From: Oleg Nesterov The first "p->exit_state != EXIT_ZOMBIE" check doesn't make too much sense. The exit_state was EXIT_ZOMBIE when the function was called, and another thread can change it to EXIT_DEAD right after the check. The second condition is not possible, detached non-traced threads were already filtered out by eligible_child(), we didn't drop tasklist since then. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton --- kernel/exit.c | 4 ---- 1 file changed, 4 deletions(-) diff -puN kernel/exit.c~wait_task_zombie-remove-exit_state-exit_signal-checks-for-wnowait kernel/exit.c --- a/kernel/exit.c~wait_task_zombie-remove-exit_state-exit_signal-checks-for-wnowait +++ a/kernel/exit.c @@ -1192,10 +1192,6 @@ static int wait_task_zombie(struct task_ int exit_code = p->exit_code; int why, status; - if (unlikely(p->exit_state != EXIT_ZOMBIE)) - return 0; - if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) - return 0; get_task_struct(p); read_unlock(&tasklist_lock); if ((exit_code & 0x7f) == 0) { _