Re: [PATCH -mm v2 3/3] mm/oom_kill: fix the wrong task->mm == mm checks in oom_kill_process()

From: David Rientjes
Date: Wed Sep 30 2015 - 17:16:05 EST


On Wed, 30 Sep 2015, Oleg Nesterov wrote:

> Both "child->mm == mm" and "p->mm != mm" checks in oom_kill_process()
> are wrong. task->mm can be NULL if the task is the exited group leader.
> This means in particular that "kill sharing same memory" loop can miss
> a process with a zombie leader which uses the same ->mm.
>
> Note: the process_has_mm(child, p->mm) check is still not 100% correct,
> p->mm can be NULL too. This is minor, but probably deserves a fix or a
> comment anyway.
>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
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