Fix inequality comparison against "task->state"

We should always use bitmask ops, rather than depend on some ordering of
the different states.  With the TASK_NONINTERACTIVE flag, the inequality
doesn't really work.

Oleg Nesterov argues (likely correctly) that this test is unnecessary in
the first place.  However, the minimal fix for now is to at least make
it work in the presense of TASK_NONINTERACTIVE.  Waiting for consensus
from Roland & co on potential bigger cleanups.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

kernel/exit.c

@@ -1203,7 +1203,7 @@ static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap,
 
 		exit_code = p->exit_code;
 		if (unlikely(!exit_code) ||
-		    unlikely(p->state > TASK_STOPPED))
+		    unlikely(p->state & TASK_TRACED))
 			goto bail_ref;
 		return wait_noreap_copyout(p, pid, uid,
 					   why, (exit_code << 8) | 0x7f,