2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <redacted>

commit de28f25e8244c7353abed8de0c7792f5f883588c upstream.

If a device is shutdown, then there might be a pending interrupt,
which will be processed after we reenable interrupts, which causes the
original handler to be run. If the old handler is the (broadcast)
periodic handler the shutdown state might hang the kernel completely.

Signed-off-by: Thomas Gleixner <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 kernel/time/clockevents.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c

@@ -221,6 +221,7 @@ void clockevents_exchange_device(struct
 	 * released list and do a notify add later.
 	 */
 	if (old) {
+		old->event_handler = clockevents_handle_noop;
 		clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
 		list_del(&old->list);
 		list_add(&old->list, &clockevents_released);