On Thu, Jan 03, 2019 at 12:26:23AM +0000, David Howells wrote:
> Andrei Vagin <avagin@xxxxxxxxx> wrote:
>
> > It looks like the c6b3d5bcd67c ("cgroup: fix top cgroup refcnt leak")
> > commit was reverted by mistake.
> >
> > $ mkdir /tmp/cgroup
> > $ mkdir /tmp/cgroup2
> > $ mount -t cgroup -o none,name=test test /tmp/cgroup
> > $ mount -t cgroup -o none,name=test test /tmp/cgroup2
> > $ umount /tmp/cgroup
> > $ umount /tmp/cgroup2
> > $ cat /proc/self/cgroup | grep test
> > 12:name=test:/
> >
> > You can see the test cgroup was not freed.
> >
> > Cc: Li Zefan <lizefan@xxxxxxxxxx>
> > Fixes: aea3f2676c83 ("kernfs, sysfs, cgroup, intel_rdt: Support fs_context")
> > Signed-off-by: Andrei Vagin <avagin@xxxxxxxxx>
> > ---
> >
> > v2: clean up code and add the vfs/for-next tag
> > v3: fix a reference leak when kernfs_node_dentry fails
> > v4: call deactivate_locked_super() in a error case
> > v5: don't dereference fc->root after dput()
> >
> > kernel/cgroup/cgroup.c | 25 ++++++++++++++++++-------
> > 1 file changed, 18 insertions(+), 7 deletions(-)
>
> This patch doesn't work either.
I'm sorry, but we can't say anything about this patch now, because it
looks like recent changes in vfs-next break something else here...
>
> percpu ref (css_release) <= 0 (0) after switching to atomic
> RIP: 0010:percpu_ref_switch_to_atomic_rcu+0x90/0x1a0
>
> Btw, note that the subject says "v4" but the changelog says "v5".
It is v5.
>
> David
