Re: general protection fault in oom_unkillable_task

[Michal Hocko]

On Sat 15-06-19 09:11:37, Shakeel Butt wrote:
> On Sat, Jun 15, 2019 at 6:50 AM Michal Hocko <mhocko@xxxxxxxxxx> wrote:
[...]
> > diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> > index 5a58778c91d4..43eb479a5dc7 100644
> > --- a/mm/oom_kill.c
> > +++ b/mm/oom_kill.c
> > @@ -161,8 +161,8 @@ static bool oom_unkillable_task(struct task_struct *p,
> >                 return true;
> >
> >         /* When mem_cgroup_out_of_memory() and p is not member of the group */
> > -       if (memcg && !task_in_mem_cgroup(p, memcg))
> > -               return true;
> > +       if (memcg)
> > +               return false;
> 
> This will break the dump_tasks() usage of oom_unkillable_task(). We
> can change dump_tasks() to traverse processes like
> mem_cgroup_scan_tasks() for memcg OOMs.

Right you are. Doing a similar trick to the oom victim selection is
indeed better. We should really strive to not doing a global process
iteration when we can do a targeted scan. Care to send a patch?

Thanks!
-- 
Michal Hocko
SUSE Labs