[PATCH] console blanking oops fix

When significant delays happen during boot (e.g.  with a kernel debugger,
but the problem has also seen in other cases) the timeout for blanking the
console may trigger, but the work scheduler may not have been initialized,
yet.  schedule_work() will oops over the null keventd_wq.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/char/vt.c

@@ -2867,6 +2867,10 @@ void unblank_screen(void)
  */
 static void blank_screen_t(unsigned long dummy)
 {
+	if (unlikely(!keventd_up())) {
+		mod_timer(&console_timer, jiffies + blankinterval);
+		return;
+	}
 	blank_timer_expired = 1;
 	schedule_work(&console_work);
 }