diff options
| author | Li Zefan <lizefan@huawei.com> | 2014-09-04 14:43:38 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-05 13:41:00 -0700 |
| commit | 3d5cd32aec76ad53e2aefc72ee67fed7d2819019 (patch) | |
| tree | 436cde7e20a60626e89bebda1f2772fcf7006bc7 /kernel/taskstats.c | |
| parent | de8a646c2422cda2e3536f953677cf4b6b92f09e (diff) | |
cgroup: check cgroup liveliness before unbreaking kernfs
commit aa32362f011c6e863132b16c1761487166a4bad2 upstream.
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)
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/taskstats.c')
0 files changed, 0 insertions, 0 deletions