On Mon 22-10-18 19:56:49, Tetsuo Handa wrote: > On 2018/10/22 19:43, Michal Hocko wrote: > > On Mon 22-10-18 18:42:30, Tetsuo Handa wrote: > >> 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. > > > > Why would it be too late? Or in other words why would this be harmful? > > > > Setting TIF_MEMDIE after exit_mm() completed is too late.
You are right and I am obviously dense today. I will go with find_lock_task_mm for now and push the "get rid of TIF_MEMDIE" up in the todo list. I hope I will get to it some day. -- Michal Hocko SUSE Labs
