Re: [PATCH] cgroup: fix unbalanced locking

Cong Wang
2014-09-18T16:14:37Z

On Thu, Sep 18, 2014 at 2:28 AM, Zefan Li <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> wrote:
> cgroup_pidlist_start() holds cgrp->pidlist_mutex and then calls
> pidlist_array_load(), and cgroup_pidlist_stop() releases the mutex.
>
> It is wrong that we release the mutex in the failure path in
> pidlist_array_load(), because cgroup_pidlist_stop() will be called
> no matter if cgroup_pidlist_start() returns errno or not.
>

I found same thing yesterday and tried to analysis if this could
be the cause of the the NULL ptr def bug I saw, it seems not.

Anyway, this fix is definitely correct,

Acked-by: Cong Wang <xiyou.wangcong-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>