366.573403] lowmem_reserve[]: 0 0 0 0 0
[13366.574015] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15360kB
[13366.575474] Node 0 DMA32: 782*4kB (UME) 756*8kB (UME) 736*16kB (UME) 745*32kB (UME) 694*64kB (UME) 653*128kB (UME) 595*256kB (UME) 552*512kB (UME) 454*1024kB (UME) 347*2048kB (UME) 246*4096kB (UME) = 2790904kB
[13366.577442] Node 0 Normal: 33856*4kB (UMEH) 51815*8kB (UMEH) 42418*16kB (UMEH) 36272*32kB (UMEH) 22195*64kB (UMEH) 10296*128kB (UMEH) 7238*256kB (UMEH) 5638*512kB (UEH) 5337*1024kB (UMEH) 3506*2048kB (UMEH) 1470*4096kB (UME) = 28533784kB
[13366.580460] Node 1 Normal: 15776*4kB (UMEH) 37485*8kB (UMEH) 29509*16kB (UMEH) 21420*32kB (UMEH) 14818*64kB (UMEH) 13051*128kB (UMEH) 9918*256kB (UMEH) 7374*512kB (UMEH) 5397*1024kB (UMEH) 3887*2048kB (UMEH) 2002*4096kB (UME) = 32141240kB
[13366.583027] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
[13366.584380] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[13366.585702] Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
[13366.587042] Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[13366.588372] 87386 total pagecache pages
[13366.589266] 0 pages in swap cache
[13366.590327] Free swap  = 0kB
[13366.591227] Total swap = 0kB
[13366.592142] 16777082 pages RAM
[13366.593057] 0 pages HighMem/MovableOnly
[13366.594037] 357226 pages reserved
[13366.594979] 0 pages hwpoisoned

This failure really confuse me as there're still lots of available pages.
Finally I figured out it was caused by a fatal signal.  When a process is
allocating memory via vm_area_alloc_pages(), it will break directly even
if it hasn't allocated the requested pages when it receives a fatal
signal.  In that case, we shouldn't show this warn_alloc, as it is
useless.  We only need to show this warning when there're really no enough
pages.

Link: https://lkml.kernel.org/r/20230330162625.13604-1-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13 16:55:35 +02:00
Muchun Song
54df8e39ce mm: kfence: fix handling discontiguous page
commit 1f2803b2660f4b04d48d065072c0ae0c9ca255fd upstream.

The struct pages could be discontiguous when the kfence pool is allocated
via alloc_contig_pages() with CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP.

This may result in setting PG_slab and memcg_data to a arbitrary
address (may be not used as a struct page), which in the worst case
might corrupt the kernel.

So the iteration should use nth_page().

Link: https://lkml.kernel.org/r/20230323025003.94447-1-songmuchun@bytedance.com
Fixes: 0ce20dd840 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13 16:55:30 +02:00
Muchun Song
476699a8a7 mm: kfence: fix PG_slab and memcg_data clearing
commit 3ee2d7471fa4963a2ced0a84f0653ce88b43c5b2 upstream.

It does not reset PG_slab and memcg_data when KFENCE fails to initialize
kfence pool at runtime.  It is reporting a "Bad page state" message when
kfence pool is freed to buddy.  The checking of whether it is a compound
head page seems unnecessary since we already guarantee this when
allocating kfence pool.   Remove the check to simplify the code.

Link: https://lkml.kernel.org/r/20230320030059.20189-1-songmuchun@bytedance.com
Fixes: 0ce20dd840 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13 16:55:30 +02:00
Liam R. Howlett
286b0cab31 mm/ksm: fix race with VMA iteration and mm_struct teardown
commit 6db504ce55bdbc575723938fc480713c9183f6a2 upstream.

exit_mmap() will tear down the VMAs and maple tree with the mmap_lock held
in write mode.  Ensure that the maple tree is still valid by checking
ksm_test_exit() after taking the mmap_lock in read mode, but before the
for_each_vma() iterator dereferences a destroyed maple tree.

Since the maple tree is destroyed, the flags telling lockdep to check an
external lock has been cleared.  Skip the for_each_vma() iterator to avoid
dereferencing a maple tree without the external lock flag, which would
create a lockdep warning.

Link: https://lkml.kernel.org/r/20230308220310.3119196-1-Liam.Howlett@oracle.com
Fixes: a5f18ba072 ("mm/ksm: use vma iterators instead of vma linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
  Link: https://lore.kernel.org/lkml/ZAdUUhSbaa6fHS36@xpf.sh.intel.com/
Reported-by: syzbot+2ee18845e89ae76342c5@syzkaller.appspotmail.com
  Link: https://syzkaller.appspot.com/bug?id=64a3e95957cd3deab99df7cd7b5a9475af92c93e
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <heng.su@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:29 +02:00
Peter Collingbourne
450317033f Revert "kasan: drop skip_kasan_poison variable in free_pages_prepare"
commit f446883d12b8bfa486f7c98d403054d61d38c989 upstream.

This reverts commit 487a32ec24.

should_skip_kasan_poison() reads the PG_skip_kasan_poison flag from
page->flags.  However, this line of code in free_pages_prepare():

	page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;

clears most of page->flags, including PG_skip_kasan_poison, before calling
should_skip_kasan_poison(), which meant that it would never return true as
a result of the page flag being set.  Therefore, fix the code to call
should_skip_kasan_poison() before clearing the flags, as we were doing
before the reverted patch.

This fixes a measurable performance regression introduced in the reverted
commit, where munmap() takes longer than intended if HW tags KASAN is
supported and enabled at runtime.  Without this patch, we see a
single-digit percentage performance regression in a particular
mmap()-heavy benchmark when enabling HW tags KASAN, and with the patch,
there is no statistically significant performance impact when enabling HW
tags KASAN.

Link: https://lkml.kernel.org/r/20230310042914.3805818-2-pcc@google.com
Fixes: 487a32ec24 ("kasan: drop skip_kasan_poison variable in free_pages_prepare")
  Link: https://linux-review.googlesource.com/id/Ic4f13affeebd20548758438bb9ed9ca40e312b79
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>	[6.1]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:26 +02:00
Marco Elver
1c00030a59 kfence: avoid passing -g for test
commit 2e08ca1802441224f5b7cc6bffbb687f7406de95 upstream.

Nathan reported that when building with GNU as and a version of clang that
defaults to DWARF5:

  $ make -skj"$(nproc)" ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- \
			LLVM=1 LLVM_IAS=0 O=build \
			mrproper allmodconfig mm/kfence/kfence_test.o
  /tmp/kfence_test-08a0a0.s: Assembler messages:
  /tmp/kfence_test-08a0a0.s:14627: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14628: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14632: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14633: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14639: Error: non-constant .uleb128 is not supported
  ...

This is because `-g` defaults to the compiler debug info default.  If the
assembler does not support some of the directives used, the above errors
occur.  To fix, remove the explicit passing of `-g`.

All the test wants is that stack traces print valid function names, and
debug info is not required for that.  (I currently cannot recall why I
added the explicit `-g`.)

Link: https://lkml.kernel.org/r/20230316224705.709984-1-elver@google.com
Fixes: bc8fbc5f30 ("kfence: add test suite")
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:25 +02:00
Muchun Song
f2a4304e9f mm: kfence: fix using kfence_metadata without initialization in show_object()
commit 1c86a188e03156223a34d09ce290b49bd4dd0403 upstream.

The variable kfence_metadata is initialized in kfence_init_pool(), then,
it is not initialized if kfence is disabled after booting.  In this case,
kfence_metadata will be used (e.g.  ->lock and ->state fields) without
initialization when reading /sys/kernel/debug/kfence/objects.  There will
be a warning if you enable CONFIG_DEBUG_SPINLOCK.  Fix it by creating
debugfs files when necessary.

Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com
Fixes: 0ce20dd840 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Tested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:25 +02:00
Geert Uytterhoeven
f311869d72 mm/slab: Fix undefined init_cache_node_node() for NUMA and !SMP
commit 66a1c22b709178e7b823d44465d0c2e5ed7492fb upstream.

sh/migor_defconfig:

    mm/slab.c: In function ‘slab_memory_callback’:
    mm/slab.c:1127:23: error: implicit declaration of function ‘init_cache_node_node’; did you mean ‘drain_cache_node_node’? [-Werror=implicit-function-declaration]
     1127 |                 ret = init_cache_node_node(nid);
	  |                       ^~~~~~~~~~~~~~~~~~~~
	  |                       drain_cache_node_node

The #ifdef condition protecting the definition of init_cache_node_node()
no longer matches the conditions protecting the (multiple) users.

Fix this by syncing the conditions.

Fixes: 76af6a054d ("mm/migrate: add CPU hotplug to demotion #ifdef")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/b5bdea22-ed2f-3187-6efe-0c72330270a4@infradead.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:23 +02:00
James Houghton
aff80fb99b mm: teach mincore_hugetlb about pte markers
commit 63cf584203f3367c8b073d417c8e5cbbfc450506 upstream.

By checking huge_pte_none(), we incorrectly classify PTE markers as
"present".  Instead, check huge_pte_none_mostly(), classifying PTE markers
the same as if the PTE were completely blank.

PTE markers, unlike other kinds of swap entries, don't reference any
physical page and don't indicate that a physical page was mapped
previously.  As such, treat them as non-present for the sake of mincore().

Link: https://lkml.kernel.org/r/20230302222404.175303-1-jthoughton@google.com
Fixes: 5c041f5d1f ("mm: teach core mm about pte markers")
Signed-off-by: James Houghton <jthoughton@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-22 13:34:03 +01:00
David Hildenbrand
b8388048b5 mm/userfaultfd: propagate uffd-wp bit when PTE-mapping the huge zeropage
commit 42b2af2c9b7eede8ef21d0943f84d135e21a32a3 upstream.

Currently, we'd lose the userfaultfd-wp marker when PTE-mapping a huge
zeropage, resulting in the next write faults in the PMD range not
triggering uffd-wp events.

Various actions (partial MADV_DONTNEED, partial mremap, partial munmap,
partial mprotect) could trigger this.  However, most importantly,
un-protecting a single sub-page from the userfaultfd-wp handler when
processing a uffd-wp event will PTE-map the shared huge zeropage and lose
the uffd-wp bit for the remainder of the PMD.

Let's properly propagate the uffd-wp bit to the PMDs.

 #define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <inttypes.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
 #include <poll.h>
 #include <pthread.h>
 #include <sys/mman.h>
 #include <sys/syscall.h>
 #include <sys/ioctl.h>
 #include <linux/userfaultfd.h>

 static size_t pagesize;
 static int uffd;
 static volatile bool uffd_triggered;

 #define barrier() __asm__ __volatile__("": : :"memory")

 static void uffd_wp_range(char *start, size_t size, bool wp)
 {
 	struct uffdio_writeprotect uffd_writeprotect;

 	uffd_writeprotect.range.start = (unsigned long) start;
 	uffd_writeprotect.range.len = size;
 	if (wp) {
 		uffd_writeprotect.mode = UFFDIO_WRITEPROTECT_MODE_WP;
 	} else {
 		uffd_writeprotect.mode = 0;
 	}
 	if (ioctl(uffd, UFFDIO_WRITEPROTECT, &uffd_writeprotect)) {
 		fprintf(stderr, "UFFDIO_WRITEPROTECT failed: %d\n", errno);
 		exit(1);
 	}
 }

 static void *uffd_thread_fn(void *arg)
 {
 	static struct uffd_msg msg;
 	ssize_t nread;

 	while (1) {
 		struct pollfd pollfd;
 		int nready;

 		pollfd.fd = uffd;
 		pollfd.events = POLLIN;
 		nready = poll(&pollfd, 1, -1);
 		if (nready == -1) {
 			fprintf(stderr, "poll() failed: %d\n", errno);
 			exit(1);
 		}

 		nread = read(uffd, &msg, sizeof(msg));
 		if (nread <= 0)
 			continue;

 		if (msg.event != UFFD_EVENT_PAGEFAULT ||
 		    !(msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP)) {
 			printf("FAIL: wrong uffd-wp event fired\n");
 			exit(1);
 		}

 		/* un-protect the single page. */
 		uffd_triggered = true;
 		uffd_wp_range((char *)(uintptr_t)msg.arg.pagefault.address,
 			      pagesize, false);
 	}
 	return arg;
 }

 static int setup_uffd(char *map, size_t size)
 {
 	struct uffdio_api uffdio_api;
 	struct uffdio_register uffdio_register;
 	pthread_t thread;

 	uffd = syscall(__NR_userfaultfd,
 		       O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY);
 	if (uffd < 0) {
 		fprintf(stderr, "syscall() failed: %d\n", errno);
 		return -errno;
 	}

 	uffdio_api.api = UFFD_API;
 	uffdio_api.features = UFFD_FEATURE_PAGEFAULT_FLAG_WP;
 	if (ioctl(uffd, UFFDIO_API, &uffdio_api) < 0) {
 		fprintf(stderr, "UFFDIO_API failed: %d\n", errno);
 		return -errno;
 	}

 	if (!(uffdio_api.features & UFFD_FEATURE_PAGEFAULT_FLAG_WP)) {
 		fprintf(stderr, "UFFD_FEATURE_WRITEPROTECT missing\n");
 		return -ENOSYS;
 	}

 	uffdio_register.range.start = (unsigned long) map;
 	uffdio_register.range.len = size;
 	uffdio_register.mode = UFFDIO_REGISTER_MODE_WP;
 	if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) < 0) {
 		fprintf(stderr, "UFFDIO_REGISTER failed: %d\n", errno);
 		return -errno;
 	}

 	pthread_create(&thread, NULL, uffd_thread_fn, NULL);

 	return 0;
 }

 int main(void)
 {
 	const size_t size = 4 * 1024 * 1024ull;
 	char *map, *cur;

 	pagesize = getpagesize();

 	map = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
 	if (map == MAP_FAILED) {
 		fprintf(stderr, "mmap() failed\n");
 		return -errno;
 	}

 	if (madvise(map, size, MADV_HUGEPAGE)) {
 		fprintf(stderr, "MADV_HUGEPAGE failed\n");
 		return -errno;
 	}

 	if (setup_uffd(map, size))
 		return 1;

 	/* Read the whole range, populating zeropages. */
 	madvise(map, size, MADV_POPULATE_READ);

 	/* Write-protect the whole range. */
 	uffd_wp_range(map, size, true);

 	/* Make sure uffd-wp triggers on each page. */
 	for (cur = map; cur < map + size; cur += pagesize) {
 		uffd_triggered = false;

 		barrier();
 		/* Trigger a write fault. */
 		*cur = 1;
 		barrier();

 		if (!uffd_triggered) {
 			printf("FAIL: uffd-wp did not trigger\n");
 			return 1;
 		}
 	}

 	printf("PASS: uffd-wp triggered\n");
 	return 0;
 }

Link: https://lkml.kernel.org/r/20230302175423.589164-1-david@redhat.com
Fixes: e06f1e1dd4 ("userfaultfd: wp: enabled write protection in userfaultfd API")
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-22 13:34:03 +01:00
Tong Tiangen
313b18c774 memory tier: release the new_memtier in find_create_memory_tier()
commit 93419139fa14124c1c507d804f2b28866ebee28d upstream.

In find_create_memory_tier(), if failed to register device, then we should
release new_memtier from the tier list and put device instead of memtier.

Link: https://lkml.kernel.org/r/20230129040651.1329208-1-tongtiangen@huawei.com
Fixes: 9832fb8783 ("mm/demotion: expose memory tier details via sysfs")
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Guohanjun <guohanjun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:27 +01:00
Yin Fengwei
71946389a7 mm/thp: check and bail out if page in deferred queue already
commit 81e506bec9be1eceaf5a2c654e28ba5176ef48d8 upstream.

Kernel build regression with LLVM was reported here:
https://lore.kernel.org/all/Y1GCYXGtEVZbcv%2F5@dev-arch.thelio-3990X/ with
commit f35b5d7d67 ("mm: align larger anonymous mappings on THP
boundaries").  And the commit f35b5d7d67 was reverted.

It turned out the regression is related with madvise(MADV_DONTNEED)
was used by ld.lld. But with none PMD_SIZE aligned parameter len.
trace-bpfcc captured:
531607  531732  ld.lld          do_madvise.part.0 start: 0x7feca9000000, len: 0x7fb000, behavior: 0x4
531607  531793  ld.lld          do_madvise.part.0 start: 0x7fec86a00000, len: 0x7fb000, behavior: 0x4

If the underneath physical page is THP, the madvise(MADV_DONTNEED) can
trigger split_queue_lock contention raised significantly. perf showed
following data:
    14.85%     0.00%  ld.lld           [kernel.kallsyms]           [k]
       entry_SYSCALL_64_after_hwframe
           11.52%
                entry_SYSCALL_64_after_hwframe
                do_syscall_64
                __x64_sys_madvise
                do_madvise.part.0
                zap_page_range
                unmap_single_vma
                unmap_page_range
                page_remove_rmap
                deferred_split_huge_page
                __lock_text_start
                native_queued_spin_lock_slowpath

If THP can't be removed from rmap as whole THP, partial THP will be
removed from rmap by removing sub-pages from rmap.  Even the THP head page
is added to deferred queue already, the split_queue_lock will be acquired
and check whether the THP head page is in the queue already.  Thus, the
contention of split_queue_lock is raised.

Before acquire split_queue_lock, check and bail out early if the THP
head page is in the queue already. The checking without holding
split_queue_lock could race with deferred_split_scan, but it doesn't
impact the correctness here.

Test result of building kernel with ld.lld:
commit 7b5a0b664e (parent commit of f35b5d7d67):
time -f "\t%E real,\t%U user,\t%S sys" make LD=ld.lld -skj96 allmodconfig all
        6:07.99 real,   26367.77 user,  5063.35 sys

commit f35b5d7d67:
time -f "\t%E real,\t%U user,\t%S sys" make LD=ld.lld -skj96 allmodconfig all
        7:22.15 real,   26235.03 user,  12504.55 sys

commit f35b5d7d67 with the fixing patch:
time -f "\t%E real,\t%U user,\t%S sys" make LD=ld.lld -skj96 allmodconfig all
        6:08.49 real,   26520.15 user,  5047.91 sys

Link: https://lkml.kernel.org/r/20221223135207.2275317-1-fengwei.yin@intel.com
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:26 +01:00
Johannes Weiner
f65d6ee1d1 mm: memcontrol: deprecate charge moving
commit da34a8484d162585e22ed8c1e4114aa2f60e3567 upstream.

