Re: [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core)

Michal Hocko
2016-06-24T14:05:58Z

On Thu 23-06-16 20:52:21, Oleg Nesterov wrote:
> On 06/23, Linus Torvalds wrote:
> >
> > On Thu, Jun 23, 2016 at 10:03 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> > >
> > > Let me quote my previous email ;)
> > >
> > > And we can't free/nullify it when the parent/debuger reaps a zombie,
> > > say, mark_oom_victim() expects that get_task_struct() protects
> > > thread_info as well.
> > >
> > > probably we can fix all such users though...
> >
> > TIF_MEMDIE is indeed a potential problem, but I don't think
> > mark_oom_victim() is actually problematic.
> >
> > mark_oom_victim() is called with either "current",
>
> This is no longer true in -mm tree.
>
> But I agree, this is fixable (and in fact I still hope TIF_MEMDIE will die,
> at least in its current form).

We can move the flag to the task_struct. There are still some bits left
there. This would be trivial so that the oom usage doesn't stay in the
way.
--
Michal Hocko
SUSE Labs