Messages in this thread | | | Date | Tue, 18 Jun 2013 09:05:07 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH 1/3] cgroup: fix umount vs cgroup_cfs_commit() race |
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On Tue, Jun 18, 2013 at 06:40:19PM +0800, Li Zefan wrote: > cgroup_cfs_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>
Applied 1-3 to cgroup/for-3.11 w/ stable cc'd on 1 and 2.
Thanks!
-- tejun
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