Charge moving mode in cgroup1 allows memory to follow tasks as they
migrate between cgroups.  This is, and always has been, a questionable
thing to do - for several reasons.

First, it's expensive.  Pages need to be identified, locked and isolated
from various MM operations, and reassigned, one by one.

Second, it's unreliable.  Once pages are charged to a cgroup, there isn't
always a clear owner task anymore.  Cache isn't moved at all, for example.
Mapped memory is moved - but if trylocking or isolating a page fails,
it's arbitrarily left behind.  Frequent moving between domains may leave a
task's memory scattered all over the place.

Third, it isn't really needed.  Launcher tasks can kick off workload tasks
directly in their target cgroup.  Using dedicated per-workload groups
allows fine-grained policy adjustments - no need to move tasks and their
physical pages between control domains.  The feature was never
forward-ported to cgroup2, and it hasn't been missed.

Despite it being a niche usecase, the maintenance overhead of supporting
it is enormous.  Because pages are moved while they are live and subject
to various MM operations, the synchronization rules are complicated.
There are lock_page_memcg() in MM and FS code, which non-cgroup people
don't understand.  In some cases we've been able to shift code and cgroup
API calls around such that we can rely on native locking as much as
possible.  But that's fragile, and sometimes we need to hold MM locks for
longer than we otherwise would (pte lock e.g.).

Mark the feature deprecated. Hopefully we can remove it soon.

And backport into -stable kernels so that people who develop against
earlier kernels are warned about this deprecation as early as possible.

[akpm@linux-foundation.org: fix memory.rst underlining]
Link: https://lkml.kernel.org/r/Y5COd+qXwk/S+n8N@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:26 +01:00
Naoya Horiguchi
deab8114fb mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON
commit 6da6b1d4a7df8c35770186b53ef65d388398e139 upstream.

After a memory error happens on a clean folio, a process unexpectedly
receives SIGBUS when it accesses the error page.  This SIGBUS killing is
pointless and simply degrades the level of RAS of the system, because the
clean folio can be dropped without any data lost on memory error handling
as we do for a clean pagecache.

When memory_failure() is called on a clean folio, try_to_unmap() is called
twice (one from split_huge_page() and one from hwpoison_user_mappings()).
The root cause of the issue is that pte conversion to hwpoisoned entry is
now done in the first call of try_to_unmap() because PageHWPoison is
already set at this point, while it's actually expected to be done in the
second call.  This behavior disturbs the error handling operation like
removing pagecache, which results in the malfunction described above.

So convert TTU_IGNORE_HWPOISON into TTU_HWPOISON and set TTU_HWPOISON only
when we really intend to convert pte to hwpoison entry.  This can prevent
other callers of try_to_unmap() from accidentally converting to hwpoison
entries.

Link: https://lkml.kernel.org/r/20230221085905.1465385-1-naoya.horiguchi@linux.dev
Fixes: a42634a6c0 ("readahead: Use a folio in read_pages()")
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:25 +01:00
andrew.yang
daa5a586e4 mm/damon/paddr: fix missing folio_put()
commit 3f98c9a62c338bbe06a215c9491e6166ea39bf82 upstream.

damon_get_folio() would always increase folio _refcount and
folio_isolate_lru() would increase folio _refcount if the folio's lru flag
is set.

If an unevictable folio isolated successfully, there will be two more
_refcount.  The one from folio_isolate_lru() will be decreased in
folio_puback_lru(), but the other one from damon_get_folio() will be left
behind.  This causes a pin page.

Whatever the case, the _refcount from damon_get_folio() should be
decreased.

Link: https://lkml.kernel.org/r/20230222064223.6735-1-andrew.yang@mediatek.com
Fixes: 57223ac295 ("mm/damon/paddr: support the pageout scheme")
Signed-off-by: andrew.yang <andrew.yang@mediatek.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[5.16.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:20 +01:00
Kuan-Ying Lee
eaba8521fd mm/gup: add folio to list when folio_isolate_lru() succeed
commit aa1e6a932ca652a50a5df458399724a80459f521 upstream.

If we call folio_isolate_lru() successfully, we will get return value 0.
We need to add this folio to the movable_pages_list.

Link: https://lkml.kernel.org/r/20230131063206.28820-1-Kuan-Ying.Lee@mediatek.com
Fixes: 67e139b02d ("mm/gup.c: refactor check_and_migrate_movable_pages()")
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Andrew Yang <andrew.yang@mediatek.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:59:54 +01:00
Aaron Thompson
2578123d5b Revert "mm: Always release pages to the buddy allocator in memblock_free_late()."
commit 647037adcad00f2bab8828d3d41cd0553d41f3bd upstream.

This reverts commit 115d9d77bb0f9152c60b6e8646369fa7f6167593.

The pages being freed by memblock_free_late() have already been
initialized, but if they are in the deferred init range,
__free_one_page() might access nearby uninitialized pages when trying to
coalesce buddies. This can, for example, trigger this BUG:

  BUG: unable to handle page fault for address: ffffe964c02580c8
  RIP: 0010:__list_del_entry_valid+0x3f/0x70
   <TASK>
   __free_one_page+0x139/0x410
   __free_pages_ok+0x21d/0x450
   memblock_free_late+0x8c/0xb9
   efi_free_boot_services+0x16b/0x25c
   efi_enter_virtual_mode+0x403/0x446
   start_kernel+0x678/0x714
   secondary_startup_64_no_verify+0xd2/0xdb
   </TASK>

A proper fix will be more involved so revert this change for the time
being.

Fixes: 115d9d77bb0f ("mm: Always release pages to the buddy allocator in memblock_free_late().")
Signed-off-by: Aaron Thompson <dev@aaront.org>
Link: https://lore.kernel.org/r/20230207082151.1303-1-dev@aaront.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:59:50 +01:00
Peter Xu
54806cb751 mm/migrate: fix wrongly apply write bit after mkdirty on sparc64
commit 96a9c287e25d690fd9623b5133703b8e310fbed1 upstream.

Nick Bowler reported another sparc64 breakage after the young/dirty
persistent work for page migration (per "Link:" below).  That's after a
similar report [2].

It turns out page migration was overlooked, and it wasn't failing before
because page migration was not enabled in the initial report test
environment.

David proposed another way [2] to fix this from sparc64 side, but that
patch didn't land somehow.  Neither did I check whether there's any other
arch that has similar issues.

Let's fix it for now as simple as moving the write bit handling to be
after dirty, like what we did before.

Note: this is based on mm-unstable, because the breakage was since 6.1 and
we're at a very late stage of 6.2 (-rc8), so I assume for this specific
case we should target this at 6.3.

[1] https://lore.kernel.org/all/20221021160603.GA23307@u164.east.ru/
[2] https://lore.kernel.org/all/20221212130213.136267-1-david@redhat.com/

Link: https://lkml.kernel.org/r/20230216153059.256739-1-peterx@redhat.com
Fixes: 2e3468778d ("mm: remember young/dirty bit for page migrations")
Link: https://lore.kernel.org/all/CADyTPExpEqaJiMGoV+Z6xVgL50ZoMJg49B10LcZ=8eg19u34BA@mail.gmail.com/
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Nick Bowler <nbowler@draconx.ca>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Nick Bowler <nbowler@draconx.ca>
Cc: <regressions@lists.linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:59:49 +01:00
Qian Yingjin
d4d9bdc694 mm/filemap: fix page end in filemap_get_read_batch
commit 5956592ce337330cdff0399a6f8b6a5aea397a8e upstream.

I was running traces of the read code against an RAID storage system to
understand why read requests were being misaligned against the underlying
RAID strips.  I found that the page end offset calculation in
filemap_get_read_batch() was off by one.

When a read is submitted with end offset 1048575, then it calculates the
end page for read of 256 when it should be 255.  "last_index" is the index
of the page beyond the end of the read and it should be skipped when get a
batch of pages for read in @filemap_get_read_batch().

The below simple patch fixes the problem.  This code was introduced in
kernel 5.12.

Link: https://lkml.kernel.org/r/20230208022400.28962-1-coolqyj@163.com
Fixes: cbd59c48ae ("mm/filemap: use head pages in generic_file_buffered_read")
Signed-off-by: Qian Yingjin <qian@ddn.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:59:49 +01:00
Zach O'Keefe
fd71c8d3b0 mm/MADV_COLLAPSE: set EAGAIN on unexpected page refcount
commit ae63c898f4004bbc7d212f4adcb3bb14852c30d6 upstream.

During collapse, in a few places we check to see if a given small page has
any unaccounted references.  If the refcount on the page doesn't match our
expectations, it must be there is an unknown user concurrently interested
in the page, and so it's not safe to move the contents elsewhere.
However, the unaccounted pins are likely an ephemeral state.

In this situation, MADV_COLLAPSE returns -EINVAL when it should return
-EAGAIN.  This could cause userspace to conclude that the syscall
failed, when it in fact could succeed by retrying.

Link: https://lkml.kernel.org/r/20230125015738.912924-1-zokeefe@google.com
Fixes: 7d8faaf155 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse")
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reported-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:59:49 +01:00
Qi Zheng
86e3baf6a6 mm: shrinkers: fix deadlock in shrinker debugfs
commit badc28d4924bfed73efc93f716a0c3aa3afbdf6f upstream.

The debugfs_remove_recursive() is invoked by unregister_shrinker(), which
is holding the write lock of shrinker_rwsem.  It will waits for the
handler of debugfs file complete.  The handler also needs to hold the read
lock of shrinker_rwsem to do something.  So it may cause the following
deadlock:

 	CPU0				CPU1

debugfs_file_get()
shrinker_debugfs_count_show()/shrinker_debugfs_scan_write()

     				unregister_shrinker()
				--> down_write(&shrinker_rwsem);
				    debugfs_remove_recursive()
					// wait for (A)
				    --> wait_for_completion();

    // wait for (B)
--> down_read_killable(&shrinker_rwsem)
debugfs_file_put() -- (A)

				    up_write() -- (B)

The down_read_killable() can be killed, so that the above deadlock can be
recovered.  But it still requires an extra kill action, otherwise it will
block all subsequent shrinker-related operations, so it's better to fix
it.

[akpm@linux-foundation.org: fix CONFIG_SHRINKER_DEBUG=n stub]
Link: https://lkml.kernel.org/r/20230202105612.64641-1-zhengqi.arch@bytedance.com
Fixes: 5035ebc644 ("mm: shrinkers: introduce debugfs interface for memory shrinkers")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:59:46 +01:00
Christophe Leroy
b184caaf62 kasan: fix Oops due to missing calls to kasan_arch_is_ready()
commit 55d77bae73426237b3c74c1757a894b056550dff upstream.

On powerpc64, you can build a kernel with KASAN as soon as you build it
with RADIX MMU support.  However if the CPU doesn't have RADIX MMU, KASAN
isn't enabled at init and the following Oops is encountered.

  [    0.000000][    T0] KASAN not enabled as it requires radix!

  [    4.484295][   T26] BUG: Unable to handle kernel data access at 0xc00e000000804a04
  [    4.485270][   T26] Faulting instruction address: 0xc00000000062ec6c
  [    4.485748][   T26] Oops: Kernel access of bad area, sig: 11 [#1]
  [    4.485920][   T26] BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  [    4.486259][   T26] Modules linked in:
  [    4.486637][   T26] CPU: 0 PID: 26 Comm: kworker/u2:2 Not tainted 6.2.0-rc3-02590-gf8a023b0a805 #249
  [    4.486907][   T26] Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1200 0xf000005 of:SLOF,HEAD pSeries
  [    4.487445][   T26] Workqueue: eval_map_wq .tracer_init_tracefs_work_func
  [    4.488744][   T26] NIP:  c00000000062ec6c LR: c00000000062bb84 CTR: c0000000002ebcd0
  [    4.488867][   T26] REGS: c0000000049175c0 TRAP: 0380   Not tainted  (6.2.0-rc3-02590-gf8a023b0a805)
  [    4.489028][   T26] MSR:  8000000002009032 <SF,VEC,EE,ME,IR,DR,RI>  CR: 44002808  XER: 00000000
  [    4.489584][   T26] CFAR: c00000000062bb80 IRQMASK: 0
  [    4.489584][   T26] GPR00: c0000000005624d4 c000000004917860 c000000001cfc000 1800000000804a04
  [    4.489584][   T26] GPR04: c0000000003a2650 0000000000000cc0 c00000000000d3d8 c00000000000d3d8
  [    4.489584][   T26] GPR08: c0000000049175b0 a80e000000000000 0000000000000000 0000000017d78400
  [    4.489584][   T26] GPR12: 0000000044002204 c000000003790000 c00000000435003c c0000000043f1c40
  [    4.489584][   T26] GPR16: c0000000043f1c68 c0000000043501a0 c000000002106138 c0000000043f1c08
  [    4.489584][   T26] GPR20: c0000000043f1c10 c0000000043f1c20 c000000004146c40 c000000002fdb7f8
  [    4.489584][   T26] GPR24: c000000002fdb834 c000000003685e00 c000000004025030 c000000003522e90
  [    4.489584][   T26] GPR28: 0000000000000cc0 c0000000003a2650 c000000004025020 c000000004025020
  [    4.491201][   T26] NIP [c00000000062ec6c] .kasan_byte_accessible+0xc/0x20
  [    4.491430][   T26] LR [c00000000062bb84] .__kasan_check_byte+0x24/0x90
  [    4.491767][   T26] Call Trace:
  [    4.491941][   T26] [c000000004917860] [c00000000062ae70] .__kasan_kmalloc+0xc0/0x110 (unreliable)
  [    4.492270][   T26] [c0000000049178f0] [c0000000005624d4] .krealloc+0x54/0x1c0
  [    4.492453][   T26] [c000000004917990] [c0000000003a2650] .create_trace_option_files+0x280/0x530
  [    4.492613][   T26] [c000000004917a90] [c000000002050d90] .tracer_init_tracefs_work_func+0x274/0x2c0
  [    4.492771][   T26] [c000000004917b40] [c0000000001f9948] .process_one_work+0x578/0x9f0
  [    4.492927][   T26] [c000000004917c30] [c0000000001f9ebc] .worker_thread+0xfc/0x950
  [    4.493084][   T26] [c000000004917d60] [c00000000020be84] .kthread+0x1a4/0x1b0
  [    4.493232][   T26] [c000000004917e10] [c00000000000d3d8] .ret_from_kernel_thread+0x58/0x60
  [    4.495642][   T26] Code: 60000000 7cc802a6 38a00000 4bfffc78 60000000 7cc802a6 38a00001 4bfffc68 60000000 3d20a80e 7863e8c2 792907c6 <7c6348ae> 20630007 78630fe0 68630001
  [    4.496704][   T26] ---[ end trace 0000000000000000 ]---

The Oops is due to kasan_byte_accessible() not checking the readiness of
KASAN.  Add missing call to kasan_arch_is_ready() and bail out when not
ready.  The same problem is observed with ____kasan_kfree_large() so fix
it the same.

Also, as KASAN is not available and no shadow area is allocated for linear
memory mapping, there is no point in allocating shadow mem for vmalloc
memory as shown below in /sys/kernel/debug/kernel_page_tables

  ---[ kasan shadow mem start ]---
  0xc00f000000000000-0xc00f00000006ffff  0x00000000040f0000       448K         r  w       pte  valid  present        dirty  accessed
  0xc00f000000860000-0xc00f00000086ffff  0x000000000ac10000        64K         r  w       pte  valid  present        dirty  accessed
  0xc00f3ffffffe0000-0xc00f3fffffffffff  0x0000000004d10000       128K         r  w       pte  valid  present        dirty  accessed
  ---[ kasan shadow mem end ]---

So, also verify KASAN readiness before allocating and poisoning
shadow mem for VMAs.

Link: https://lkml.kernel.org/r/150768c55722311699fdcf8f5379e8256749f47d.1674716617.git.christophe.leroy@csgroup.eu
Fixes: 41b7a347bf ("powerpc: Book3S 64-bit outline-only KASAN support")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reported-by: Nathan Lynch <nathanl@linux.ibm.com>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>	[5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:59:46 +01:00
David Chen
3b4c045a98 Fix page corruption caused by racy check in __free_pages
commit 462a8e08e0e6287e5ce13187257edbf24213ed03 upstream.

When we upgraded our kernel, we started seeing some page corruption like
the following consistently:

  BUG: Bad page state in process ganesha.nfsd  pfn:1304ca
  page:0000000022261c55 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x1304ca
  flags: 0x17ffffc0000000()
  raw: 0017ffffc0000000 ffff8a513ffd4c98 ffffeee24b35ec08 0000000000000000
  raw: 0000000000000000 0000000000000001 00000000ffffff7f 0000000000000000
  page dumped because: nonzero mapcount
  CPU: 0 PID: 15567 Comm: ganesha.nfsd Kdump: loaded Tainted: P    B      O      5.10.158-1.nutanix.20221209.el7.x86_64 #1
  Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016
  Call Trace:
   dump_stack+0x74/0x96
   bad_page.cold+0x63/0x94
   check_new_page_bad+0x6d/0x80
   rmqueue+0x46e/0x970
   get_page_from_freelist+0xcb/0x3f0
   ? _cond_resched+0x19/0x40
   __alloc_pages_nodemask+0x164/0x300
   alloc_pages_current+0x87/0xf0
   skb_page_frag_refill+0x84/0x110
   ...

Sometimes, it would also show up as corruption in the free list pointer
and cause crashes.

After bisecting the issue, we found the issue started from commit
e320d3012d ("mm/page_alloc.c: fix freeing non-compound pages"):

	if (put_page_testzero(page))
		free_the_page(page, order);
	else if (!PageHead(page))
		while (order-- > 0)
			free_the_page(page + (1 << order), order);

So the problem is the check PageHead is racy because at this point we
already dropped our reference to the page.  So even if we came in with
compound page, the page can already be freed and PageHead can return
false and we will end up freeing all the tail pages causing double free.

