signals: collect_signal: remove the unneeded sigismember() check

collect_signal() checks sigismember(&list->signal, sig), this is not
needed.  This "sig" was just found by next_signal(), so it must be valid.

We have a (completely broken) call to ->notifier in between, but it must
not play with sigpending->signal bits or unlock ->siglock.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/signal.c

@@ -343,9 +343,6 @@ static int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
 	struct sigqueue *q, *first = NULL;
 	int still_pending = 0;
 
-	if (unlikely(!sigismember(&list->signal, sig)))
-		return 0;
-
 	/*
 	 * Collect the siginfo appropriate to this signal.  Check if
 	 * there is another siginfo for the same signal.