On 2018/10/22 17:48, Michal Hocko wrote: > On Mon 22-10-18 16:58:50, Tetsuo Handa wrote: >> Michal Hocko wrote: >>> --- a/mm/oom_kill.c >>> +++ b/mm/oom_kill.c >>> @@ -898,6 +898,7 @@ static void __oom_kill_process(struct task_struct >>> *victim) >>> if (unlikely(p->flags & PF_KTHREAD)) >>> continue; >>> do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, PIDTYPE_TGID); >>> + mark_oom_victim(p); >>> } >>> rcu_read_unlock(); >>> >>> -- >> >> Wrong. Either > > You are right. The mm might go away between process_shares_mm and here. > While your find_lock_task_mm would be correct I believe we can do better > by using the existing mm that we already have. I will make it a separate > patch to clarity.
Still wrong. p->mm == NULL means that we are too late to set TIF_MEMDIE on that thread. Passing non-NULL mm to mark_oom_victim() won't help. > @@ -898,7 +897,7 @@ static void __oom_kill_process(struct task_struct *victim) > if (unlikely(p->flags & PF_KTHREAD)) > continue; > do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, PIDTYPE_TGID); > - mark_oom_victim(p); > + mark_oom_victim(p, mm); > } > rcu_read_unlock(); >
