Ritesh Harjani 8119853653 ext4: mballoc: Use this_cpu_read instead of this_cpu_ptr ...

Simplify reading a seq variable by directly using this_cpu_read API
instead of doing this_cpu_ptr and then dereferencing it.

This also avoid the below kernel BUG: which happens when
CONFIG_DEBUG_PREEMPT is enabled

BUG: using smp_processor_id() in preemptible [00000000] code: syz-fuzzer/6927
caller is ext4_mb_new_blocks+0xa4d/0x3b70 fs/ext4/mballoc.c:4711
CPU: 1 PID: 6927 Comm: syz-fuzzer Not tainted 5.7.0-next-20200602-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 check_preemption_disabled+0x20d/0x220 lib/smp_processor_id.c:48
 ext4_mb_new_blocks+0xa4d/0x3b70 fs/ext4/mballoc.c:4711
 ext4_ext_map_blocks+0x201b/0x33e0 fs/ext4/extents.c:4244
 ext4_map_blocks+0x4cb/0x1640 fs/ext4/inode.c:626
 ext4_getblk+0xad/0x520 fs/ext4/inode.c:833
 ext4_bread+0x7c/0x380 fs/ext4/inode.c:883
 ext4_append+0x153/0x360 fs/ext4/namei.c:67
 ext4_init_new_dir fs/ext4/namei.c:2757 [inline]
 ext4_mkdir+0x5e0/0xdf0 fs/ext4/namei.c:2802
 vfs_mkdir+0x419/0x690 fs/namei.c:3632
 do_mkdirat+0x21e/0x280 fs/namei.c:3655
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 42f56b7a4a7d ("ext4: mballoc: introduce pcpu seqcnt for freeing PA
to improve ENOSPC handling")
Suggested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reported-by: syzbot+82f324bb69744c5f6969@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/534f275016296996f54ecf65168bb3392b6f653d.1591699601.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

2020-06-11 11:03:26 -04:00

..

acl.c

ext4: handle ext4_mark_inode_dirty errors

2020-06-03 23:16:50 -04:00

acl.h

ext4: fix up remaining files with SPDX cleanups

2017-12-17 22:00:59 -05:00

balloc.c

ext4: balloc: use task_pid_nr() helper

2020-06-03 23:16:52 -04:00

bitmap.c

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

block_validity.c

ext4: save all error info in save_error_info() and drop ext4_set_errno()

2020-04-01 17:29:06 -04:00

dir.c

ext4: avoid utf8_strncasecmp() with unstable name

2020-06-11 11:01:33 -04:00

ext4_extents.h

ext4: fix EXT_MAX_EXTENT/INDEX to check for zeroed eh_max

2020-06-03 23:16:49 -04:00

ext4_jbd2.c

ext4: remove set but not used variable 'es' in ext4_jbd2.c

2020-04-15 23:58:49 -04:00

ext4_jbd2.h

ext4: drop ext4_journal_free_reserved()

2020-06-03 23:16:53 -04:00

ext4.h

Enable ext4 support for per-file/directory dax operations

2020-06-11 10:51:44 -04:00

extents_status.c

ext4: remove unnecessary comparisons to bool

2020-06-03 23:16:49 -04:00

extents_status.h

ext4: fix extent_status trace points

2020-01-25 02:03:03 -05:00

extents.c

ext4: fix partial cluster initialization when splitting extent

2020-06-11 10:57:40 -04:00

file.c

ext4: don't block for O_DIRECT if IOCB_NOWAIT is set

2020-06-03 23:16:55 -04:00

fsmap.c

ext4: fix miscellaneous sparse warnings

2019-05-12 04:49:47 -04:00

fsmap.h

ext4: fix up remaining files with SPDX cleanups

2017-12-17 22:00:59 -05:00

fsync.c

ext4: fix race between ext4_sync_parent() and rename()

2020-06-03 23:16:51 -04:00

hash.c

ext4: fix kernel oops caused by spurious casefold flag

2019-09-03 01:43:17 -04:00

ialloc.c

Enable ext4 support for per-file/directory dax operations

2020-06-11 10:51:44 -04:00

indirect.c

ext4: handle ext4_mark_inode_dirty errors

2020-06-03 23:16:50 -04:00

inline.c

ext4: handle ext4_mark_inode_dirty errors

2020-06-03 23:16:50 -04:00

inode-test.c

kunit: allow kunit tests to be loaded as a module

2020-01-09 16:42:29 -07:00

inode.c

Enable ext4 support for per-file/directory dax operations

2020-06-11 10:51:44 -04:00

ioctl.c

Enable ext4 support for per-file/directory dax operations

2020-06-11 10:51:44 -04:00

Kconfig

ext4: make ext_debug() implementation to use pr_debug()

2020-06-03 23:16:52 -04:00

Makefile

kunit: allow kunit tests to be loaded as a module

2020-01-09 16:42:29 -07:00

mballoc.c

ext4: mballoc: Use this_cpu_read instead of this_cpu_ptr

2020-06-11 11:03:26 -04:00

mballoc.h

ext4: mballoc: make mb_debug() implementation to use pr_debug()

2020-06-03 23:16:52 -04:00

migrate.c

ext4: handle ext4_mark_inode_dirty errors

2020-06-03 23:16:50 -04:00

mmp.c

ext4: save all error info in save_error_info() and drop ext4_set_errno()

2020-04-01 17:29:06 -04:00

move_extent.c

ext4: save all error info in save_error_info() and drop ext4_set_errno()

2020-04-01 17:29:06 -04:00

namei.c

ext4: handle ext4_mark_inode_dirty errors

2020-06-03 23:16:50 -04:00

page-io.c

fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t

2020-03-28 13:21:08 +01:00

readpage.c

ext4: remove unneeded check for error allocating bio_post_read_ctx

2020-01-17 16:24:54 -05:00

resize.c

ext4: fix potential race between s_flex_groups online resizing and access

2020-02-21 19:31:46 -05:00

super.c

ext4: stop overwrite the errcode in ext4_setup_super

2020-06-11 10:59:38 -04:00

symlink.c

ext4: switch to fscrypt_get_symlink()

2018-01-11 22:10:40 -05:00

sysfs.c

block: move the part_stat* helpers from genhd.h to a new header

2020-03-25 09:50:09 -06:00

truncate.h

ext4: handle layout changes to pinned DAX mappings

2018-07-29 17:00:22 -04:00

verity.c

fs/ext4: Introduce DAX inode flag

2020-05-28 22:09:47 -04:00

xattr_security.c

ext4: use XATTR_CREATE in ext4_initxattrs()

2018-05-10 11:52:14 -04:00

xattr_trusted.c

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

xattr_user.c

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

xattr.c

ext4: handle ext4_mark_inode_dirty errors

2020-06-03 23:16:50 -04:00

xattr.h

ext4: use flexible-array member for xattr structs

2020-03-14 14:43:13 -04:00