9adcc852d5
[ Upstream commit 027690c75e8fd91b60a634d31c4891a6e39d45bd ]
I made every global per-network-namespace instead. But perhaps doing
that to this slab was a step too far.
The kmem_cache_create call in our net init method also seems to be
responsible for this lockdep warning:
[ 45.163710] Unable to find swap-space signature
[ 45.375718] trinity-c1 (855): attempted to duplicate a private mapping with mremap. This is not supported.
[ 46.055744] futex_wake_op: trinity-c1 tries to shift op by -209; fix this program
[ 51.011723]
[ 51.013378] ======================================================
[ 51.013875] WARNING: possible circular locking dependency detected
[ 51.014378] 5.2.0-rc2 #1 Not tainted
[ 51.014672] ------------------------------------------------------
[ 51.015182] trinity-c2/886 is trying to acquire lock:
[ 51.015593] 000000005405f099 (slab_mutex){+.+.}, at: slab_attr_store+0xa2/0x130
[ 51.016190]
[ 51.016190] but task is already holding lock:
[ 51.016652] 00000000ac662005 (kn->count#43){++++}, at: kernfs_fop_write+0x286/0x500
[ 51.017266]
[ 51.017266] which lock already depends on the new lock.
[ 51.017266]
[ 51.017909]
[ 51.017909] the existing dependency chain (in reverse order) is:
[ 51.018497]
[ 51.018497] -> #1 (kn->count#43){++++}:
[ 51.018956] __lock_acquire+0x7cf/0x1a20
[ 51.019317] lock_acquire+0x17d/0x390
[ 51.019658] __kernfs_remove+0x892/0xae0
[ 51.020020] kernfs_remove_by_name_ns+0x78/0x110
[ 51.020435] sysfs_remove_link+0x55/0xb0
[ 51.020832] sysfs_slab_add+0xc1/0x3e0
[ 51.021332] __kmem_cache_create+0x155/0x200
[ 51.021720] create_cache+0xf5/0x320
[ 51.022054] kmem_cache_create_usercopy+0x179/0x320
[ 51.022486] kmem_cache_create+0x1a/0x30
[ 51.022867] nfsd_reply_cache_init+0x278/0x560
[ 51.023266] nfsd_init_net+0x20f/0x5e0
[ 51.023623] ops_init+0xcb/0x4b0
[ 51.023928] setup_net+0x2fe/0x670
[ 51.024315] copy_net_ns+0x30a/0x3f0
[ 51.024653] create_new_namespaces+0x3c5/0x820
[ 51.025257] unshare_nsproxy_namespaces+0xd1/0x240
[ 51.025881] ksys_unshare+0x506/0x9c0
[ 51.026381] __x64_sys_unshare+0x3a/0x50
[ 51.026937] do_syscall_64+0x110/0x10b0
[ 51.027509] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 51.028175]
[ 51.028175] -> #0 (slab_mutex){+.+.}:
[ 51.028817] validate_chain+0x1c51/0x2cc0
[ 51.029422] __lock_acquire+0x7cf/0x1a20
[ 51.029947] lock_acquire+0x17d/0x390
[ 51.030438] __mutex_lock+0x100/0xfa0
[ 51.030995] mutex_lock_nested+0x27/0x30
[ 51.031516] slab_attr_store+0xa2/0x130
[ 51.032020] sysfs_kf_write+0x11d/0x180
[ 51.032529] kernfs_fop_write+0x32a/0x500
[ 51.033056] do_loop_readv_writev+0x21d/0x310
[ 51.033627] do_iter_write+0x2e5/0x380
[ 51.034148] vfs_writev+0x170/0x310
[ 51.034616] do_pwritev+0x13e/0x160
[ 51.035100] __x64_sys_pwritev+0xa3/0x110
[ 51.035633] do_syscall_64+0x110/0x10b0
[ 51.036200] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 51.036924]
[ 51.036924] other info that might help us debug this:
[ 51.036924]
[ 51.037876] Possible unsafe locking scenario:
[ 51.037876]
[ 51.038556] CPU0 CPU1
[ 51.039130] ---- ----
[ 51.039676] lock(kn->count#43);
[ 51.040084] lock(slab_mutex);
[ 51.040597] lock(kn->count#43);
[ 51.041062] lock(slab_mutex);
[ 51.041320]
[ 51.041320] *** DEADLOCK ***
[ 51.041320]
[ 51.041793] 3 locks held by trinity-c2/886:
[ 51.042128] #0: 000000001f55e152 (sb_writers#5){.+.+}, at: vfs_writev+0x2b9/0x310
[ 51.042739] #1: 00000000c7d6c034 (&of->mutex){+.+.}, at: kernfs_fop_write+0x25b/0x500
[ 51.043400] #2: 00000000ac662005 (kn->count#43){++++}, at: kernfs_fop_write+0x286/0x500
Reported-by: kernel test robot <lkp@intel.com>
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.