[PATCH] futex_find_get_task(): remove an obscure EXIT_ZOMBIE check

futex_find_get_task:

	if (p->state == EXIT_ZOMBIE || p->exit_state == EXIT_ZOMBIE)
		return NULL;

I can't understand this.  First, p->state can't be EXIT_ZOMBIE.  The
->exit_state check looks strange too.  Sub-threads or tasks whose ->parent
ignores SIGCHLD go directly to EXIT_DEAD state (I am ignoring a ptrace
case).  Why EXIT_DEAD tasks should be ok?  Yes, EXIT_ZOMBIE is more
important (a task may stay zombie for a long time), but this doesn't mean
we should explicitely ignore other EXIT_XXX states.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/futex.c

@@ -397,7 +397,7 @@ static struct task_struct * futex_find_get_task(pid_t pid)
 		p = NULL;
 		goto out_unlock;
 	}
-	if (p->state == EXIT_ZOMBIE || p->exit_state == EXIT_ZOMBIE) {
+	if (p->exit_state != 0) {
 		p = NULL;
 		goto out_unlock;
 	}