Michal Hocko wrote: > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 5bb2f7698ad7..0e33e912f7e4 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -820,6 +820,13 @@ void oom_kill_process(struct oom_control *oc, struct > task_struct *p, > task_unlock(victim); > > /* > + * skip expensive iterations over all tasks if we know that there > + * are no users outside of threads in the same thread group > + */ > + if (atomic_read(&mm->mm_users) <= get_nr_threads(victim)) > + goto oom_reap;
Is this really safe? Isn't it possible that victim thread's thread group has more than atomic_read(&mm->mm_users) threads which are past exit_mm() and blocked at exit_task_work() which are before __exit_signal() from release_task() from exit_notify()? > + > + /* > * Kill all user processes sharing victim->mm in other thread groups, if > * any. They don't get access to memory reserves, though, to avoid > * depletion of all memory. This prevents mm->mmap_sem livelock when an
