Re: [netfilter-core] kernel panic: Out of memory and no killable processes... (2)

Michal Hocko
2018-01-29T18:25:27Z

On Mon 29-01-18 17:57:22, Florian Westphal wrote:
> Kirill A. Shutemov <kirill@shutemov.name> wrote:
> > On Mon, Jan 29, 2018 at 08:23:57AM +0100, Florian Westphal wrote:
> > > > vmalloc() once became killable by commit 5d17a73a2ebeb8d1 ("vmalloc: back
> > > > off when the current task is killed") but then became unkillable by commit
> > > > b8c8a338f75e052d ("Revert "vmalloc: back off when the current task is
> > > > killed""). Therefore, we can't handle this problem from MM side.
> > > > Please consider adding some limit from networking side.
> > >
> > > I don't know what "some limit" would be. I would prefer if there was
> > > a way to supress OOM Killer in first place so we can just -ENOMEM user.
> >
> > Just supressing OOM kill is a bad idea. We still leave a way to allocate
> > arbitrary large buffer in kernel.
>
> Isn't that what we do everywhere in network stack?
>
> I think we should try to allocate whatever amount of memory is needed
> for the given xtables ruleset, given that is what admin requested us to do.

If this is a root only thing then __GFP_NORETRY sounds like the most
straightforward way to go.
--
Michal Hocko
SUSE Labs