Fixes: e320d3012d ("mm/page_alloc.c: fix freeing non-compound pages")
Link: https://lore.kernel.org/lkml/BYAPR02MB448855960A9656EEA81141FC94D99@BYAPR02MB4488.namprd02.prod.outlook.com/
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-14 19:11:54 +01:00
Mike Kravetz
d8b46cc1cf migrate: hugetlb: check for hugetlb shared PMD in node migration
commit 73bdf65ea74857d7fb2ec3067a3cec0e261b1462 upstream.

migrate_pages/mempolicy semantics state that CAP_SYS_NICE is required to
move pages shared with another process to a different node.  page_mapcount
> 1 is being used to determine if a hugetlb page is shared.  However, a
hugetlb page will have a mapcount of 1 if mapped by multiple processes via
a shared PMD.  As a result, hugetlb pages shared by multiple processes and
mapped with a shared PMD can be moved by a process without CAP_SYS_NICE.

To fix, check for a shared PMD if mapcount is 1.  If a shared PMD is found
consider the page shared.

Link: https://lkml.kernel.org/r/20230126222721.222195-3-mike.kravetz@oracle.com
Fixes: e2d8cf4055 ("migrate: add hugepage migration code to migrate_pages()")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:23 +01:00
Zach O'Keefe
96aaaf8666 mm/MADV_COLLAPSE: catch !none !huge !bad pmd lookups
commit edb5d0cf5525357652aff6eacd9850b8ced07143 upstream.

In commit 34488399fa ("mm/madvise: add file and shmem support to
MADV_COLLAPSE") we make the following change to find_pmd_or_thp_or_none():

	-       if (!pmd_present(pmde))
	-               return SCAN_PMD_NULL;
	+       if (pmd_none(pmde))
	+               return SCAN_PMD_NONE;

This was for-use by MADV_COLLAPSE file/shmem codepaths, where
MADV_COLLAPSE might identify a pte-mapped hugepage, only to have
khugepaged race-in, free the pte table, and clear the pmd.  Such codepaths
include:

A) If we find a suitably-aligned compound page of order HPAGE_PMD_ORDER
   already in the pagecache.
B) In retract_page_tables(), if we fail to grab mmap_lock for the target
   mm/address.

In these cases, collapse_pte_mapped_thp() really does expect a none (not
just !present) pmd, and we want to suitably identify that case separate
from the case where no pmd is found, or it's a bad-pmd (of course, many
things could happen once we drop mmap_lock, and the pmd could plausibly
undergo multiple transitions due to intervening fault, split, etc).
Regardless, the code is prepared install a huge-pmd only when the existing
pmd entry is either a genuine pte-table-mapping-pmd, or the none-pmd.

However, the commit introduces a logical hole; namely, that we've allowed
!none- && !huge- && !bad-pmds to be classified as genuine
pte-table-mapping-pmds.  One such example that could leak through are swap
entries.  The pmd values aren't checked again before use in
pte_offset_map_lock(), which is expecting nothing less than a genuine
pte-table-mapping-pmd.

We want to put back the !pmd_present() check (below the pmd_none() check),
but need to be careful to deal with subtleties in pmd transitions and
treatments by various arch.

The issue is that __split_huge_pmd_locked() temporarily clears the present
bit (or otherwise marks the entry as invalid), but pmd_present() and
pmd_trans_huge() still need to return true while the pmd is in this
transitory state.  For example, x86's pmd_present() also checks the
_PAGE_PSE , riscv's version also checks the _PAGE_LEAF bit, and arm64 also
checks a PMD_PRESENT_INVALID bit.

Covering all 4 cases for x86 (all checks done on the same pmd value):

1) pmd_present() && pmd_trans_huge()
   All we actually know here is that the PSE bit is set. Either:
   a) We aren't racing with __split_huge_page(), and PRESENT or PROTNONE
      is set.
      => huge-pmd
   b) We are currently racing with __split_huge_page().  The danger here
      is that we proceed as-if we have a huge-pmd, but really we are
      looking at a pte-mapping-pmd.  So, what is the risk of this
      danger?

      The only relevant path is:

	madvise_collapse() -> collapse_pte_mapped_thp()

      Where we might just incorrectly report back "success", when really
      the memory isn't pmd-backed.  This is fine, since split could
      happen immediately after (actually) successful madvise_collapse().
      So, it should be safe to just assume huge-pmd here.

2) pmd_present() && !pmd_trans_huge()
   Either:
   a) PSE not set and either PRESENT or PROTNONE is.
      => pte-table-mapping pmd (or PROT_NONE)
   b) devmap.  This routine can be called immediately after
      unlocking/locking mmap_lock -- or called with no locks held (see
      khugepaged_scan_mm_slot()), so previous VMA checks have since been
      invalidated.

3) !pmd_present() && pmd_trans_huge()
  Not possible.

4) !pmd_present() && !pmd_trans_huge()
  Neither PRESENT nor PROTNONE set
  => not present

I've checked all archs that implement pmd_trans_huge() (arm64, riscv,
powerpc, longarch, x86, mips, s390) and this logic roughly translates
(though devmap treatment is unique to x86 and powerpc, and (3) doesn't
necessarily hold in general -- but that doesn't matter since
!pmd_present() always takes failure path).

Also, add a comment above find_pmd_or_thp_or_none() to help future
travelers reason about the validity of the code; namely, the possible
mutations that might happen out from under us, depending on how mmap_lock
is held (if at all).

Link: https://lkml.kernel.org/r/20230125225358.2576151-1-zokeefe@google.com
Fixes: 34488399fa ("mm/madvise: add file and shmem support to MADV_COLLAPSE")
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reported-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:22 +01:00
Vlastimil Babka
97f17a7372 mm, mremap: fix mremap() expanding for vma's with vm_ops->close()
commit d014cd7c1c358edc3ea82ebf327a036a42ed0164 upstream.

Fabian has reported another regression in 6.1 due to ca3d76b0aa ("mm:
add merging after mremap resize").  The problem is that vma_merge() can
fail when vma has a vm_ops->close() method, causing is_mergeable_vma()
test to be negative.  This was happening for vma mapping a file from
fuse-overlayfs, which does have the method.  But when we are simply
expanding the vma, we never remove it due to the "merge" with the added
area, so the test should not prevent the expansion.

As a quick fix, check for such vmas and expand them using vma_adjust()
directly as was done before commit ca3d76b0aa.  For a more robust long
term solution we should try to limit the check for vma_ops->close only to
cases that actually result in vma removal, so that no merge would be
prevented unnecessarily.

[akpm@linux-foundation.org: fix indenting whitespace, reflow comment]
Link: https://lkml.kernel.org/r/20230117101939.9753-1-vbabka@suse.cz
Fixes: ca3d76b0aa ("mm: add merging after mremap resize")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Fabian Vogt <fvogt@suse.com>
  Link: https://bugzilla.suse.com/show_bug.cgi?id=1206359#c35
Tested-by: Fabian Vogt <fvogt@suse.com>
Cc: Jakub Matěna <matenajakub@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:22 +01:00
Jann Horn
acb08187b5 mm/khugepaged: fix ->anon_vma race
commit 023f47a8250c6bdb4aebe744db4bf7f73414028b upstream.

If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires
it to be locked.

Page table traversal is allowed under any one of the mmap lock, the
anon_vma lock (if the VMA is associated with an anon_vma), and the
mapping lock (if the VMA is associated with a mapping); and so to be
able to remove page tables, we must hold all three of them.
retract_page_tables() bails out if an ->anon_vma is attached, but does
this check before holding the mmap lock (as the comment above the check
explains).

If we racily merged an existing ->anon_vma (shared with a child
process) from a neighboring VMA, subsequent rmap traversals on pages
belonging to the child will be able to see the page tables that we are
concurrently removing while assuming that nothing else can access them.

Repeat the ->anon_vma check once we hold the mmap lock to ensure that
there really is no concurrent page table access.

Hitting this bug causes a lockdep warning in collapse_and_free_pmd(),
in the line "lockdep_assert_held_write(&vma->anon_vma->root->rwsem)".
It can also lead to use-after-free access.

Link: https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_POneSDF+A@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230111133351.807024-1-jannh@google.com
Fixes: f3f0e1d215 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Jann Horn <jannh@google.com>
Reported-by: Zach O'Keefe <zokeefe@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@intel.linux.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:22 +01:00
Longlong Xia
49178d4d61 mm/swapfile: add cond_resched() in get_swap_pages()
commit 7717fc1a12f88701573f9ed897cc4f6699c661e3 upstream.

The softlockup still occurs in get_swap_pages() under memory pressure.  64
CPU cores, 64GB memory, and 28 zram devices, the disksize of each zram
device is 50MB with same priority as si.  Use the stress-ng tool to
increase memory pressure, causing the system to oom frequently.

The plist_for_each_entry_safe() loops in get_swap_pages() could reach tens
of thousands of times to find available space (extreme case:
cond_resched() is not called in scan_swap_map_slots()).  Let's add
cond_resched() into get_swap_pages() when failed to find available space
to avoid softlockup.

Link: https://lkml.kernel.org/r/20230128094757.1060525-1-xialonglong1@huawei.com
Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:22 +01:00
Peter Xu
2d11727655 mm/uffd: fix pte marker when fork() without fork event
commit 49d6d7fb631345b0f2957a7c4be24ad63903150f upstream.

Patch series "mm: Fixes on pte markers".

Patch 1 resolves the syzkiller report from Pengfei.

Patch 2 further harden pte markers when used with the recent swapin error
markers.  The major case is we should persist a swapin error marker after
fork(), so child shouldn't read a corrupted page.


This patch (of 2):

When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may
have it and has pte marker installed.  The warning is improper along with
the comment.  The right thing is to inherit the pte marker when needed, or
keep the dst pte empty.

A vague guess is this happened by an accident when there's the prior patch
to introduce src/dst vma into this helper during the uffd-wp feature got
developed and I probably messed up in the rebase, since if we replace
dst_vma with src_vma the warning & comment it all makes sense too.

Hugetlb did exactly the right here (copy_hugetlb_page_range()).  Fix the
general path.

Reproducer:

https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c

Bugzilla report: https://bugzilla.kernel.org/show_bug.cgi?id=216808

Link: https://lkml.kernel.org/r/20221214200453.1772655-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20221214200453.1772655-2-peterx@redhat.com
Fixes: c56d1b62cc ("mm/shmem: handle uffd-wp during fork()")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: <stable@vger.kernel.org> # 5.19+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:22 +01:00
Yu Zhao
0444802231 mm: multi-gen LRU: fix crash during cgroup migration
commit de08eaa6156405f2e9369f06ba5afae0e4ab3b62 upstream.

lru_gen_migrate_mm() assumes lru_gen_add_mm() runs prior to itself.  This
isn't true for the following scenario:

    CPU 1                         CPU 2

  clone()
    cgroup_can_fork()
                                cgroup_procs_write()
    cgroup_post_fork()
                                  task_lock()
                                  lru_gen_migrate_mm()
                                  task_unlock()
    task_lock()
    lru_gen_add_mm()
    task_unlock()

And when the above happens, kernel crashes because of linked list
corruption (mm_struct->lru_gen.list).

Link: https://lore.kernel.org/r/20230115134651.30028-1-msizanoen@qtmlabs.xyz/
Link: https://lkml.kernel.org/r/20230116034405.2960276-1-yuzhao@google.com
Fixes: bd74fdaea1 ("mm: multi-gen LRU: support page table walks")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: msizanoen <msizanoen@qtmlabs.xyz>
Tested-by: msizanoen <msizanoen@qtmlabs.xyz>
Cc: <stable@vger.kernel.org>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:20 +01:00
Al Viro
5a19095103 use less confusing names for iov_iter direction initializers
[ Upstream commit de4eda9de2d957ef2d6a8365a01e26a435e958cb ]

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: 6dd88fd59da8 ("vhost-scsi: unbreak any layout for response")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-09 11:28:04 +01:00
Vlastimil Babka
e1275a6b2d Revert "mm/compaction: fix set skip in fast_find_migrateblock"
commit 95e7a450b8190673675836bfef236262ceff084a upstream.

This reverts commit 7efc3b7261.

We have got openSUSE reports (Link 1) for 6.1 kernel with khugepaged
stalling CPU for long periods of time.  Investigation of tracepoint data
shows that compaction is stuck in repeating fast_find_migrateblock()
based migrate page isolation, and then fails to migrate all isolated
pages.

Commit 7efc3b7261 ("mm/compaction: fix set skip in fast_find_migrateblock")
was suspected as it was merged in 6.1 and in theory can indeed remove a
termination condition for fast_find_migrateblock() under certain
conditions, as it removes a place that always marks a scanned pageblock
from being re-scanned.  There are other such places, but those can be
skipped under certain conditions, which seems to match the tracepoint
data.

Testing of revert also appears to have resolved the issue, thus revert
the commit until a more robust solution for the original problem is
developed.

It's also likely this will fix qemu stalls with 6.1 kernel reported in
Link 2, but that is not yet confirmed.

Link: https://bugzilla.suse.com/show_bug.cgi?id=1206848
Link: https://lore.kernel.org/kvm/b8017e09-f336-3035-8344-c549086c2340@kernel.org/
Link: https://lore.kernel.org/lkml/20230125134434.18017-1-mgorman@techsingularity.net/
Fixes: 7efc3b7261 ("mm/compaction: fix set skip in fast_find_migrateblock")
Cc: <stable@vger.kernel.org>
Tested-by: Pedro Falcato <pedro.falcato@gmail.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-01 08:34:49 +01:00
Kees Cook
13aa82f007 panic: Consolidate open-coded panic_on_warn checks
commit 79cc1ba7badf9e7a12af99695a557e9ce27ee967 upstream.

Several run-time checkers (KASAN, UBSAN, KFENCE, KCSAN, sched) roll
their own warnings, and each check "panic_on_warn". Consolidate this
into a single function so that future instrumentation can be added in
a single location.

Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Gow <davidgow@google.com>
Cc: tangmeng <tangmeng@uniontech.com>
Cc: Jann Horn <jannh@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: kasan-dev@googlegroups.com
Cc: linux-mm@kvack.org
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20221117234328.594699-4-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:41 +01:00
Zach O'Keefe
f2f52dd4f5 mm/MADV_COLLAPSE: don't expand collapse when vm_end is past requested end
commit 52dc031088f00e323140ece4004e70c33153c6dd upstream.

MADV_COLLAPSE acts on one hugepage-aligned/sized region at a time, until
it has collapsed all eligible memory contained within the bounds supplied
by the user.

At the top of each hugepage iteration we (re)lock mmap_lock and
(re)validate the VMA for eligibility and update variables that might have
changed while mmap_lock was dropped.  One thing that might occur is that
the VMA could be resized, and as such, we refetch vma->vm_end to make sure
we don't collapse past the end of the VMA's new end.

However, it's possible that when refetching vma->vm_end that we expand the
region acted on by MADV_COLLAPSE if vma->vm_end is greater than size+len
supplied by the user.

The consequence here is that we may attempt to collapse more memory than
requested, possibly yielding either "too much success" or "false failure"
user-visible results.  An example of the former is if we MADV_COLLAPSE the
first 4MiB of a 2TiB mmap()'d file, the incorrect refetch would cause the
operation to block for much longer than anticipated as we attempt to
collapse the entire TiB region.  An example of the latter is that applying
MADV_COLLPSE to a 4MiB file mapped to the start of a 6MiB VMA will
successfully collapse the first 4MiB, then incorrectly attempt to collapse
the last hugepage-aligned/sized region -- fail (since readahead/page cache
lookup will fail) -- and report a failure to the user.

I don't believe there is a kernel stability concern here as we always
(re)validate the VMA / region accordingly.  Also as Hugh mentions, the
user-visible effects are: we try to collapse more memory than requested
by the user, and/or failing an operation that should have otherwise
succeeded.  An example is trying to collapse a 4MiB file contained
within a 12MiB VMA.

Don't expand the acted-on region when refetching vma->vm_end.

Link: https://lkml.kernel.org/r/20221224082035.3197140-1-zokeefe@google.com
Fixes: 4d24de9425 ("mm: MADV_COLLAPSE: refetch vm_end after reacquiring mmap_lock")
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reported-by: Hugh Dickins <hughd@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
David Hildenbrand
bcde505af1 mm/userfaultfd: enable writenotify while userfaultfd-wp is enabled for a VMA
commit 51d3d5eb74ff53b92dcff48b30ae2ed8edd85a32 upstream.

Currently, we don't enable writenotify when enabling userfaultfd-wp on a
shared writable mapping (for now only shmem and hugetlb).  The consequence
is that vma->vm_page_prot will still include write permissions, to be set
as default for all PTEs that get remapped (e.g., mprotect(), NUMA hinting,
page migration, ...).

So far, vma->vm_page_prot is assumed to be a safe default, meaning that we
only add permissions (e.g., mkwrite) but not remove permissions (e.g.,
wrprotect).  For example, when enabling softdirty tracking, we enable
writenotify.  With uffd-wp on shared mappings, that changed.  More details
on vma->vm_page_prot semantics were summarized in [1].

This is problematic for uffd-wp: we'd have to manually check for a uffd-wp
PTEs/PMDs and manually write-protect PTEs/PMDs, which is error prone.
Prone to such issues is any code that uses vma->vm_page_prot to set PTE
permissions: primarily pte_modify() and mk_pte().

Instead, let's enable writenotify such that PTEs/PMDs/...  will be mapped
write-protected as default and we will only allow selected PTEs that are
definitely safe to be mapped without write-protection (see
can_change_pte_writable()) to be writable.  In the future, we might want
to enable write-bit recovery -- e.g., can_change_pte_writable() -- at more
locations, for example, also when removing uffd-wp protection.

This fixes two known cases:

(a) remove_migration_pte() mapping uffd-wp'ed PTEs writable, resulting
    in uffd-wp not triggering on write access.
(b) do_numa_page() / do_huge_pmd_numa_page() mapping uffd-wp'ed PTEs/PMDs
    writable, resulting in uffd-wp not triggering on write access.

Note that do_numa_page() / do_huge_pmd_numa_page() can be reached even
without NUMA hinting (which currently doesn't seem to be applicable to
shmem), for example, by using uffd-wp with a PROT_WRITE shmem VMA.  On
such a VMA, userfaultfd-wp is currently non-functional.

