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

From: Oleg Nesterov
Date: Wed Sep 30 2015 - 09:54:10 EST

On 09/29, David Rientjes wrote:
> On Tue, 29 Sep 2015, Oleg Nesterov wrote:
> > Both "child->mm == mm" and "p->mm != mm" checks in oom_kill_process()
> > are wrong. ->mm can be if 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>
> I like this and I don't want to hold up a fix for a personal preference,
> but I find process_has_mm() to simply imply the process has a non-NULL mm.

Hmm, yes ;)

> Maybe process_shares_mm()? Something to consider.

Agreed, will rename in v2.


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