tick/broadcast: Prevent NULL pointer dereference

When a disfunctional timer, e.g. dummy timer, is installed, the tick core
tries to setup the broadcast timer.

If no broadcast device is installed, the kernel crashes with a NULL pointer
dereference in tick_broadcast_setup_oneshot() because the function has no
sanity check.

Reported-by: Mason <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Anna-Maria Gleixner <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Peter Zijlstra <[email protected]>,
Cc: Sebastian Frias <[email protected]>
Cc: Thibaud Cornic <[email protected]>
Cc: Robin Murphy <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index f6aae7977824ab7595950e378c2dd0f0bbe0256d..d2a20e83ebaed372ddb68d00bd8f44a50989b804 100644 (file)
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -871,6 +871,9 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
        int cpu = smp_processor_id();
 
+       if (!bc)
+               return;
+
        /* Set it up only once ! */
        if (bc->event_handler != tick_handle_oneshot_broadcast) {
                int was_periodic = clockevent_state_periodic(bc);