Note that when enabling userfaultfd-wp, there is no need to walk page
tables to enforce the new default protection for the PTEs: we know that
they cannot be uffd-wp'ed yet, because that can only happen after enabling
uffd-wp for the VMA in general.

Also note that this makes mprotect() on ranges with uffd-wp'ed PTEs not
accidentally set the write bit -- which would result in uffd-wp not
triggering on later write access.  This commit makes uffd-wp on shmem
behave just like uffd-wp on anonymous memory in that regard, even though,
mixing mprotect with uffd-wp is controversial.

[1] https://lkml.kernel.org/r/92173bad-caa3-6b43-9d1e-9a471fdbc184@redhat.com

Link: https://lkml.kernel.org/r/20221209080912.7968-1-david@redhat.com
Fixes: b1f9e87686 ("mm/uffd: enable write protection for shmem & hugetlbfs")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Ives van Hoorne <ives@codesandbox.io>
Debugged-by: Peter Xu <peterx@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Peter Xu
3b8ede6665 mm/hugetlb: pre-allocate pgtable pages for uffd wr-protects
commit fed15f1345dc8a7fc8baa81e8b55c3ba010d7f4b upstream.

Userfaultfd-wp uses pte markers to mark wr-protected pages for both shmem
and hugetlb.  Shmem has pre-allocation ready for markers, but hugetlb path
was overlooked.

Doing so by calling huge_pte_alloc() if the initial pgtable walk fails to
find the huge ptep.  It's possible that huge_pte_alloc() can fail with
high memory pressure, in that case stop the loop immediately and fail
silently.  This is not the most ideal solution but it matches with what we
do with shmem meanwhile it avoids the splat in dmesg.

Link: https://lkml.kernel.org/r/20230104225207.1066932-2-peterx@redhat.com
Fixes: 60dfaad65a ("mm/hugetlb: allow uffd wr-protect none ptes")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: James Houghton <jthoughton@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: James Houghton <jthoughton@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: <stable@vger.kernel.org>	[5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
David Hildenbrand
8d6a675cd7 mm/hugetlb: fix uffd-wp handling for migration entries in hugetlb_change_protection()
commit 44f86392bdd165da7e43d3c772aeb1e128ffd6c8 upstream.

We have to update the uffd-wp SWP PTE bit independent of the type of
migration entry.  Currently, if we're unlucky and we want to install/clear
the uffd-wp bit just while we're migrating a read-only mapped hugetlb
page, we would miss to set/clear the uffd-wp bit.

Further, if we're processing a readable-exclusive migration entry and
neither want to set or clear the uffd-wp bit, we could currently end up
losing the uffd-wp bit.  Note that the same would hold for writable
migrating entries, however, having a writable migration entry with the
uffd-wp bit set would already mean that something went wrong.

Note that the change from !is_readable_migration_entry ->
writable_migration_entry is harmless and actually cleaner, as raised by
Miaohe Lin and discussed in [1].

[1] https://lkml.kernel.org/r/90dd6a93-4500-e0de-2bf0-bf522c311b0c@huawei.com

Link: https://lkml.kernel.org/r/20221222205511.675832-3-david@redhat.com
Fixes: 60dfaad65a ("mm/hugetlb: allow uffd wr-protect none ptes")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:35 +01:00
David Hildenbrand
6062c992e9 mm/hugetlb: fix PTE marker handling in hugetlb_change_protection()
commit 0e678153f5be7e6c8d28835f5a678618da4b7a9c upstream.

Patch series "mm/hugetlb: uffd-wp fixes for hugetlb_change_protection()".

Playing with virtio-mem and background snapshots (using uffd-wp) on
hugetlb in QEMU, I managed to trigger a VM_BUG_ON().  Looking into the
details, hugetlb_change_protection() seems to not handle uffd-wp correctly
in all cases.

Patch #1 fixes my test case.  I don't have reproducers for patch #2, as it
requires running into migration entries.

I did not yet check in detail yet if !hugetlb code requires similar care.


This patch (of 2):

There are two problematic cases when stumbling over a PTE marker in
hugetlb_change_protection():

(1) We protect an uffd-wp PTE marker a second time using uffd-wp: we will
    end up in the "!huge_pte_none(pte)" case and mess up the PTE marker.

(2) We unprotect a uffd-wp PTE marker: we will similarly end up in the
    "!huge_pte_none(pte)" case even though we cleared the PTE, because
    the "pte" variable is stale. We'll mess up the PTE marker.

For example, if we later stumble over such a "wrongly modified" PTE marker,
we'll treat it like a present PTE that maps some garbage page.

This can, for example, be triggered by mapping a memfd backed by huge
pages, registering uffd-wp, uffd-wp'ing an unmapped page and (a)
uffd-wp'ing it a second time; or (b) uffd-unprotecting it; or (c)
unregistering uffd-wp. Then, ff we trigger fallocate(FALLOC_FL_PUNCH_HOLE)
on that file range, we will run into a VM_BUG_ON:

[  195.039560] page:00000000ba1f2987 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x0
[  195.039565] flags: 0x7ffffc0001000(reserved|node=0|zone=0|lastcpupid=0x1fffff)
[  195.039568] raw: 0007ffffc0001000 ffffe742c0000008 ffffe742c0000008 0000000000000000
[  195.039569] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
[  195.039569] page dumped because: VM_BUG_ON_PAGE(compound && !PageHead(page))
[  195.039573] ------------[ cut here ]------------
[  195.039574] kernel BUG at mm/rmap.c:1346!
[  195.039579] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[  195.039581] CPU: 7 PID: 4777 Comm: qemu-system-x86 Not tainted 6.0.12-200.fc36.x86_64 #1
[  195.039583] Hardware name: LENOVO 20WNS1F81N/20WNS1F81N, BIOS N35ET50W (1.50 ) 09/15/2022
[  195.039584] RIP: 0010:page_remove_rmap+0x45b/0x550
[  195.039588] Code: [...]
[  195.039589] RSP: 0018:ffffbc03c3633ba8 EFLAGS: 00010292
[  195.039591] RAX: 0000000000000040 RBX: ffffe742c0000000 RCX: 0000000000000000
[  195.039592] RDX: 0000000000000002 RSI: ffffffff8e7aac1a RDI: 00000000ffffffff
[  195.039592] RBP: 0000000000000001 R08: 0000000000000000 R09: ffffbc03c3633a08
[  195.039593] R10: 0000000000000003 R11: ffffffff8f146328 R12: ffff9b04c42754b0
[  195.039594] R13: ffffffff8fcc6328 R14: ffffbc03c3633c80 R15: ffff9b0484ab9100
[  195.039595] FS:  00007fc7aaf68640(0000) GS:ffff9b0bbf7c0000(0000) knlGS:0000000000000000
[  195.039596] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  195.039597] CR2: 000055d402c49110 CR3: 0000000159392003 CR4: 0000000000772ee0
[  195.039598] PKRU: 55555554
[  195.039599] Call Trace:
[  195.039600]  <TASK>
[  195.039602]  __unmap_hugepage_range+0x33b/0x7d0
[  195.039605]  unmap_hugepage_range+0x55/0x70
[  195.039608]  hugetlb_vmdelete_list+0x77/0xa0
[  195.039611]  hugetlbfs_fallocate+0x410/0x550
[  195.039612]  ? _raw_spin_unlock_irqrestore+0x23/0x40
[  195.039616]  vfs_fallocate+0x12e/0x360
[  195.039618]  __x64_sys_fallocate+0x40/0x70
[  195.039620]  do_syscall_64+0x58/0x80
[  195.039623]  ? syscall_exit_to_user_mode+0x17/0x40
[  195.039624]  ? do_syscall_64+0x67/0x80
[  195.039626]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[  195.039628] RIP: 0033:0x7fc7b590651f
[  195.039653] Code: [...]
[  195.039654] RSP: 002b:00007fc7aaf66e70 EFLAGS: 00000293 ORIG_RAX: 000000000000011d
[  195.039655] RAX: ffffffffffffffda RBX: 0000558ef4b7f370 RCX: 00007fc7b590651f
[  195.039656] RDX: 0000000018000000 RSI: 0000000000000003 RDI: 000000000000000c
[  195.039657] RBP: 0000000008000000 R08: 0000000000000000 R09: 0000000000000073
[  195.039658] R10: 0000000008000000 R11: 0000000000000293 R12: 0000000018000000
[  195.039658] R13: 00007fb8bbe00000 R14: 000000000000000c R15: 0000000000001000
[  195.039661]  </TASK>

Fix it by not going into the "!huge_pte_none(pte)" case if we stumble over
an exclusive marker.  spin_unlock() + continue would get the job done.

However, instead, make it clearer that there are no fall-through
statements: we process each case (hwpoison, migration, marker, !none,
none) and then unlock the page table to continue with the next PTE.  Let's
avoid "continue" statements and use a single spin_unlock() at the end.

Link: https://lkml.kernel.org/r/20221222205511.675832-1-david@redhat.com
Link: https://lkml.kernel.org/r/20221222205511.675832-2-david@redhat.com
Fixes: 60dfaad65a ("mm/hugetlb: allow uffd wr-protect none ptes")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:35 +01:00
Hugh Dickins
48b94e4998 mm/khugepaged: fix collapse_pte_mapped_thp() to allow anon_vma
commit ab0c3f1251b4670978fde0bd54161795a139b060 upstream.

uprobe_write_opcode() uses collapse_pte_mapped_thp() to restore huge pmd,
when removing a breakpoint from hugepage text: vma->anon_vma is always set
in that case, so undo the prohibition.  And MADV_COLLAPSE ought to be able
to collapse some page tables in a vma which happens to have anon_vma set
from CoWing elsewhere.

Is anon_vma lock required?  Almost not: if any page other than expected
subpage of the non-anon huge page is found in the page table, collapse is
aborted without making any change.  However, it is possible that an anon
page was CoWed from this extent in another mm or vma, in which case a
concurrent lookup might look here: so keep it away while clearing pmd (but
perhaps we shall go back to using pmd_lock() there in future).

Note that collapse_pte_mapped_thp() is exceptional in freeing a page table
without having cleared its ptes: I'm uneasy about that, and had thought
pte_clear()ing appropriate; but exclusive i_mmap lock does fix the
problem, and we would have to move the mmu_notification if clearing those
ptes.

What this fixes is not a dangerous instability.  But I suggest Cc stable
because uprobes "healing" has regressed in that way, so this should follow
8d3c106e19 into those stable releases where it was backported (and may
want adjustment there - I'll supply backports as needed).

Link: https://lkml.kernel.org/r/b740c9fb-edba-92ba-59fb-7a5592e5dfc@google.com
Fixes: 8d3c106e19 ("mm/khugepaged: take the right locks for page table retraction")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org>    [5.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:33 +01:00
James Houghton
63f71b8609 hugetlb: unshare some PMDs when splitting VMAs
commit b30c14cd61025eeea2f2e8569606cd167ba9ad2d upstream.

PMD sharing can only be done in PUD_SIZE-aligned pieces of VMAs; however,
it is possible that HugeTLB VMAs are split without unsharing the PMDs
first.

Without this fix, it is possible to hit the uffd-wp-related WARN_ON_ONCE
in hugetlb_change_protection [1].  The key there is that
hugetlb_unshare_all_pmds will not attempt to unshare PMDs in
non-PUD_SIZE-aligned sections of the VMA.

It might seem ideal to unshare in hugetlb_vm_op_open, but we need to
unshare in both the new and old VMAs, so unsharing in hugetlb_vm_op_split
seems natural.

[1]: https://lore.kernel.org/linux-mm/CADrL8HVeOkj0QH5VZZbRzybNE8CG-tEGFshnA+bG9nMgcWtBSg@mail.gmail.com/

Link: https://lkml.kernel.org/r/20230104231910.1464197-1-jthoughton@google.com
Fixes: 6dfeaff93b ("hugetlb/userfaultfd: unshare all pmds for hugetlbfs when register wp")
Signed-off-by: James Houghton <jthoughton@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:33 +01:00
Zach O'Keefe
1cb76f5669 mm/shmem: restore SHMEM_HUGE_DENY precedence over MADV_COLLAPSE
commit 3de0c269adc6c2fac0bb1fb11965f0de699dc32b upstream.

SHMEM_HUGE_DENY is for emergency use by the admin, to disable allocation
of shmem huge pages if, for example, a dangerous bug is found in their
usage: see "deny" in Documentation/mm/transhuge.rst.  An app using
madvise(,,MADV_COLLAPSE) should not be allowed to override it: restore its
precedence over shmem_huge_force.

Restore SHMEM_HUGE_DENY precedence over MADV_COLLAPSE.

Link: https://lkml.kernel.org/r/20221224082035.3197140-2-zokeefe@google.com
Fixes: 7c6c6cc4d3 ("mm/shmem: add flag to enforce shmem THP in hugepage_vma_check()")
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:33 +01:00
Liam Howlett
e733121383 nommu: fix split_vma() map_count error
commit fd9edbdbdcde6b489ce59f326755ef16a2ffadd7 upstream.

During the maple tree conversion of nommu, an error in counting the VMAs
was introduced by counting the existing VMA again.  The counting used to
be decremented by one and incremented by two, but now it only increments
by two.  Fix the counting error by moving the increment outside the
setup_vma_to_mm() function to the callers.

Link: https://lkml.kernel.org/r/20230109205809.956325-1-Liam.Howlett@oracle.com
Fixes: 8220543df1 ("nommu: remove uses of VMA linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:33 +01:00
Liam Howlett
6447569f4f nommu: fix do_munmap() error path
commit 80be727ec87225797771a39f3e6801baf291faaf upstream.

When removing a VMA from the tree fails due to no memory, do not free the
VMA since a reference still exists.

Link: https://lkml.kernel.org/r/20230109205708.956103-1-Liam.Howlett@oracle.com
Fixes: 8220543df1 ("nommu: remove uses of VMA linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:33 +01:00
Liam Howlett
1442d51026 nommu: fix memory leak in do_mmap() error path
commit 7f31cced5724e6d414fe750aa1cd7e7b578ec22f upstream.

The preallocation of the maple tree nodes may leak if the error path to
"error_just_free" is taken.  Fix this by moving the freeing of the maple
tree nodes to a shared location for all error paths.

Link: https://lkml.kernel.org/r/20230109205507.955577-1-Liam.Howlett@oracle.com
Fixes: 8220543df1 ("nommu: remove uses of VMA linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:33 +01:00
Aaron Thompson
68a6f7dbf8 mm: Always release pages to the buddy allocator in memblock_free_late().
commit 115d9d77bb0f9152c60b6e8646369fa7f6167593 upstream.

If CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, memblock_free_pages()
only releases pages to the buddy allocator if they are not in the
deferred range. This is correct for free pages (as defined by
for_each_free_mem_pfn_range_in_zone()) because free pages in the
deferred range will be initialized and released as part of the deferred
init process. memblock_free_pages() is called by memblock_free_late(),
which is used to free reserved ranges after memblock_free_all() has
run. All pages in reserved ranges have been initialized at that point,
and accordingly, those pages are not touched by the deferred init
process. This means that currently, if the pages that
memblock_free_late() intends to release are in the deferred range, they
will never be released to the buddy allocator. They will forever be
reserved.

In addition, memblock_free_pages() calls kmsan_memblock_free_pages(),
which is also correct for free pages but is not correct for reserved
pages. KMSAN metadata for reserved pages is initialized by
kmsan_init_shadow(), which runs shortly before memblock_free_all().

For both of these reasons, memblock_free_pages() should only be called
for free pages, and memblock_free_late() should call __free_pages_core()
directly instead.

One case where this issue can occur in the wild is EFI boot on
x86_64. The x86 EFI code reserves all EFI boot services memory ranges
via memblock_reserve() and frees them later via memblock_free_late()
(efi_reserve_boot_services() and efi_free_boot_services(),
respectively). If any of those ranges happens to fall within the
deferred init range, the pages will not be released and that memory will
be unavailable.

For example, on an Amazon EC2 t3.micro VM (1 GB) booting via EFI:

v6.2-rc2:
  # grep -E 'Node|spanned|present|managed' /proc/zoneinfo
  Node 0, zone      DMA
          spanned  4095
          present  3999
          managed  3840
  Node 0, zone    DMA32
          spanned  246652
          present  245868
          managed  178867

v6.2-rc2 + patch:
  # grep -E 'Node|spanned|present|managed' /proc/zoneinfo
  Node 0, zone      DMA
          spanned  4095
          present  3999
          managed  3840
  Node 0, zone    DMA32
          spanned  246652
          present  245868
          managed  222816   # +43,949 pages

Fixes: 3a80a7fa79 ("mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set")
Signed-off-by: Aaron Thompson <dev@aaront.org>
Link: https://lore.kernel.org/r/01010185892de53e-e379acfb-7044-4b24-b30a-e2657c1ba989-000000@us-west-2.amazonses.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:58:20 +01:00
Mike Kravetz
17183187dc hugetlb: really allocate vma lock for all sharable vmas
commit e700898fa075c69b3ae02b702ab57fb75e1a82ec upstream.

Commit bbff39cc6c ("hugetlb: allocate vma lock for all sharable vmas")
removed the pmd sharable checks in the vma lock helper routines.  However,
it left the functional version of helper routines behind #ifdef
CONFIG_ARCH_WANT_HUGE_PMD_SHARE.  Therefore, the vma lock is not being
used for sharable vmas on architectures that do not support pmd sharing.
On these architectures, a potential fault/truncation race is exposed that
could leave pages in a hugetlb file past i_size until the file is removed.

Move the functional vma lock helpers outside the ifdef, and remove the
non-functional stubs.  Since the vma lock is not just for pmd sharing,
rename the routine __vma_shareable_flags_pmd.

Link: https://lkml.kernel.org/r/20221212235042.178355-1-mike.kravetz@oracle.com
Fixes: bbff39cc6c ("hugetlb: allocate vma lock for all sharable vmas")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-07 11:11:55 +01:00
NARIBAYASHI Akira
b3b3212725 mm, compaction: fix fast_isolate_around() to stay within boundaries
commit be21b32afe470c5ae98e27e49201158a47032942 upstream.

