Re: bug in memcg oom-killer results in a hung syscall in another process in the same cgroup

From: Shayan Pooya
Date: Tue Jul 12 2016 - 18:58:23 EST


> Yep. Bug still not fixed in upstream. In our kernel I've plugged it with
> this:
>
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -2808,8 +2808,9 @@ asmlinkage __visible void schedule_tail(struct
> task_struct *prev)
> balance_callback(rq);
> preempt_enable();
>
> - if (current->set_child_tid)
> - put_user(task_pid_vnr(current), current->set_child_tid);
> + if (current->set_child_tid &&
> + put_user(task_pid_vnr(current), current->set_child_tid))
> + force_sig(SIGSEGV, current);
> }

I just verified that with your patch there is no hung processes and I
see processes getting SIGSEGV as expected.
Thanks!