clockevents: Set noop handler in clockevents_exchange_device()

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 <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index e4c699dfa4e8776ee3ed9e671922e962002b6a06..13dfaaba4061338c14ebf022880f9cbf5defe776 100644 (file)
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -286,6 +286,7 @@ void clockevents_exchange_device(struct clock_event_device *old,
         * 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);