Re: [PATCH] cgroup: fix a race condition in manipulating tsk->cg_list

From: Paul Menage
Date: Thu Apr 17 2008 - 01:21:00 EST


On Wed, Apr 16, 2008 at 9:59 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Task A starts exiting, passes the check for unlinking current->cg_list.
>
> So cgroup_exit() sees !list_empty(tsk->cg_list)

We don't actually set up the links running through tsk->cg_list to the
css_set objects until the first time someone calls cgroup_iter_begin()
- so anyone who never actually uses cgroups doesn't pay the list
management overhead. So in this case, the list is empty.

Paul
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