Depending on the memory configuration, isolate_freepages_block() may scan
pages out of the target range and causes panic.

Panic can occur on systems with multiple zones in a single pageblock.

The reason it is rare is that it only happens in special
configurations.  Depending on how many similar systems there are, it
may be a good idea to fix this problem for older kernels as well.

The problem is that pfn as argument of fast_isolate_around() could be out
of the target range.  Therefore we should consider the case where pfn <
start_pfn, and also the case where end_pfn < pfn.

This problem should have been addressd by the commit 6e2b7044c1 ("mm,
compaction: make fast_isolate_freepages() stay within zone") but there was
an oversight.

 Case1: pfn < start_pfn

  <at memory compaction for node Y>
  |  node X's zone  | node Y's zone
  +-----------------+------------------------------...
   pageblock    ^   ^     ^
  +-----------+-----------+-----------+-----------+...
                ^   ^     ^
                ^   ^      end_pfn
                ^    start_pfn = cc->zone->zone_start_pfn
                 pfn
                <---------> scanned range by "Scan After"

 Case2: end_pfn < pfn

  <at memory compaction for node X>
  |  node X's zone  | node Y's zone
  +-----------------+------------------------------...
   pageblock  ^     ^   ^
  +-----------+-----------+-----------+-----------+...
              ^     ^   ^
              ^     ^    pfn
              ^      end_pfn
               start_pfn
              <---------> scanned range by "Scan Before"

It seems that there is no good reason to skip nr_isolated pages just after
given pfn.  So let perform simple scan from start to end instead of
dividing the scan into "Before" and "After".

Link: https://lkml.kernel.org/r/20221026112438.236336-1-a.naribayashi@fujitsu.com
Fixes: 6e2b7044c1 ("mm, compaction: make fast_isolate_freepages() stay within zone").
Signed-off-by: NARIBAYASHI Akira <a.naribayashi@fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-04 11:29:01 +01:00
Arnd Bergmann
2cec280c49 kmsan: include linux/vmalloc.h
commit aaa746ad8b30f38ef89a301faf339ef1c19cf33a upstream.

This is needed for the vmap/vunmap declarations:

mm/kmsan/kmsan_test.c:316:9: error: implicit declaration of function 'vmap' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        vbuf = vmap(pages, npages, VM_MAP, PAGE_KERNEL);
               ^
mm/kmsan/kmsan_test.c:316:29: error: use of undeclared identifier 'VM_MAP'
        vbuf = vmap(pages, npages, VM_MAP, PAGE_KERNEL);
                                   ^
mm/kmsan/kmsan_test.c:322:3: error: implicit declaration of function 'vunmap' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                vunmap(vbuf);
                ^

Link: https://lkml.kernel.org/r/20221215163046.4079767-1-arnd@kernel.org
Fixes: 8ed691b02a ("kmsan: add tests for KMSAN")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-04 11:28:59 +01:00
Arnd Bergmann
dace33a189 kmsan: export kmsan_handle_urb
commit 7ba594d700998bafa96a75360d2e060aa39156d2 upstream.

USB support can be in a loadable module, and this causes a link failure
with KMSAN:

ERROR: modpost: "kmsan_handle_urb" [drivers/usb/core/usbcore.ko] undefined!

Export the symbol so it can be used by this module.

Link: https://lkml.kernel.org/r/20221215162710.3802378-1-arnd@kernel.org
Fixes: 553a80188a ("kmsan: handle memory sent to/from USB")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-04 11:28:59 +01:00
Mathieu Desnoyers
0ce4cc6d26 mm/mempolicy: fix memory leak in set_mempolicy_home_node system call
commit 38ce7c9bdfc228c14d7621ba36d3eebedd9d4f76 upstream.

When encountering any vma in the range with policy other than MPOL_BIND or
MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put on
the policy just allocated with mpol_dup().

This allows arbitrary users to leak kernel memory.

Link: https://lkml.kernel.org/r/20221215194621.202816-1-mathieu.desnoyers@efficios.com
Fixes: c6018b4b25 ("mm/mempolicy: add set_mempolicy_home_node syscall")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: <stable@vger.kernel.org>	[5.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-04 11:28:59 +01:00
Vlastimil Babka
4d528dab40 mm, mremap: fix mremap() expanding vma with addr inside vma
commit 6f12be792fde994ed934168f93c2a0d2a0cf0bc5 upstream.

Since 6.1 we have noticed random rpm install failures that were tracked to
mremap() returning -ENOMEM and to commit ca3d76b0aa ("mm: add merging
after mremap resize").

The problem occurs when mremap() expands a VMA in place, but using an
starting address that's not vma->vm_start, but somewhere in the middle.
The extension_pgoff calculation introduced by the commit is wrong in that
case, so vma_merge() fails due to pgoffs not being compatible.  Fix the
calculation.

By the way it seems that the situations, where rpm now expands a vma from
the middle, were made possible also due to that commit, thanks to the
improved vma merging.  Yet it should work just fine, except for the buggy
calculation.

Link: https://lkml.kernel.org/r/20221216163227.24648-1-vbabka@suse.cz
Reported-by: Jiri Slaby <jirislaby@kernel.org>
  Link: https://bugzilla.suse.com/show_bug.cgi?id=1206359
Fixes: ca3d76b0aa ("mm: add merging after mremap resize")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jakub Matěna <matenajakub@gmail.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-04 11:28:59 +01:00
David Hildenbrand
5cfb9a60ed mm/gup: disallow FOLL_FORCE|FOLL_WRITE on hugetlb mappings
commit f347454d034184b4f0a2caf6e14daf7848cea01c upstream.

hugetlb does not support fake write-faults (write faults without write
permissions).  However, we are currently able to trigger a
FAULT_FLAG_WRITE fault on a VMA without VM_WRITE.

If we'd ever want to support FOLL_FORCE|FOLL_WRITE, we'd have to teach
hugetlb to:

(1) Leave the page mapped R/O after the fake write-fault, like
    maybe_mkwrite() does.
(2) Allow writing to an exclusive anon page that's mapped R/O when
    FOLL_FORCE is set, like can_follow_write_pte(). E.g.,
    __follow_hugetlb_must_fault() needs adjustment.

For now, it's not clear if that added complexity is really required.
History tolds us that FOLL_FORCE is dangerous and that we better limit its
use to a bare minimum.

--------------------------------------------------------------------------
  #include <stdio.h>
  #include <stdlib.h>
  #include <fcntl.h>
  #include <unistd.h>
  #include <errno.h>
  #include <stdint.h>
  #include <sys/mman.h>
  #include <linux/mman.h>

  int main(int argc, char **argv)
  {
          char *map;
          int mem_fd;

          map = mmap(NULL, 2 * 1024 * 1024u, PROT_READ,
                     MAP_PRIVATE|MAP_ANON|MAP_HUGETLB|MAP_HUGE_2MB, -1, 0);
          if (map == MAP_FAILED) {
                  fprintf(stderr, "mmap() failed: %d\n", errno);
                  return 1;
          }

          mem_fd = open("/proc/self/mem", O_RDWR);
          if (mem_fd < 0) {
                  fprintf(stderr, "open(/proc/self/mem) failed: %d\n", errno);
                  return 1;
          }

          if (pwrite(mem_fd, "0", 1, (uintptr_t) map) == 1) {
                  fprintf(stderr, "write() succeeded, which is unexpected\n");
                  return 1;
          }

          printf("write() failed as expected: %d\n", errno);
          return 0;
  }
--------------------------------------------------------------------------

Fortunately, we have a sanity check in hugetlb_wp() in place ever since
commit 1d8d14641f ("mm/hugetlb: support write-faults in shared
mappings"), that bails out instead of silently mapping a page writable in
a !PROT_WRITE VMA.

Consequently, above reproducer triggers a warning, similar to the one
reported by szsbot:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 3612 at mm/hugetlb.c:5313 hugetlb_wp+0x20a/0x1af0 mm/hugetlb.c:5313
Modules linked in:
CPU: 1 PID: 3612 Comm: syz-executor250 Not tainted 6.1.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
RIP: 0010:hugetlb_wp+0x20a/0x1af0 mm/hugetlb.c:5313
Code: ea 03 80 3c 02 00 0f 85 31 14 00 00 49 8b 5f 20 31 ff 48 89 dd 83 e5 02 48 89 ee e8 70 ab b7 ff 48 85 ed 75 5b e8 76 ae b7 ff <0f> 0b 41 bd 40 00 00 00 e8 69 ae b7 ff 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc90003caf620 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000008640070 RCX: 0000000000000000
RDX: ffff88807b963a80 RSI: ffffffff81c4ed2a RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000008c07e R12: ffff888023805800
R13: 0000000000000000 R14: ffffffff91217f38 R15: ffff88801d4b0360
FS:  0000555555bba300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff7a47a1b8 CR3: 000000002378d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 hugetlb_no_page mm/hugetlb.c:5755 [inline]
 hugetlb_fault+0x19cc/0x2060 mm/hugetlb.c:5874
 follow_hugetlb_page+0x3f3/0x1850 mm/hugetlb.c:6301
 __get_user_pages+0x2cb/0xf10 mm/gup.c:1202
 __get_user_pages_locked mm/gup.c:1434 [inline]
 __get_user_pages_remote+0x18f/0x830 mm/gup.c:2187
 get_user_pages_remote+0x84/0xc0 mm/gup.c:2260
 __access_remote_vm+0x287/0x6b0 mm/memory.c:5517
 ptrace_access_vm+0x181/0x1d0 kernel/ptrace.c:61
 generic_ptrace_pokedata kernel/ptrace.c:1323 [inline]
 ptrace_request+0xb46/0x10c0 kernel/ptrace.c:1046
 arch_ptrace+0x36/0x510 arch/x86/kernel/ptrace.c:828
 __do_sys_ptrace kernel/ptrace.c:1296 [inline]
 __se_sys_ptrace kernel/ptrace.c:1269 [inline]
 __x64_sys_ptrace+0x178/0x2a0 kernel/ptrace.c:1269
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
[...]

So let's silence that warning by teaching GUP code that FOLL_FORCE -- so
far -- does not apply to hugetlb.

Note that FOLL_FORCE for read-access seems to be working as expected.  The
assumption is that this has been broken forever, only ever since above
commit, we actually detect the wrong handling and WARN_ON_ONCE().

I assume this has been broken at least since 2014, when mm/gup.c came to
life.  I failed to come up with a suitable Fixes tag quickly.

Link: https://lkml.kernel.org/r/20221031152524.173644-1-david@redhat.com
Fixes: 1d8d14641f ("mm/hugetlb: support write-faults in shared mappings")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: <syzbot+f0b97304ef90f0d0b1dc@syzkaller.appspotmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:11 +01:00
Linus Torvalds
4cee37b3a4 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address
post-6.0 issues.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY5Ur2AAKCRDdBJ7gKXxA
 jsGmAQDWSq6z9fVgk30XpMr/X7t5c6NTPw5GocVpdwG8iqch3gEAjEs5/Kcd/mx4
 d1dLaJFu1u3syessp8nJrNr1HANIog8=
 =L8zu
 -----END PGP SIGNATURE-----

Merge tag 'mm-hotfixes-stable-2022-12-10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "Nine hotfixes.

  Six for MM, three for other areas. Four of these patches address
  post-6.0 issues"

* tag 'mm-hotfixes-stable-2022-12-10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  memcg: fix possible use-after-free in memcg_write_event_control()
  MAINTAINERS: update Muchun Song's email
  mm/gup: fix gup_pud_range() for dax
  mmap: fix do_brk_flags() modifying obviously incorrect VMAs
  mm/swap: fix SWP_PFN_BITS with CONFIG_PHYS_ADDR_T_64BIT on 32bit
  tmpfs: fix data loss from failed fallocate
  kselftests: cgroup: update kmem test precision tolerance
  mm: do not BUG_ON missing brk mapping, because userspace can unmap it
  mailmap: update Matti Vaittinen's email address
2022-12-10 17:10:52 -08:00
Tejun Heo
4a7ba45b1a memcg: fix possible use-after-free in memcg_write_event_control()
memcg_write_event_control() accesses the dentry->d_name of the specified
control fd to route the write call.  As a cgroup interface file can't be
renamed, it's safe to access d_name as long as the specified file is a
regular cgroup file.  Also, as these cgroup interface files can't be
removed before the directory, it's safe to access the parent too.

Prior to 347c4a8747 ("memcg: remove cgroup_event->cft"), there was a
call to __file_cft() which verified that the specified file is a regular
cgroupfs file before further accesses.  The cftype pointer returned from
__file_cft() was no longer necessary and the commit inadvertently dropped
the file type check with it allowing any file to slip through.  With the
invarients broken, the d_name and parent accesses can now race against
renames and removals of arbitrary files and cause use-after-free's.

Fix the bug by resurrecting the file type check in __file_cft().  Now that
cgroupfs is implemented through kernfs, checking the file operations needs
to go through a layer of indirection.  Instead, let's check the superblock
and dentry type.

Link: https://lkml.kernel.org/r/Y5FRm/cfcKPGzWwl@slm.duckdns.org
Fixes: 347c4a8747 ("memcg: remove cgroup_event->cft")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jann Horn <jannh@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>	[3.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-09 18:41:17 -08:00
John Starks
fcd0ccd836 mm/gup: fix gup_pud_range() for dax
For dax pud, pud_huge() returns true on x86. So the function works as long
as hugetlb is configured. However, dax doesn't depend on hugetlb.
Commit 414fd080d1 ("mm/gup: fix gup_pmd_range() for dax") fixed
devmap-backed huge PMDs, but missed devmap-backed huge PUDs. Fix this as
well.

This fixes the below kernel panic:

general protection fault, probably for non-canonical address 0x69e7c000cc478: 0000 [#1] SMP
	< snip >
Call Trace:
<TASK>
get_user_pages_fast+0x1f/0x40
iov_iter_get_pages+0xc6/0x3b0
? mempool_alloc+0x5d/0x170
bio_iov_iter_get_pages+0x82/0x4e0
? bvec_alloc+0x91/0xc0
? bio_alloc_bioset+0x19a/0x2a0
blkdev_direct_IO+0x282/0x480
? __io_complete_rw_common+0xc0/0xc0
? filemap_range_has_page+0x82/0xc0
generic_file_direct_write+0x9d/0x1a0
? inode_update_time+0x24/0x30
__generic_file_write_iter+0xbd/0x1e0
blkdev_write_iter+0xb4/0x150
? io_import_iovec+0x8d/0x340
io_write+0xf9/0x300
io_issue_sqe+0x3c3/0x1d30
? sysvec_reschedule_ipi+0x6c/0x80
__io_queue_sqe+0x33/0x240
? fget+0x76/0xa0
io_submit_sqes+0xe6a/0x18d0
? __fget_light+0xd1/0x100
__x64_sys_io_uring_enter+0x199/0x880
? __context_tracking_enter+0x1f/0x70
? irqentry_exit_to_user_mode+0x24/0x30
? irqentry_exit+0x1d/0x30
? __context_tracking_exit+0xe/0x70
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc97c11a7be
	< snip >
</TASK>
---[ end trace 48b2e0e67debcaeb ]---
RIP: 0010:internal_get_user_pages_fast+0x340/0x990
	< snip >
Kernel panic - not syncing: Fatal exception
Kernel Offset: disabled

Link: https://lkml.kernel.org/r/1670392853-28252-1-git-send-email-ssengar@linux.microsoft.com
Fixes: 414fd080d1 ("mm/gup: fix gup_pmd_range() for dax")
Signed-off-by: John Starks <jostarks@microsoft.com>
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-09 18:41:17 -08:00
Liam Howlett
6c28ca6485 mmap: fix do_brk_flags() modifying obviously incorrect VMAs
Add more sanity checks to the VMA that do_brk_flags() will expand.  Ensure
the VMA matches basic merge requirements within the function before
calling can_vma_merge_after().

Drop the duplicate checks from vm_brk_flags() since they will be enforced
later.

The old code would expand file VMAs on brk(), which is functionally
wrong and also dangerous in terms of locking because the brk() path
isn't designed for file VMAs and therefore doesn't lock the file
mapping.  Checking can_vma_merge_after() ensures that new anonymous
VMAs can't be merged into file VMAs.

See https://lore.kernel.org/linux-mm/CAG48ez1tJZTOjS_FjRZhvtDA-STFmdw8PEizPDwMGFd_ui0Nrw@mail.gmail.com/

Link: https://lkml.kernel.org/r/20221205192304.1957418-1-Liam.Howlett@oracle.com
Fixes: 2e7ce7d354 ("mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Jann Horn <jannh@google.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-09 18:41:16 -08:00
Hugh Dickins
44bcabd70c tmpfs: fix data loss from failed fallocate
Fix tmpfs data loss when the fallocate system call is interrupted by a
signal, or fails for some other reason.  The partial folio handling in
shmem_undo_range() forgot to consider this unfalloc case, and was liable
to erase or truncate out data which had already been committed earlier.

It turns out that none of the partial folio handling there is appropriate
for the unfalloc case, which just wants to proceed to removal of whole
folios: which find_get_entries() provides, even when partially covered.

Original patch by Rui Wang.

