Re: [PATCH 4/4] cpuset: Hold callback_mutex in cpuset_clone()

[Paul Menage <menage@google.com>]

On Wed, Feb 16, 2011 at 5:50 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
> Chaning cpuset->mems/cpuset->cpus should be protected under
> callback_mutex.
>
> cpuset_clone() doesn't follow this rule. It's ok because it's
> called when creating and initializing a cgroup, but we'd better
> hold the lock to avoid subtil break in the future.
>
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

Acked-by: Paul Menage <menage@google.com>

Patch title should be s/cpuset_clone/cpuset_post_clone/

> ---
>  kernel/cpuset.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 1e18d26..445573b 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -1840,8 +1840,10 @@ static void cpuset_post_clone(struct cgroup_subsys *ss,
>        cs = cgroup_cs(cgroup);
>        parent_cs = cgroup_cs(parent);
>
> +       mutex_lock(&callback_mutex);
>        cs->mems_allowed = parent_cs->mems_allowed;
>        cpumask_copy(cs->cpus_allowed, parent_cs->cpus_allowed);
> +       mutex_unlock(&callback_mutex);
>        return;
>  }
>
> --
> 1.7.3.1
>

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