Re: [PATCH] cgroup: fix unbalanced locking

From: Cong Wang
Date: Thu Sep 18 2014 - 12:14:43 EST


On Thu, Sep 18, 2014 at 2:28 AM, Zefan Li <lizefan@xxxxxxxxxx> 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@xxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/