On Thu 07-11-19 22:41:13, Roman Gushchin wrote: > On Thu, Nov 07, 2019 at 06:02:00PM +0100, Michal Hocko wrote: > > On Thu 07-11-19 16:42:41, Roman Gushchin wrote: [...] > > > It's an exiting task with the PF_EXITING flag set and it's in their late stages > > > of life. > > > > This is a signal delivery path AFAIU (get_signal) and the coredumping > > happens before do_exit. My understanding is that that unlinking > > happens from cgroup_exit. So either I am misreading the backtrace or > > there is some other way to leave cgroups or there is something more > > going on. > > Yeah, you're right. I have no better explanation for this and the similar, > mentioned in the commit bsd accounting issue, Tejun mentioned bsd accounting issue as well, but I do not see any explicit reference to it in neither of the two patches. > than some very rare race condition > that allows cgroups to be offlined with a task inside. > > I'll think more about it. Thanks a lot. As I've said, I am not opposing this change once we have a proper changelog but I find the explanation really weak. If there is a race then it should be fixed as well. Thanks! -- Michal Hocko SUSE Labs
