From: Oleg Nesterov The only one usage of TASK_DEAD outside of last schedule path, select_bad_process: for_each_task(p) { if (!p->mm) continue; ... if (p->state == TASK_DEAD) continue; ... TASK_DEAD state is set at the end of do_exit(), this means that p->mm was already set == NULL by exit_mm(), so this task was already rejected by 'if (!p->mm)' above. Note also that the caller holds tasklist_lock, this means that p can't pass exit_notify() and then set TASK_DEAD when p->mm != NULL. Also, remove open-coded is_init(). Signed-off-by: Oleg Nesterov Cc: Ingo Molnar Cc: Nick Piggin Signed-off-by: Andrew Morton --- mm/oom_kill.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff -puN mm/oom_kill.c~select_bad_process-kill-a-bogus-pf_dead-task_dead-check mm/oom_kill.c --- a/mm/oom_kill.c~select_bad_process-kill-a-bogus-pf_dead-task_dead-check +++ a/mm/oom_kill.c @@ -206,11 +206,14 @@ static struct task_struct *select_bad_pr unsigned long points; int releasing; - /* skip kernel threads */ + /* + * skip kernel threads and tasks which have already released + * their mm. + */ if (!p->mm) continue; - /* skip the init task with pid == 1 */ - if (p->pid == 1) + /* skip the init task */ + if (is_init(p)) continue; /* @@ -226,9 +229,6 @@ static struct task_struct *select_bad_pr releasing = test_tsk_thread_flag(p, TIF_MEMDIE) || p->flags & PF_EXITING; if (releasing) { - /* TASK_DEAD tasks have already released their mm */ - if (p->state == TASK_DEAD) - continue; if (p->flags & PF_EXITING && p == current) { chosen = p; *ppoints = ULONG_MAX; _