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

From: Michal Hocko
Date: Tue Jul 12 2016 - 03:19:34 EST


On Mon 11-07-16 11:33:19, Shayan Pooya wrote:
> >> Could you post the stack trace of the hung oom victim? Also could you
> >> post the full kernel log?
>
> With strace, when running 500 concurrent mem-hog tasks on the same
> kernel, 33 of them failed with:
>
> strace: ../sysdeps/nptl/fork.c:136: __libc_fork: Assertion
> `THREAD_GETMEM (self, tid) != ppid' failed.
>
> Which is: https://sourceware.org/bugzilla/show_bug.cgi?id=15392
> And discussed before at: https://lkml.org/lkml/2015/2/6/470 but that
> patch was not accepted.

OK, so the problem is that the oom killed task doesn't report the futex
release properly? If yes then I fail to see how that is memcg specific.
Could you try to clarify what you consider a bug again, please? I am not
really sure I understand this report.

Thanks!

--
Michal Hocko
SUSE Labs