On Mon 06-08-18 19:47:00, Tetsuo Handa wrote: > On 2018/08/06 19:39, Dmitry Vyukov wrote: > > On Mon, Aug 6, 2018 at 11:48 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > >> Btw. running with the above diff on top might help us to ideantify > >> whether this is a pre-mature warning or a valid one. Still useful to > >> find out. > > Since syzbot already found a syz reproducer, you can ask syzbot to test it. > > > > > The bug report has a reproducer, so you can run it with the patch. Or > > ask syzbot to test your patch: > > https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches > > Which basically boils down to saying: > > > > #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > master > > Excuse me, but this is linux-next only problem. Therefore, If this really is a linux-next only problem then please retest with the current linux-next which has dropped the and replaced the group oom code. > #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 4603ad75c9a9..852cd3dbdcd9 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1388,6 +1388,8 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, > bool ret; > > mutex_lock(&oom_lock); > + pr_info("task=%s pid=%d invoked memcg oom killer. oom_victim=%d\n", > + current->comm, current->pid, tsk_is_oom_victim(current)); > ret = out_of_memory(&oc); > mutex_unlock(&oom_lock); > return ret; > > F.Y.I. Waiting until __mmput() completes (with timeout using OOM score feedback) > ( https://syzkaller.appspot.com/x/patch.diff?x=101e449c400000 ) solves this race. Which just means that something else is broken. Seriously, timout is not going to fix anything. It merely changes the picture. -- Michal Hocko SUSE Labs
