Re: [patch 05/11 -mmotm] oom: fix possible oom_dump_tasks NULLpointer

From: David Rientjes
Date: Mon May 11 2009 - 17:28:27 EST


On Mon, 11 May 2009, Andrew Morton wrote:

> On Sun, 10 May 2009 15:07:16 -0700 (PDT)
> David Rientjes <rientjes@xxxxxxxxxx> wrote:
>
> > When /proc/sys/vm/oom_dump_tasks is enabled, it is possible to get a NULL
> > pointer for tasks that have detached mm's since task_lock() is not held
> > during the tasklist scan.
>
> ok. But a better changelog would have told us how the patch fixes the
> problem?
>

Sure, I suppose "Add the task_lock()." could follow it.

> This patch series is partially core MM and partially drivers/staging.
> I don't normally handle staging things, so I'd need to be cherrypicking
> from this lot. Is there any interdependency between the two things?
>

This was a source of confusion from me when I posted a smaller set earlier
that made the same changes to the staging driver, and the only reason I
sent the change here was because drivers/staging/android/lowmemorykiller.c
is in Linus' tree.

This patch series moves oomkilladj from struct task_struct to struct
mm_struct where it more appropriately belongs. The Android
lowmemorykiller uses oomkilladj, so it will fail to compile in Linus' git
if you pushed the patchset to him and the Android driver were enabled.

To prevent that breakage, they should probably either all go through one
series so nothing ever breaks or Greg takes the staging patches and then
pushes them when you push the other changes. I thought the former would
be easier for the maintainers (apparently not :).

I'd be fine with seperating the staging changes out, sending them to Greg,
and then just assuming that it'll all work out in the end.
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