Re: general protection fault in oom_unkillable_task

[Andrew Morton]

On Mon, 17 Jun 2019 06:23:07 -0700 Shakeel Butt <shakeelb@xxxxxxxxxx> wrote:

> > Here is a patch to use CSS_TASK_ITER_PROCS.
> >
> > From 415e52cf55bc4ad931e4f005421b827f0b02693d Mon Sep 17 00:00:00 2001
> > From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> > Date: Mon, 17 Jun 2019 00:09:38 +0900
> > Subject: [PATCH] mm: memcontrol: Use CSS_TASK_ITER_PROCS at mem_cgroup_scan_tasks().
> >
> > Since commit c03cd7738a83b137 ("cgroup: Include dying leaders with live
> > threads in PROCS iterations") corrected how CSS_TASK_ITER_PROCS works,
> > mem_cgroup_scan_tasks() can use CSS_TASK_ITER_PROCS in order to check
> > only one thread from each thread group.
> >
> > Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> 
> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
> 
> Why not add the reproducer in the commit message?

That would be nice.

More nice would be, as always, a descriptoin of the user-visible impact
of the patch.

As I understand it, it's just a bit of a cleanup against current
mainline but without this patch in place, Shakeel's "mm, oom: refactor
dump_tasks for memcg OOMs" will cause kernel crashes.  Correct?