On Tue, 7 Feb 2012, Anton Vorontsov wrote:

> There's a real possibility of killing kernel threads that might
> have issued use_mm(), so kthread's mm might become non-NULL.
> 
> This patch fixes the issue by checking for PF_KTHREAD (just as
> get_task_mm()).
> 
> Suggested-by: Oleg Nesterov <oleg@redhat.com>
> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

Acked-by: David Rientjes <rientjes@google.com>

Definitely needed.