Link: https://lore.kernel.org/linux-mm/33b85d82.7764.1842e9ab207.Coremail.chenguoqic@163.com/
Link: https://lkml.kernel.org/r/a5dac112-cf4b-7af-a33-f386e347fd38@google.com
Fixes: b9a8a4195c ("truncate,shmem: Handle truncates that split large folios")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Guoqi Chen <chenguoqic@163.com>
  Link: https://lore.kernel.org/all/20221101032248.819360-1-kernel@hev.cc/
Cc: Rui Wang <kernel@hev.cc>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: <stable@vger.kernel.org>	[5.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-09 18:41:16 -08:00
Jason A. Donenfeld
f5ad508340 mm: do not BUG_ON missing brk mapping, because userspace can unmap it
The following program will trigger the BUG_ON that this patch removes,
because the user can munmap() mm->brk:

  #include <sys/syscall.h>
  #include <sys/mman.h>
  #include <assert.h>
  #include <unistd.h>

  static void *brk_now(void)
  {
    return (void *)syscall(SYS_brk, 0);
  }

  static void brk_set(void *b)
  {
    assert(syscall(SYS_brk, b) != -1);
  }

  int main(int argc, char *argv[])
  {
    void *b = brk_now();
    brk_set(b + 4096);
    assert(munmap(b - 4096, 4096 * 2) == 0);
    brk_set(b);
    return 0;
  }

Compile that with musl, since glibc actually uses brk(), and then
execute it, and it'll hit this splat:

  kernel BUG at mm/mmap.c:229!
  invalid opcode: 0000 [#1] PREEMPT SMP
  CPU: 12 PID: 1379 Comm: a.out Tainted: G S   U             6.1.0-rc7+ #419
  RIP: 0010:__do_sys_brk+0x2fc/0x340
  Code: 00 00 4c 89 ef e8 04 d3 fe ff eb 9a be 01 00 00 00 4c 89 ff e8 35 e0 fe ff e9 6e ff ff ff 4d 89 a7 20>
  RSP: 0018:ffff888140bc7eb0 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 00000000007e7000 RCX: ffff8881020fe000
  RDX: ffff8881020fe001 RSI: ffff8881955c9b00 RDI: ffff8881955c9b08
  RBP: 0000000000000000 R08: ffff8881955c9b00 R09: 00007ffc77844000
  R10: 0000000000000000 R11: 0000000000000001 R12: 00000000007e8000
  R13: 00000000007e8000 R14: 00000000007e7000 R15: ffff8881020fe000
  FS:  0000000000604298(0000) GS:ffff88901f700000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000603fe0 CR3: 000000015ba9a005 CR4: 0000000000770ee0
  PKRU: 55555554
  Call Trace:
   <TASK>
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
  RIP: 0033:0x400678
  Code: 10 4c 8d 41 08 4c 89 44 24 10 4c 8b 01 8b 4c 24 08 83 f9 2f 77 0a 4c 8d 4c 24 20 4c 01 c9 eb 05 48 8b>
  RSP: 002b:00007ffc77863890 EFLAGS: 00000212 ORIG_RAX: 000000000000000c
  RAX: ffffffffffffffda RBX: 000000000040031b RCX: 0000000000400678
  RDX: 00000000004006a1 RSI: 00000000007e6000 RDI: 00000000007e7000
  RBP: 00007ffc77863900 R08: 0000000000000000 R09: 00000000007e6000
  R10: 00007ffc77863930 R11: 0000000000000212 R12: 00007ffc77863978
  R13: 00007ffc77863988 R14: 0000000000000000 R15: 0000000000000000
   </TASK>

Instead, just return the old brk value if the original mapping has been
removed.

[akpm@linux-foundation.org: fix changelog, per Liam]
Link: https://lkml.kernel.org/r/20221202162724.2009-1-Jason@zx2c4.com
Fixes: 2e7ce7d354 ("mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-09 18:41:16 -08:00
Tejun Heo
fbf8321238 memcg: Fix possible use-after-free in memcg_write_event_control()
memcg_write_event_control() accesses the dentry->d_name of the specified
control fd to route the write call.  As a cgroup interface file can't be
renamed, it's safe to access d_name as long as the specified file is a
regular cgroup file.  Also, as these cgroup interface files can't be
removed before the directory, it's safe to access the parent too.

Prior to 347c4a8747 ("memcg: remove cgroup_event->cft"), there was a
call to __file_cft() which verified that the specified file is a regular
cgroupfs file before further accesses.  The cftype pointer returned from
__file_cft() was no longer necessary and the commit inadvertently
dropped the file type check with it allowing any file to slip through.
With the invarients broken, the d_name and parent accesses can now race
against renames and removals of arbitrary files and cause
use-after-free's.

Fix the bug by resurrecting the file type check in __file_cft().  Now
that cgroupfs is implemented through kernfs, checking the file
operations needs to go through a layer of indirection.  Instead, let's
check the superblock and dentry type.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 347c4a8747 ("memcg: remove cgroup_event->cft")
Cc: stable@kernel.org # v3.14+
Reported-by: Jann Horn <jannh@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-12-08 10:40:58 -08:00
Linus Torvalds
0ba09b1733 Revert "mm: align larger anonymous mappings on THP boundaries"
This reverts commit f35b5d7d67.

It has been reported to cause huge performance regressions on some loads
(will-it-scale.per_process_ops, but also building the kernel with
clang).

The commit did speed up gcc builds by a small amount, so it's not an
unambiguous regression, but until the big regressions are understood,
let's revert it.

Reported-by: kernel test robot <yujie.liu@intel.com>
Link: https://lore.kernel.org/r/202210181535.7144dd15-yujie.liu@intel.com
Reported-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/lkml/Y1DNQaoPWxE%2BrGce@dev-arch.thelio-3990X/
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-12-04 12:51:59 -08:00
Linus Torvalds
bdaa78c6aa 15 hotfixes. 11 marked cc:stable. Only three or four of the latter
address post-6.0 issues, which is hopefully a sign that things are
 converging.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY4pQpQAKCRDdBJ7gKXxA
 jquxAP9Lqif7CGDgdq8uWY2hHS/Ujc3k7Ohgyzs37olnCuU8KwEA6/J7SpjsBgtY
 OfzvnwxpCTh8Kfzu/oNckIHo/EEiIA8=
 =o6qT
 -----END PGP SIGNATURE-----

Merge tag 'mm-hotfixes-stable-2022-12-02' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "15 hotfixes,  11 marked cc:stable.

  Only three or four of the latter address post-6.0 issues, which is
  hopefully a sign that things are converging"

* tag 'mm-hotfixes-stable-2022-12-02' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  revert "kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible"
  Kconfig.debug: provide a little extra FRAME_WARN leeway when KASAN is enabled
  drm/amdgpu: temporarily disable broken Clang builds due to blown stack-frame
  mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths
  mm/khugepaged: fix GUP-fast interaction by sending IPI
  mm/khugepaged: take the right locks for page table retraction
  mm: migrate: fix THP's mapcount on isolation
  mm: introduce arch_has_hw_nonleaf_pmd_young()
  mm: add dummy pmd_young() for architectures not having it
  mm/damon/sysfs: fix wrong empty schemes assumption under online tuning in damon_sysfs_set_schemes()
  tools/vm/slabinfo-gnuplot: use "grep -E" instead of "egrep"
  nilfs2: fix NULL pointer dereference in nilfs_palloc_commit_free_entry()
  hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing
  madvise: use zap_page_range_single for madvise dontneed
  mm: replace VM_WARN_ON to pr_warn if the node is offline with __GFP_THISNODE
2022-12-02 13:39:38 -08:00
Jann Horn
f268f6cf87 mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths
Any codepath that zaps page table entries must invoke MMU notifiers to
ensure that secondary MMUs (like KVM) don't keep accessing pages which
aren't mapped anymore.  Secondary MMUs don't hold their own references to
pages that are mirrored over, so failing to notify them can lead to page
use-after-free.

I'm marking this as addressing an issue introduced in commit f3f0e1d215
("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of
the security impact of this only came in commit 27e1f82731 ("khugepaged:
enable collapse pmd for pte-mapped THP"), which actually omitted flushes
for the removal of present PTEs, not just for the removal of empty page
tables.

Link: https://lkml.kernel.org/r/20221129154730.2274278-3-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-3-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-3-jannh@google.com
Fixes: f3f0e1d215 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:42 -08:00
Jann Horn
2ba99c5e08 mm/khugepaged: fix GUP-fast interaction by sending IPI
Since commit 70cbc3cc78 ("mm: gup: fix the fast GUP race against THP
collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to
ensure that the page table was not removed by khugepaged in between.

However, lockless_pages_from_mm() still requires that the page table is
not concurrently freed.  Fix it by sending IPIs (if the architecture uses
semi-RCU-style page table freeing) before freeing/reusing page tables.

Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com
Fixes: ba76149f47 ("thp: khugepaged")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:42 -08:00
Jann Horn
8d3c106e19 mm/khugepaged: take the right locks for page table retraction
pagetable walks on address ranges mapped by VMAs can be done under the
mmap lock, the lock of an anon_vma attached to the VMA, or the lock of the
VMA's address_space.  Only one of these needs to be held, and it does not
need to be held in exclusive mode.

Under those circumstances, the rules for concurrent access to page table
entries are:

 - Terminal page table entries (entries that don't point to another page
   table) can be arbitrarily changed under the page table lock, with the
   exception that they always need to be consistent for
   hardware page table walks and lockless_pages_from_mm().
   This includes that they can be changed into non-terminal entries.
 - Non-terminal page table entries (which point to another page table)
   can not be modified; readers are allowed to READ_ONCE() an entry, verify
   that it is non-terminal, and then assume that its value will stay as-is.

Retracting a page table involves modifying a non-terminal entry, so
page-table-level locks are insufficient to protect against concurrent page
table traversal; it requires taking all the higher-level locks under which
it is possible to start a page walk in the relevant range in exclusive
mode.

The collapse_huge_page() path for anonymous THP already follows this rule,
but the shmem/file THP path was getting it wrong, making it possible for
concurrent rmap-based operations to cause corruption.

Link: https://lkml.kernel.org/r/20221129154730.2274278-1-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-1-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-1-jannh@google.com
Fixes: 27e1f82731 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:42 -08:00
Gavin Shan
829ae0f81c mm: migrate: fix THP's mapcount on isolation
The issue is reported when removing memory through virtio_mem device.  The
transparent huge page, experienced copy-on-write fault, is wrongly
regarded as pinned.  The transparent huge page is escaped from being
isolated in isolate_migratepages_block().  The transparent huge page can't
be migrated and the corresponding memory block can't be put into offline
state.

Fix it by replacing page_mapcount() with total_mapcount().  With this, the
transparent huge page can be isolated and migrated, and the memory block
can be put into offline state.  Besides, The page's refcount is increased
a bit earlier to avoid the page is released when the check is executed.

Link: https://lkml.kernel.org/r/20221124095523.31061-1-gshan@redhat.com
Fixes: 1da2f328fa ("mm,thp,compaction,cma: allow THP migration for CMA allocations")
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reported-by: Zhenyu Zhang <zhenyzha@redhat.com>
Tested-by: Zhenyu Zhang <zhenyzha@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>	[5.7+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:41 -08:00
Juergen Gross
4aaf269c76 mm: introduce arch_has_hw_nonleaf_pmd_young()
When running as a Xen PV guests commit eed9a328aa ("mm: x86: add
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG") can cause a protection violation in
pmdp_test_and_clear_young():

 BUG: unable to handle page fault for address: ffff8880083374d0
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0003) - permissions violation
 PGD 3026067 P4D 3026067 PUD 3027067 PMD 7fee5067 PTE 8010000008337065
 Oops: 0003 [#1] PREEMPT SMP NOPTI
 CPU: 7 PID: 158 Comm: kswapd0 Not tainted 6.1.0-rc5-20221118-doflr+ #1
 RIP: e030:pmdp_test_and_clear_young+0x25/0x40

This happens because the Xen hypervisor can't emulate direct writes to
page table entries other than PTEs.

This can easily be fixed by introducing arch_has_hw_nonleaf_pmd_young()
similar to arch_has_hw_pte_young() and test that instead of
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG.

Link: https://lkml.kernel.org/r/20221123064510.16225-1-jgross@suse.com
Fixes: eed9a328aa ("mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: Yu Zhao <yuzhao@google.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: David Hildenbrand <david@redhat.com>	[core changes]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:41 -08:00
SeongJae Park
95bc35f9be mm/damon/sysfs: fix wrong empty schemes assumption under online tuning in damon_sysfs_set_schemes()
Commit da87878010 ("mm/damon/sysfs: support online inputs update") made
'damon_sysfs_set_schemes()' to be called for running DAMON context, which
could have schemes.  In the case, DAMON sysfs interface is supposed to
update, remove, or add schemes to reflect the sysfs files.  However, the
code is assuming the DAMON context wouldn't have schemes at all, and
therefore creates and adds new schemes.  As a result, the code doesn't
work as intended for online schemes tuning and could have more than
expected memory footprint.  The schemes are all in the DAMON context, so
it doesn't leak the memory, though.

Remove the wrong asssumption (the DAMON context wouldn't have schemes) in
'damon_sysfs_set_schemes()' to fix the bug.

Link: https://lkml.kernel.org/r/20221122194831.3472-1-sj@kernel.org
Fixes: da87878010 ("mm/damon/sysfs: support online inputs update")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:41 -08:00
Mike Kravetz
04ada095dc hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing
madvise(MADV_DONTNEED) ends up calling zap_page_range() to clear page
tables associated with the address range.  For hugetlb vmas,
zap_page_range will call __unmap_hugepage_range_final.  However,
__unmap_hugepage_range_final assumes the passed vma is about to be removed
and deletes the vma_lock to prevent pmd sharing as the vma is on the way
out.  In the case of madvise(MADV_DONTNEED) the vma remains, but the
missing vma_lock prevents pmd sharing and could potentially lead to issues
with truncation/fault races.

This issue was originally reported here [1] as a BUG triggered in
page_try_dup_anon_rmap.  Prior to the introduction of the hugetlb
vma_lock, __unmap_hugepage_range_final cleared the VM_MAYSHARE flag to
prevent pmd sharing.  Subsequent faults on this vma were confused as
VM_MAYSHARE indicates a sharable vma, but was not set so page_mapping was
not set in new pages added to the page table.  This resulted in pages that
appeared anonymous in a VM_SHARED vma and triggered the BUG.

Address issue by adding a new zap flag ZAP_FLAG_UNMAP to indicate an unmap
call from unmap_vmas().  This is used to indicate the 'final' unmapping of
a hugetlb vma.  When called via MADV_DONTNEED, this flag is not set and
the vm_lock is not deleted.

[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/

Link: https://lkml.kernel.org/r/20221114235507.294320-3-mike.kravetz@oracle.com
Fixes: 90e7e7f5ef ("mm: enable MADV_DONTNEED for hugetlb mappings")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Wei Chen <harperchen1110@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:40 -08:00
Mike Kravetz
21b85b0952 madvise: use zap_page_range_single for madvise dontneed
This series addresses the issue first reported in [1], and fully described
in patch 2.  Patches 1 and 2 address the user visible issue and are tagged
for stable backports.

While exploring solutions to this issue, related problems with mmu
notification calls were discovered.  This is addressed in the patch
"hugetlb: remove duplicate mmu notifications:".  Since there are no user
visible effects, this third is not tagged for stable backports.

Previous discussions suggested further cleanup by removing the
routine zap_page_range.  This is possible because zap_page_range_single
is now exported, and all callers of zap_page_range pass ranges entirely
within a single vma.  This work will be done in a later patch so as not
to distract from this bug fix.

[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/


This patch (of 2):

Expose the routine zap_page_range_single to zap a range within a single
vma.  The madvise routine madvise_dontneed_single_vma can use this routine
as it explicitly operates on a single vma.  Also, update the mmu
notification range in zap_page_range_single to take hugetlb pmd sharing
into account.  This is required as MADV_DONTNEED supports hugetlb vmas.

Link: https://lkml.kernel.org/r/20221114235507.294320-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20221114235507.294320-2-mike.kravetz@oracle.com
Fixes: 90e7e7f5ef ("mm: enable MADV_DONTNEED for hugetlb mappings")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Wei Chen <harperchen1110@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:40 -08:00
Linus Torvalds
0b1dcc2cf5 24 hotfixes. 8 marked cc:stable and 16 for post-6.0 issues.
There have been a lot of hotfixes this cycle, and this is quite a large
 batch given how far we are into the -rc cycle.  Presumably a reflection of
 the unusually large amount of MM material which went into 6.1-rc1.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY4Bd6gAKCRDdBJ7gKXxA
 jvX6AQCsG1ld24kMpdD+70XXUyC29g/6/jribgtZApHyDYjxSwD/WmLNpPlUPRax
 WB071Y5w65vjSTUKvwU0OLGbHwyxgAw=
 =swD5
 -----END PGP SIGNATURE-----

Merge tag 'mm-hotfixes-stable-2022-11-24' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull hotfixes from Andrew Morton:
 "24 MM and non-MM hotfixes. 8 marked cc:stable and 16 for post-6.0
  issues.

  There have been a lot of hotfixes this cycle, and this is quite a
  large batch given how far we are into the -rc cycle. Presumably a
  reflection of the unusually large amount of MM material which went
  into 6.1-rc1"

* tag 'mm-hotfixes-stable-2022-11-24' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (24 commits)
  test_kprobes: fix implicit declaration error of test_kprobes
  nilfs2: fix nilfs_sufile_mark_dirty() not set segment usage as dirty
  mm/cgroup/reclaim: fix dirty pages throttling on cgroup v1
  mm: fix unexpected changes to {failslab|fail_page_alloc}.attr
  swapfile: fix soft lockup in scan_swap_map_slots
  hugetlb: fix __prep_compound_gigantic_page page flag setting
  kfence: fix stack trace pruning
  proc/meminfo: fix spacing in SecPageTables
  mm: multi-gen LRU: retry folios written back while isolated
  mailmap: update email address for Satya Priya
  mm/migrate_device: return number of migrating pages in args->cpages
  kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible
  MAINTAINERS: update Alex Hung's email address
  mailmap: update Alex Hung's email address
  mm: mmap: fix documentation for vma_mas_szero
  mm/damon/sysfs-schemes: skip stats update if the scheme directory is removed
  mm/memory: return vm_fault_t result from migrate_to_ram() callback
  mm: correctly charge compressed memory to its memcg
  ipc/shm: call underlying open/close vm_ops
  gcov: clang: fix the buffer overflow issue
  ...
2022-11-25 10:18:25 -08:00
Aneesh Kumar K.V
81a70c21d9 mm/cgroup/reclaim: fix dirty pages throttling on cgroup v1
balance_dirty_pages doesn't do the required dirty throttling on cgroupv1. 
See commit 9badce000e ("cgroup, writeback: don't enable cgroup writeback
on traditional hierarchies").  Instead, the kernel depends on writeback
throttling in shrink_folio_list to achieve the same goal.  With large
memory systems, the flusher may not be able to writeback quickly enough
such that we will start finding pages in the shrink_folio_list already in
writeback.  Hence for cgroupv1 let's do a reclaim throttle after waking up
the flusher.

