Files
linux/kernel
Li Zefan a09a1b8700 cgroup: fix umount vs cgroup_cfts_commit() race
commit 084457f284 upstream.

cgroup_cfts_commit() uses dget() to keep cgroup alive after cgroup_mutex
is dropped, but dget() won't prevent cgroupfs from being umounted. When
the race happens, vfs will see some dentries with non-zero refcnt while
umount is in process.

Keep running this:
  mount -t cgroup -o blkio xxx /cgroup
  umount /cgroup

And this:
  modprobe cfq-iosched
  rmmod cfs-iosched

After a while, the BUG() in shrink_dcache_for_umount_subtree() may
be triggered:

  BUG: Dentry xxx{i=0,n=blkio.yyy} still in use (1) [umount of cgroup cgroup]

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-08-11 18:35:24 -07:00
..
2013-04-22 07:09:06 -07:00
2013-04-15 13:25:16 +02:00
2012-12-20 17:40:19 -08:00
2013-05-05 00:16:35 -04:00
2013-04-30 17:04:03 -07:00