Commit 6053479c authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Greg Kroah-Hartman

tick/broadcast: Prevent NULL pointer dereference

commit c1a9eeb9 upstream.

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: default avatarMason <slash.tmp@free.fr>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Richard Cochran <rcochran@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Cc: Sebastian Frias <sf84@laposte.net>
Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.frSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent af817b3f
......@@ -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);
......
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