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| author | Li Zefan <lizefan@huawei.com> | 2014-09-04 14:43:38 +0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-09-05 01:36:19 +0900 |
| commit | aa32362f011c6e863132b16c1761487166a4bad2 (patch) | |
| tree | 21274b6b6111e83af93568c4e7c10357f4e58a0f /kernel/debug | |
| parent | a4189487da1b4f8260c6006b9dc47c3c4107a5ae (diff) | |
| download | blackbird-op-linux-aa32362f011c6e863132b16c1761487166a4bad2.tar.gz blackbird-op-linux-aa32362f011c6e863132b16c1761487166a4bad2.zip | |
cgroup: check cgroup liveliness before unbreaking kernfs
When cgroup_kn_lock_live() is called through some kernfs operation and
another thread is calling cgroup_rmdir(), we'll trigger the warning in
cgroup_get().
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1228 at kernel/cgroup.c:1034 cgroup_get+0x89/0xa0()
...
Call Trace:
[<c16ee73d>] dump_stack+0x41/0x52
[<c10468ef>] warn_slowpath_common+0x7f/0xa0
[<c104692d>] warn_slowpath_null+0x1d/0x20
[<c10bb999>] cgroup_get+0x89/0xa0
[<c10bbe58>] cgroup_kn_lock_live+0x28/0x70
[<c10be3c1>] __cgroup_procs_write.isra.26+0x51/0x230
[<c10be5b2>] cgroup_tasks_write+0x12/0x20
[<c10bb7b0>] cgroup_file_write+0x40/0x130
[<c11aee71>] kernfs_fop_write+0xd1/0x160
[<c1148e58>] vfs_write+0x98/0x1e0
[<c114934d>] SyS_write+0x4d/0xa0
[<c16f656b>] sysenter_do_call+0x12/0x12
---[ end trace 6f2e0c38c2108a74 ]---
Fix this by calling css_tryget() instead of cgroup_get().
v2:
- move cgroup_tryget() right below cgroup_get() definition. (Tejun)
Cc: <stable@vger.kernel.org> # 3.15+
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/debug')
0 files changed, 0 insertions, 0 deletions
