Re: [BUG] Early OOM and kernel NULL pointer dereference in 4.19.69

[Michal Hocko <mhocko@kernel.org>]

On Sun 01-09-19 22:43:05, Thomas Lindroth wrote:
> After upgrading to the 4.19 series I've started getting problems with
> early OOM.

What is the kenrel you have updated from? Would it be possible to try
the current Linus' tree?

> I run a Gentoo system and do large compiles like the chromium browser in a
> v1 memory cgroup. When I build chromium in the memory cgroup the OOM killer
> runs and kills programs outside of the cgroup. This happens even when there
> is plenty of free memory both in and outside of the cgroup.
[...]
> [ 1146.798696] emerge invoked oom-killer: gfp_mask=0x0(), nodemask=(null), order=0, oom_score_adj=0
> [ 1146.798699] emerge cpuset=
> [ 1146.798701] /
> [ 1146.798703]  mems_allowed=0
> [ 1146.798705] CPU: 4 PID: 16719 Comm: emerge Not tainted 4.19.69 #43
> [ 1146.798707] Hardware name: Gigabyte Technology Co., Ltd. Z97X-Gaming G1/Z97X-Gaming G1, BIOS F9 07/31/2015
> [ 1146.798708] Call Trace:
> [ 1146.798713]  dump_stack+0x46/0x60
> [ 1146.798718]  dump_header+0x67/0x28d
> [ 1146.798721]  oom_kill_process.cold.31+0xb/0x1f3
> [ 1146.798723]  out_of_memory+0x129/0x250
> [ 1146.798728]  pagefault_out_of_memory+0x64/0x77
> [ 1146.798732]  __do_page_fault+0x3c1/0x3d0
> [ 1146.798735]  do_page_fault+0x2c/0x123
> [ 1146.798738]  ? page_fault+0x8/0x30
> [ 1146.798740]  page_fault+0x1e/0x30

This is not a memcg oom killer and the oom killer itself is a reaction
to the allocation not making a forward progress. It smells like
something in the page fault path has return ENOMEM leading to
VM_FAULT_OOM. Seeing unexpected SLUB allocation failures would suggest
that something is not really working properly there.
-- 
Michal Hocko
SUSE Labs