[PATCH] Fix yenta-socket oops

From: Russell King <rmk@arm.linux.org.uk>

Interrupts can sometimes occur before the socket thread is started.

drivers/pcmcia/cs.c

@@ -868,13 +868,19 @@ static int pccardd(void *__skt)
 	complete_and_exit(&skt->thread_done, 0);
 }
 
+/*
+ * Yenta (at least) probes interrupts before registering the socket and
+ * starting the handler thread.
+ */
 void pcmcia_parse_events(struct pcmcia_socket *s, u_int events)
 {
-	spin_lock(&s->thread_lock);
-	s->thread_events |= events;
-	spin_unlock(&s->thread_lock);
+	if (s->thread) {
+		spin_lock(&s->thread_lock);
+		s->thread_events |= events;
+		spin_unlock(&s->thread_lock);
 
-	wake_up(&s->thread_wait);
+		wake_up(&s->thread_wait);
+	}
 } /* pcmcia_parse_events */