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

Michal Hocko
2018-01-30T09:51:39Z

On Tue 30-01-18 09:11:27, Florian Westphal wrote:
> Michal Hocko <mhocko@kernel.org> wrote:
> > On Mon 29-01-18 23:35:22, Florian Westphal wrote:
> > > Kirill A. Shutemov <kirill@shutemov.name> wrote:
> > [...]
> > > > I hate what I'm saying, but I guess we need some tunable here.
> > > > Not sure what exactly.
> > >
> > > Would memcg help?
> >
> > That really depends. I would have to check whether vmalloc path obeys
> > __GFP_ACCOUNT (I suspect it does except for page tables allocations but
> > that shouldn't be a big deal). But then the other potential problem is
> > the life time of the xt_table_info (or other potentially large) data
> > structures. Are they bound to any process life time.
>
> No.
>
> > Because if they are
> > not then the OOM killer will not help. The OOM panic earlier in this
> > thread suggests it doesn't because the test case managed to eat all the
> > available memory and killed all the eligible tasks which didn't help.
>
> Yes, which is why we do not want any OOM killer invocation in first
> place...

The problem is that as soon as you eat that memory and ask for more
until you fail with ENOMEM then the OOM is simply unavoidable.
--
Michal Hocko
SUSE Labs