The below test which used to fail on a 256GB system completes till the the
file system is full with this change.

root@lp2:/sys/fs/cgroup/memory# mkdir test
root@lp2:/sys/fs/cgroup/memory# cd test/
root@lp2:/sys/fs/cgroup/memory/test# echo 120M > memory.limit_in_bytes
root@lp2:/sys/fs/cgroup/memory/test# echo $$ > tasks
root@lp2:/sys/fs/cgroup/memory/test# dd if=/dev/zero of=/home/kvaneesh/test bs=1M
Killed

Link: https://lkml.kernel.org/r/20221118070603.84081-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: zefan li <lizefan.x@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:45 -08:00
Qi Zheng
ea4452de2a mm: fix unexpected changes to {failslab|fail_page_alloc}.attr
When we specify __GFP_NOWARN, we only expect that no warnings will be
issued for current caller.  But in the __should_failslab() and
__should_fail_alloc_page(), the local GFP flags alter the global
{failslab|fail_page_alloc}.attr, which is persistent and shared by all
tasks.  This is not what we expected, let's fix it.

[akpm@linux-foundation.org: unexport should_fail_ex()]
Link: https://lkml.kernel.org/r/20221118100011.2634-1-zhengqi.arch@bytedance.com
Fixes: 3f913fc5f9 ("mm: fix missing handler for __GFP_NOWARN")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:44 -08:00
Chen Wandun
de1ccfb648 swapfile: fix soft lockup in scan_swap_map_slots
A softlockup occurs in scan free swap slot under huge memory pressure. 
The test scenario is: 64 CPU cores, 64GB memory, and 28 zram devices, the
disksize of each zram device is 50MB.

LATENCY_LIMIT is used to prevent softlockups in scan_swap_map_slots(), but
the real loop number would more than LATENCY_LIMIT because of "goto checks
and goto scan" repeatly without decreasing latency limit.

In order to fix it, decrease latency_ration in advance.

There is also a suspicious place that will cause softlockups in
get_swap_pages().  In this function, the "goto start_over" may result in
continuous scanning of the swap partition.  If there is no cond_sched in
scan_swap_map_slots(), it would cause a softlockup (I am not sure about
this).

WARN: soft lockup - CPU#11 stuck for 11s! [kswapd0:466]
CPU: 11 PID: 466 Comm: kswapd@ Kdump: loaded Tainted: G
dump backtrace+0x0/0x1le4
show stack+0x20/@x2c
dump_stack+0xd8/0x140
watchdog print_info+0x48/0x54
watchdog_process_before_softlockup+0x98/0xa0
watchdog_timer_fn+0xlac/0x2d0
hrtimer_rum_queues+0xb0/0x130
hrtimer_interrupt+0x13c/0x3c0
arch_timer_handler_virt+0x3c/0x50
handLe_percpu_devid_irq+0x90/0x1f4
handle domain irq+0x84/0x100
gic_handle_irq+0x88/0x2b0
e11 ira+0xhB/Bx140
scan_swap_map_slots+0x678/0x890
get_swap_pages+0x29c/0x440
get_swap_page+0x120/0x2e0
add_to_swap+UX2U/0XyC
shrink_page_list+0x5d0/0x152c
shrink_inactive_list+0xl6c/Bx500
shrink_lruvec+0x270/0x304

WARN: soft lockup - CPU#32 stuck for 11s! [stress-ng:309915]
watchdog_timer_fn+0x1ac/0x2d0
__run_hrtimer+0x98/0x2a0
__hrtimer_run_queues+0xb0/0x130
hrtimer_interrupt+0x13c/0x3c0
arch_timer_handler_virt+0x3c/0x50
handle_percpu_devid_irq+0x90/0x1f4
__handle_domain_irq+0x84/0x100
gic_handle_irq+0x88/0x2b0
el1_irq+0xb8/0x140
get_swap_pages+0x1e8/0x440
get_swap_page+0x1c8/0x2e0
add_to_swap+0x20/0x9c
shrink_page_list+0x5d0/0x152c
reclaim_pages+0x160/0x310
madvise_cold_or_pageout_pte_range+0x7bc/0xe3c
walk_pmd_range.isra.0+0xac/0x22c
walk_pud_range+0xfc/0x1c0
walk_pgd_range+0x158/0x1b0
__walk_page_range+0x64/0x100
walk_page_range+0x104/0x150

Link: https://lkml.kernel.org/r/20221118133850.3360369-1-chenwandun@huawei.com
Fixes: 048c27fd72 ("[PATCH] swap: scan_swap_map latency breaks")
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: <xialonglong1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:44 -08:00
Mike Kravetz
7fb0728a9b hugetlb: fix __prep_compound_gigantic_page page flag setting
Commit 2b21624fc2 ("hugetlb: freeze allocated pages before creating
hugetlb pages") changed the order page flags were cleared and set in the
head page.  It moved the __ClearPageReserved after __SetPageHead. 
However, there is a check to make sure __ClearPageReserved is never done
on a head page.  If CONFIG_DEBUG_VM_PGFLAGS is enabled, the following BUG
will be hit when creating a hugetlb gigantic page:

    page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page))
    ------------[ cut here ]------------
    kernel BUG at include/linux/page-flags.h:500!
    Call Trace will differ depending on whether hugetlb page is created
    at boot time or run time.

Make sure to __ClearPageReserved BEFORE __SetPageHead.

Link: https://lkml.kernel.org/r/20221118195249.178319-1-mike.kravetz@oracle.com
Fixes: 2b21624fc2 ("hugetlb: freeze allocated pages before creating hugetlb pages")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Tested-by: Tarun Sahu <tsahu@linux.ibm.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:44 -08:00
Marco Elver
747c0f35f2 kfence: fix stack trace pruning
Commit b140513524 ("mm/sl[au]b: generalize kmalloc subsystem")
refactored large parts of the kmalloc subsystem, resulting in the stack
trace pruning logic done by KFENCE to no longer work.

While b140513524 attempted to fix the situation by including
'__kmem_cache_free' in the list of functions KFENCE should skip through,
this only works when the compiler actually optimized the tail call from
kfree() to __kmem_cache_free() into a jump (and thus kfree() _not_
appearing in the full stack trace to begin with).

In some configurations, the compiler no longer optimizes the tail call
into a jump, and __kmem_cache_free() appears in the stack trace.  This
means that the pruned stack trace shown by KFENCE would include kfree()
which is not intended - for example:

 | BUG: KFENCE: invalid free in kfree+0x7c/0x120
 |
 | Invalid free of 0xffff8883ed8fefe0 (in kfence-#126):
 |  kfree+0x7c/0x120
 |  test_double_free+0x116/0x1a9
 |  kunit_try_run_case+0x90/0xd0
 | [...]

Fix it by moving __kmem_cache_free() to the list of functions that may be
tail called by an allocator entry function, making the pruning logic work
in both the optimized and unoptimized tail call cases.

Link: https://lkml.kernel.org/r/20221118152216.3914899-1-elver@google.com
Fixes: b140513524 ("mm/sl[au]b: generalize kmalloc subsystem")
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:44 -08:00
Yu Zhao
359a5e1416 mm: multi-gen LRU: retry folios written back while isolated
The page reclaim isolates a batch of folios from the tail of one of the
LRU lists and works on those folios one by one.  For a suitable
swap-backed folio, if the swap device is async, it queues that folio for
writeback.  After the page reclaim finishes an entire batch, it puts back
the folios it queued for writeback to the head of the original LRU list.

In the meantime, the page writeback flushes the queued folios also by
batches.  Its batching logic is independent from that of the page reclaim.
For each of the folios it writes back, the page writeback calls
folio_rotate_reclaimable() which tries to rotate a folio to the tail.

folio_rotate_reclaimable() only works for a folio after the page reclaim
has put it back.  If an async swap device is fast enough, the page
writeback can finish with that folio while the page reclaim is still
working on the rest of the batch containing it.  In this case, that folio
will remain at the head and the page reclaim will not retry it before
reaching there.

This patch adds a retry to evict_folios().  After evict_folios() has
finished an entire batch and before it puts back folios it cannot free
immediately, it retries those that may have missed the rotation.

Before this patch, ~60% of folios swapped to an Intel Optane missed
folio_rotate_reclaimable().  After this patch, ~99% of missed folios were
reclaimed upon retry.

This problem affects relatively slow async swap devices like Samsung 980
Pro much less and does not affect sync swap devices like zram or zswap at
all.

Link: https://lkml.kernel.org/r/20221116013808.3995280-1-yuzhao@google.com
Fixes: ac35a49023 ("mm: multi-gen LRU: minimal implementation")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: "Yin, Fengwei" <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:43 -08:00
Alistair Popple
44af0b45d5 mm/migrate_device: return number of migrating pages in args->cpages
migrate_vma->cpages originally contained a count of the number of pages
migrating including non-present pages which can be populated directly on
the target.

Commit 241f688596 ("mm/migrate_device.c: refactor migrate_vma and
migrate_device_coherent_page()") inadvertantly changed this to contain
just the number of pages that were unmapped.  Usage of migrate_vma->cpages
isn't documented, but most drivers use it to see if all the requested
addresses can be migrated so restore the original behaviour.

Link: https://lkml.kernel.org/r/20221111005135.1344004-1-apopple@nvidia.com
Fixes: 241f688596 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reported-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:43 -08:00
Ian Cowan
4a42344081 mm: mmap: fix documentation for vma_mas_szero
When the struct_mm input, mm, was changed to a struct ma_state, mas, the
documentation for the function was never updated.  This updates that
documentation reference.

Link: https://lkml.kernel.org/r/20221114003349.41235-1-ian@linux.cowan.aero
Signed-off-by: Ian Cowan <ian@linux.cowan.aero>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:42 -08:00
SeongJae Park
8468b48661 mm/damon/sysfs-schemes: skip stats update if the scheme directory is removed
A DAMON sysfs interface user can start DAMON with a scheme, remove the
sysfs directory for the scheme, and then ask update of the scheme's stats.
Because the schemes stats update logic isn't aware of the situation, it
results in an invalid memory access.  Fix the bug by checking if the
scheme sysfs directory exists.

Link: https://lkml.kernel.org/r/20221114175552.1951-1-sj@kernel.org
Fixes: 0ac32b8aff ("mm/damon/sysfs: support DAMOS stats")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[v5.18]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:42 -08:00
Alistair Popple
4a955bed88 mm/memory: return vm_fault_t result from migrate_to_ram() callback
The migrate_to_ram() callback should always succeed, but in rare cases can
fail usually returning VM_FAULT_SIGBUS.  Commit 16ce101db8
("mm/memory.c: fix race when faulting a device private page") incorrectly
stopped passing the return code up the stack.  Fix this by setting the ret
variable, restoring the previous behaviour on migrate_to_ram() failure.

Link: https://lkml.kernel.org/r/20221114115537.727371-1-apopple@nvidia.com
Fixes: 16ce101db8 ("mm/memory.c: fix race when faulting a device private page")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:42 -08:00
Li Liguang
cd08d80ecd mm: correctly charge compressed memory to its memcg
Kswapd will reclaim memory when memory pressure is high, the annonymous
memory will be compressed and stored in the zpool if zswap is enabled. 
The memcg_kmem_bypass() in get_obj_cgroup_from_page() will bypass the
kernel thread and cause the compressed memory not be charged to its memory
cgroup.

Remove the memcg_kmem_bypass() call and properly charge compressed memory
to its corresponding memory cgroup.

Link: https://lore.kernel.org/linux-mm/CALvZod4nnn8BHYqAM4xtcR0Ddo2-Wr8uKm9h_CHWUaXw7g_DCg@mail.gmail.com/
Link: https://lkml.kernel.org/r/20221114194828.100822-1-hannes@cmpxchg.org
Fixes: f4840ccfca ("zswap: memcg accounting")
Signed-off-by: Li Liguang <liliguang@baidu.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>	[5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:42 -08:00
Gautam Menghani
045634ff1e mm/khugepaged: refactor mm_khugepaged_scan_file tracepoint to remove filename from function call
Refactor the mm_khugepaged_scan_file tracepoint to move filename
dereference to the tracepoint definition, to maintain consistency with
other tracepoints[1].

[1]:lore.kernel.org/lkml/20221024111621.3ba17e2c@gandalf.local.home/

Link: https://lkml.kernel.org/r/20221026044524.54793-1-gautammenghani201@gmail.com
Fixes: d41fd2016e ("mm/khugepaged: add tracepoint to hpage_collapse_scan_file()")
Signed-off-by: Gautam Menghani <gautammenghani201@gmail.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:41 -08:00
Charan Teja Kalla
ed86b74874 mm/page_exit: fix kernel doc warning in page_ext_put()
Fix the below compiler warnings reported with 'make W=1 mm/'. 
mm/page_ext.c:178: warning: Function parameter or member 'page_ext' not
described in 'page_ext_put'.

[quic_pkondeti@quicinc.com: better patch title]
Link: https://lkml.kernel.org/r/1667884582-2465-1-git-send-email-quic_charante@quicinc.com
Fixes: b1d5488a25 ("mm: fix use-after free of page_ext after race with memory-offline")
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavan Kondeti <quic_pkondeti@quicinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:41 -08:00
Yang Shi
e031ff96b3 mm: khugepaged: allow page allocation fallback to eligible nodes
Syzbot reported the below splat:

WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 __alloc_pages_node include/linux/gfp.h:221 [inline]
WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 hpage_collapse_alloc_page mm/khugepaged.c:807 [inline]
WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963
Modules linked in:
CPU: 1 PID: 3646 Comm: syz-executor210 Not tainted 6.1.0-rc1-syzkaller-00454-ga70385240892 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
RIP: 0010:__alloc_pages_node include/linux/gfp.h:221 [inline]
RIP: 0010:hpage_collapse_alloc_page mm/khugepaged.c:807 [inline]
RIP: 0010:alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963
Code: e5 01 4c 89 ee e8 6e f9 ae ff 4d 85 ed 0f 84 28 fc ff ff e8 70 fc ae ff 48 8d 6b ff 4c 8d 63 07 e9 16 fc ff ff e8 5e fc ae ff <0f> 0b e9 96 fa ff ff 41 bc 1a 00 00 00 e9 86 fd ff ff e8 47 fc ae
RSP: 0018:ffffc90003fdf7d8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888077f457c0 RSI: ffffffff81cd8f42 RDI: 0000000000000001
RBP: ffff888079388c0c R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f6b48ccf700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6b48a819f0 CR3: 00000000171e7000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 collapse_file+0x1ca/0x5780 mm/khugepaged.c:1715
 hpage_collapse_scan_file+0xd6c/0x17a0 mm/khugepaged.c:2156
 madvise_collapse+0x53a/0xb40 mm/khugepaged.c:2611
 madvise_vma_behavior+0xd0a/0x1cc0 mm/madvise.c:1066
 madvise_walk_vmas+0x1c7/0x2b0 mm/madvise.c:1240
 do_madvise.part.0+0x24a/0x340 mm/madvise.c:1419
 do_madvise mm/madvise.c:1432 [inline]
 __do_sys_madvise mm/madvise.c:1432 [inline]
 __se_sys_madvise mm/madvise.c:1430 [inline]
 __x64_sys_madvise+0x113/0x150 mm/madvise.c:1430
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6b48a4eef9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6b48ccf318 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f6b48af0048 RCX: 00007f6b48a4eef9
RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000000020000000
RBP: 00007f6b48af0040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6b48aa53a4
R13: 00007f6b48bffcbf R14: 00007f6b48ccf400 R15: 0000000000022000
 </TASK>

The khugepaged code would pick up the node with the most hit as the preferred
node, and also tries to do some balance if several nodes have the same
hit record.  Basically it does conceptually:
    * If the target_node <= last_target_node, then iterate from
last_target_node + 1 to MAX_NUMNODES (1024 on default config)
    * If the max_value == node_load[nid], then target_node = nid

But there is a corner case, paritucularly for MADV_COLLAPSE, that the
non-existing node may be returned as preferred node.

Assuming the system has 2 nodes, the target_node is 0 and the
last_target_node is 1, if MADV_COLLAPSE path is hit, the max_value may
be 0, then it may return 2 for target_node, but it is actually not
existing (offline), so the warn is triggered.

The node balance was introduced by commit 9f1b868a13 ("mm: thp:
khugepaged: add policy for finding target node") to satisfy
"numactl --interleave=all".  But interleaving is a mere hint rather than
something that has hard requirements.

So use nodemask to record the nodes which have the same hit record, the
hugepage allocation could fallback to those nodes.  And remove
__GFP_THISNODE since it does disallow fallback.  And if the nodemask
just has one node set, it means there is one single node has the most
hit record, the nodemask approach actually behaves like __GFP_THISNODE.

Link: https://lkml.kernel.org/r/20221108184357.55614-2-shy828301@gmail.com
Fixes: 7d8faaf155 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse")
Signed-off-by: Yang Shi <shy828301@gmail.com>
Suggested-by: Zach O'Keefe <zokeefe@google.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reported-by: <syzbot+0044b22d177870ee974f@syzkaller.appspotmail.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:41 -08:00
Johannes Weiner
f53af4285d mm: vmscan: fix extreme overreclaim and swap floods
During proactive reclaim, we sometimes observe severe overreclaim, with
several thousand times more pages reclaimed than requested.

This trace was obtained from shrink_lruvec() during such an instance:

    prio:0 anon_cost:1141521 file_cost:7767
    nr_reclaimed:4387406 nr_to_reclaim:1047 (or_factor:4190)
    nr=[7161123 345 578 1111]

While he reclaimer requested 4M, vmscan reclaimed close to 16G, most of it
by swapping.  These requests take over a minute, during which the write()
to memory.reclaim is unkillably stuck inside the kernel.

Digging into the source, this is caused by the proportional reclaim
bailout logic.  This code tries to resolve a fundamental conflict: to
reclaim roughly what was requested, while also aging all LRUs fairly and
in accordance to their size, swappiness, refault rates etc.  The way it
attempts fairness is that once the reclaim goal has been reached, it stops
scanning the LRUs with the smaller remaining scan targets, and adjusts the
remainder of the bigger LRUs according to how much of the smaller LRUs was
scanned.  It then finishes scanning that remainder regardless of the
reclaim goal.

This works fine if priority levels are low and the LRU lists are
comparable in size.  However, in this instance, the cgroup that is
targeted by proactive reclaim has almost no files left - they've already
been squeezed out by proactive reclaim earlier - and the remaining anon
pages are hot.  Anon rotations cause the priority level to drop to 0,
which results in reclaim targeting all of anon (a lot) and all of file
(almost nothing).  By the time reclaim decides to bail, it has scanned
most or all of the file target, and therefor must also scan most or all of
the enormous anon target.  This target is thousands of times larger than
the reclaim goal, thus causing the overreclaim.

The bailout code hasn't changed in years, why is this failing now?  The
most likely explanations are two other recent changes in anon reclaim:

1. Before the series starting with commit 5df741963d ("mm: fix LRU
   balancing effect of new transparent huge pages"), the VM was
   overall relatively reluctant to swap at all, even if swap was
   configured. This means the LRU balancing code didn't come into play
   as often as it does now, and mostly in high pressure situations
   where pronounced swap activity wouldn't be as surprising.

2. For historic reasons, shrink_lruvec() loops on the scan targets of
   all LRU lists except the active anon one, meaning it would bail if
   the only remaining pages to scan were active anon - even if there
   were a lot of them.

   Before the series starting with commit ccc5dc6734 ("mm/vmscan:
   make active/inactive ratio as 1:1 for anon lru"), most anon pages
   would live on the active LRU; the inactive one would contain only a
   handful of preselected reclaim candidates. After the series, anon
   gets aged similarly to file, and the inactive list is the default
   for new anon pages as well, making it often the much bigger list.

   As a result, the VM is now more likely to actually finish large
   anon targets than before.

Change the code such that only one SWAP_CLUSTER_MAX-sized nudge toward the
larger LRU lists is made before bailing out on a met reclaim goal.

This fixes the extreme overreclaim problem.

Fairness is more subtle and harder to evaluate.  No obvious misbehavior
was observed on the test workload, in any case.  Conceptually, fairness
should primarily be a cumulative effect from regular, lower priority
scans.  Once the VM is in trouble and needs to escalate scan targets to
make forward progress, fairness needs to take a backseat.  This is also
acknowledged by the myriad exceptions in get_scan_count().  This patch
makes fairness decrease gradually, as it keeps fairness work static over
increasing priority levels with growing scan targets.  This should make
more sense - although we may have to re-visit the exact values.

Link: https://lkml.kernel.org/r/20220802162811.39216-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-22 18:50:41 -08:00
Linus Torvalds
847ccab8fd Networking fixes for 6.1-rc6, including fixes from bpf
Current release - regressions:
 
   - tls: fix memory leak in tls_enc_skb() and tls_sw_fallback_init()
 
 Previous releases - regressions:
 
   - bridge: fix memory leaks when changing VLAN protocol
 
   - dsa: make dsa_master_ioctl() see through port_hwtstamp_get() shims
 
   - dsa: don't leak tagger-owned storage on switch driver unbind
 
   - eth: mlxsw: avoid warnings when not offloaded FDB entry with IPv6 is removed
 
   - eth: stmmac: ensure tx function is not running in stmmac_xdp_release()
 
   - eth: hns3: fix return value check bug of rx copybreak
 
 Previous releases - always broken:
 
   - kcm: close race conditions on sk_receive_queue
 
   - bpf: fix alignment problem in bpf_prog_test_run_skb()
 
   - bpf: fix writing offset in case of fault in strncpy_from_kernel_nofault
 
   - eth: macvlan: use built-in RCU list checking
 
   - eth: marvell: add sleep time after enabling the loopback bit
 
   - eth: octeon_ep: fix potential memory leak in octep_device_setup()
 
 Misc:
 
   - tcp: configurable source port perturb table size
 
   - bpf: Convert BPF_DISPATCHER to use static_call() (not ftrace)
 
 Signed-off-by: Paolo Abeni <pabeni@redhat.com>
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCAAwFiEEg1AjqC77wbdLX2LbKSR5jcyPE6QFAmN2FlMSHHBhYmVuaUBy
 ZWRoYXQuY29tAAoJECkkeY3MjxOkWAwQAJcV7XEB7bEssgabFkEmC4uvS/sFlyHC
 uSwFRn5ojaB2c56T1CnNYmitg9Wr4arC6Vca28iai6BgqB6t4qLRI/WWTsZiEPhi
 mt/pjNN2u9JMyaafHFHYfXnbSDWRF7kPMpNw4l3uL0vkGyjSI7LGAOP4Qh8C1h/d
 tNVSDZnj4Laj/3JtDf7Rk6ydCqPYnNdWxFfoZ/SQkjYZKD3Ze9tml7WJykAzCTLp
 yUiPC6TvHOnWIZYbB04sVVOQD4V+95TSOgEhB6wzs/CXB7iBEY+N+oCedjP9Xrfw
 n3ea4anBoTleDnJXJI57LhdJBkyoXncfbpbYLwXljyIgosr7XVTALvOG8XUhg/DW
 FzN5DWQ54jzTsx2eXFJzjQQcDIgyxazk9EdoHdqF8byCasP+fofq1JvzyqtvNSyh
 h8Ps6jdMZrWpXuFDVApXUhP32A/+9q+dFSYHJO681m6mf4CIaUXdm4aB1dkxDAvg
 PSlk797U94RQCzJgqxhrgsq1PGQPBb+qadZrAiD3aQi26g0NWCTg7uFpCeCEK2ZF
 fLwc2XxrwLQm1q7xQVoEg4UxPIIf0mUesvOD9sLDYop0rFIw8x0v7jdYM4kyhN3o
 6FWAXKxBe3LJ9jTTsVTbZbfHYpTnS8Q2KSclBN+/dZNHwwsUPHjy17Z2Ct3o3Jlm
 lNbiiD30BgsD
 =vVJk
 -----END PGP SIGNATURE-----

Merge tag 'net-6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Paolo Abeni:
 "Including fixes from bpf.

  Current release - regressions:

   - tls: fix memory leak in tls_enc_skb() and tls_sw_fallback_init()

  Previous releases - regressions:

   - bridge: fix memory leaks when changing VLAN protocol

   - dsa: make dsa_master_ioctl() see through port_hwtstamp_get() shims

   - dsa: don't leak tagger-owned storage on switch driver unbind

   - eth: mlxsw: avoid warnings when not offloaded FDB entry with IPv6
     is removed

   - eth: stmmac: ensure tx function is not running in
     stmmac_xdp_release()

   - eth: hns3: fix return value check bug of rx copybreak

  Previous releases - always broken:

   - kcm: close race conditions on sk_receive_queue

   - bpf: fix alignment problem in bpf_prog_test_run_skb()

   - bpf: fix writing offset in case of fault in
     strncpy_from_kernel_nofault

   - eth: macvlan: use built-in RCU list checking

   - eth: marvell: add sleep time after enabling the loopback bit

   - eth: octeon_ep: fix potential memory leak in octep_device_setup()

  Misc:

   - tcp: configurable source port perturb table size

   - bpf: Convert BPF_DISPATCHER to use static_call() (not ftrace)"

* tag 'net-6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (51 commits)
  net: use struct_group to copy ip/ipv6 header addresses
  net: usb: smsc95xx: fix external PHY reset
  net: usb: qmi_wwan: add Telit 0x103a composition
  netdevsim: Fix memory leak of nsim_dev->fa_cookie
  tcp: configurable source port perturb table size
  l2tp: Serialize access to sk_user_data with sk_callback_lock
  net: thunderbolt: Fix error handling in tbnet_init()
  net: microchip: sparx5: Fix potential null-ptr-deref in sparx_stats_init() and sparx5_start()
  net: lan966x: Fix potential null-ptr-deref in lan966x_stats_init()
  net: dsa: don't leak tagger-owned storage on switch driver unbind
  net/x25: Fix skb leak in x25_lapb_receive_frame()
  net: ag71xx: call phylink_disconnect_phy if ag71xx_hw_enable() fail in ag71xx_open()
  bridge: switchdev: Fix memory leaks when changing VLAN protocol
  net: hns3: fix setting incorrect phy link ksettings for firmware in resetting process
  net: hns3: fix return value check bug of rx copybreak
  net: hns3: fix incorrect hw rss hash type of rx packet
  net: phy: marvell: add sleep time after enabling the loopback bit
  net: ena: Fix error handling in ena_init()
  kcm: close race conditions on sk_receive_queue
  net: ionic: Fix error handling in ionic_init_module()
  ...
2022-11-17 08:58:36 -08:00
Jakub Kicinski
c1754bf019 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Andrii Nakryiko says:

====================
bpf 2022-11-11

We've added 11 non-merge commits during the last 8 day(s) which contain
a total of 11 files changed, 83 insertions(+), 74 deletions(-).

The main changes are:

1) Fix strncpy_from_kernel_nofault() to prevent out-of-bounds writes,
   from Alban Crequy.

2) Fix for bpf_prog_test_run_skb() to prevent wrong alignment,
   from Baisong Zhong.

3) Switch BPF_DISPATCHER to static_call() instead of ftrace infra, with
   a small build fix on top, from Peter Zijlstra and Nathan Chancellor.

4) Fix memory leak in BPF verifier in some error cases, from Wang Yufen.

5) 32-bit compilation error fixes for BPF selftests, from Pu Lehui and
   Yang Jihong.

6) Ensure even distribution of per-CPU free list elements, from Xu Kuohai.

7) Fix copy_map_value() to track special zeroed out areas properly,
   from Xu Kuohai.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Fix offset calculation error in __copy_map_value and zero_map_value
  bpf: Initialize same number of free nodes for each pcpu_freelist
  selftests: bpf: Add a test when bpf_probe_read_kernel_str() returns EFAULT
  maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault()
  selftests/bpf: Fix test_progs compilation failure in 32-bit arch
  selftests/bpf: Fix casting error when cross-compiling test_verifier for 32-bit platforms
  bpf: Fix memory leaks in __check_func_call
  bpf: Add explicit cast to 'void *' for __BPF_DISPATCHER_UPDATE()
  bpf: Convert BPF_DISPATCHER to use static_call() (not ftrace)
  bpf: Revert ("Fix dispatcher patchable function entry to 5 bytes nop")
  bpf, test_run: Fix alignment problem in bpf_prog_test_run_skb()
====================

Link: https://lore.kernel.org/r/20221111231624.938829-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-11 18:27:40 -08:00
Linus Torvalds
d7c2b1f64e 22 hotfixes. 8 are cc:stable and the remainder address issues which were
introduced post-6.0 or which aren't considered serious enough to justify a
 -stable backport.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY27xPAAKCRDdBJ7gKXxA
 juFXAP4tSmfNDrT6khFhV0l4cS43bluErVNLh32RfXBqse8GYgEA5EPvZkOssLqY
 86ejRXFgAArxYC4caiNURUQL+IASvQo=
 =YVOx
 -----END PGP SIGNATURE-----

Merge tag 'mm-hotfixes-stable-2022-11-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "22 hotfixes.

  Eight are cc:stable and the remainder address issues which were
  introduced post-6.0 or which aren't considered serious enough to
  justify a -stable backport"

* tag 'mm-hotfixes-stable-2022-11-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
  docs: kmsan: fix formatting of "Example report"
  mm/damon/dbgfs: check if rm_contexts input is for a real context
  maple_tree: don't set a new maximum on the node when not reusing nodes
  maple_tree: fix depth tracking in maple_state
  arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging
  fs: fix leaked psi pressure state
  nilfs2: fix use-after-free bug of ns_writer on remount
  x86/traps: avoid KMSAN bugs originating from handle_bug()
  kmsan: make sure PREEMPT_RT is off
  Kconfig.debug: ensure early check for KMSAN in CONFIG_KMSAN_WARN
  x86/uaccess: instrument copy_from_user_nmi()
  kmsan: core: kmsan_in_runtime() should return true in NMI context
  mm: hugetlb_vmemmap: include missing linux/moduleparam.h
  mm/shmem: use page_mapping() to detect page cache for uffd continue
  mm/memremap.c: map FS_DAX device memory as decrypted
  Partly revert "mm/thp: carry over dirty bit when thp splits on pmd"
  nilfs2: fix deadlock in nilfs_count_free_blocks()
  mm/mmap: fix memory leak in mmap_region()
  hugetlbfs: don't delete error page from pagecache
  maple_tree: reorganize testing to restore module testing
  ...
2022-11-11 17:18:42 -08:00
Alban Crequy
8678ea0685 maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault()
If a page fault occurs while copying the first byte, this function resets one
byte before dst.
As a consequence, an address could be modified and leaded to kernel crashes if
case the modified address was accessed later.

Fixes: b58294ead1 ("maccess: allow architectures to provide kernel probing directly")
Signed-off-by: Alban Crequy <albancrequy@linux.microsoft.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Francis Laniel <flaniel@linux.microsoft.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org> [5.8]
Link: https://lore.kernel.org/bpf/20221110085614.111213-2-albancrequy@linux.microsoft.com
2022-11-11 11:44:46 -08:00
Linus Torvalds
f67dd6ce07 slab fixes for 6.1-rc4
-----BEGIN PGP SIGNATURE-----
 
 iQEzBAABCAAdFiEEjUuTAak14xi+SF7M4CHKc/GJqRAFAmNrulwACgkQ4CHKc/GJ
 qRDGWwf/bqkCffS+Eg8p3wrGEbhWb1pOWnshcPl9EttSlclIfwaby5+kHTjeKpGR
 r3nt2cRAtWH3gUbU32352TJJ97oobasFHk3aE7xorHYTQ5HVAycwiHi+6BqcEcNH
 MyH7rcOAnKV1GeE1NnX99CeOtCA0wOaO/kCAn9y1QvSifoxKaiixBodoov4CHuSt
 PPXcJU3Rgyo8pDzFya3BAScayTTNkr1MU18iacJwndhAyjWolL4tlVqoLgVsi/TA
 wHb80Moj0iPyEioxHW7OHLkoapCYr4mfB3AUUY2t91ZciFQEKfihmki2KJw2VOg5
 XBU1iNezxMJhteNJc6JqXr90nsriAw==
 =p9yC
 -----END PGP SIGNATURE-----

Merge tag 'slab-for-6.1-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab fixes from Vlastimil Babka:
 "Most are small fixups as described below.

  The !CONFIG_TRACING fix is a bit bigger and would normally be done in
  the next merge window as part of upcoming hardening changes. But we
  realized it can make the kmalloc waste tracking introduced in this
  window inaccurate, so decided to go with it now.

  Summary:

   - Remove !CONFIG_TRACING kmalloc() wrappers intended to save a
     function call, due to incompatilibity with recently introduced
     wasted space tracking and planned hardening changes.

   - A tracing parameter regression fix, by Kees Cook.

   - Two kernel-doc warning fixups, by Lukas Bulwahn and myself

* tag 'slab-for-6.1-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  mm, slab: remove duplicate kernel-doc comment for ksize()
  mm/slab_common: Restore passing "caller" for tracing
  mm/slab: remove !CONFIG_TRACING variants of kmalloc_[node_]trace()
  mm/slab_common: repair kernel-doc for __ksize()
2022-11-09 13:07:50 -08:00
SeongJae Park
1de09a7281 mm/damon/dbgfs: check if rm_contexts input is for a real context
A user could write a name of a file under 'damon/' debugfs directory,
which is not a user-created context, to 'rm_contexts' file.  In the case,
'dbgfs_rm_context()' just assumes it's the valid DAMON context directory
only if a file of the name exist.  As a result, invalid memory access
could happen as below.  Fix the bug by checking if the given input is for
a directory.  This check can filter out non-context inputs because
directories under 'damon/' debugfs directory can be created via only
'mk_contexts' file.

This bug has found by syzbot[1].

[1] https://lore.kernel.org/damon/000000000000ede3ac05ec4abf8e@google.com/

Link: https://lkml.kernel.org/r/20221107165001.5717-2-sj@kernel.org
Fixes: 75c1c2b53c ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: syzbot+6087eafb76a94c4ac9eb@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>	[5.15.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-08 15:57:25 -08:00
Alexander Potapenko
cbadaf71f7 kmsan: core: kmsan_in_runtime() should return true in NMI context
Without that, every call to __msan_poison_alloca() in NMI may end up
allocating memory, which is NMI-unsafe.

Link: https://lkml.kernel.org/r/20221102110611.1085175-1-glider@google.com
Link: https://lore.kernel.org/lkml/20221025221755.3810809-1-glider@google.com/
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-08 15:57:24 -08:00
Vasily Gorbik
db5e8d8431 mm: hugetlb_vmemmap: include missing linux/moduleparam.h
The kernel test robot reported build failures with a 'randconfig' on s390:
>> mm/hugetlb_vmemmap.c:421:11: error: a function declaration without a
prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0);
             ^

Link: https://lore.kernel.org/linux-mm/202210300751.rG3UDsuc-lkp@intel.com/
Link: https://lkml.kernel.org/r/patch.git-296b83ca939b.your-ad-here.call-01667411912-ext-5073@work.hours
Fixes: 30152245c6 ("mm: hugetlb_vmemmap: replace early_param() with core_param()")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-08 15:57:23 -08:00
Peter Xu
93b0d91787 mm/shmem: use page_mapping() to detect page cache for uffd continue
mfill_atomic_install_pte() checks page->mapping to detect whether one page
is used in the page cache.  However as pointed out by Matthew, the page
can logically be a tail page rather than always the head in the case of
uffd minor mode with UFFDIO_CONTINUE.  It means we could wrongly install
one pte with shmem thp tail page assuming it's an anonymous page.

It's not that clear even for anonymous page, since normally anonymous
pages also have page->mapping being setup with the anon vma.  It's safe
here only because the only such caller to mfill_atomic_install_pte() is
always passing in a newly allocated page (mcopy_atomic_pte()), whose
page->mapping is not yet setup.  However that's not extremely obvious
either.

For either of above, use page_mapping() instead.

Link: https://lkml.kernel.org/r/Y2K+y7wnhC4vbnP2@x1n
Fixes: 153132571f ("userfaultfd/shmem: support UFFDIO_CONTINUE for shmem")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-08 15:57:23 -08:00