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tick/broadcast: Prevent NULL pointer dereference

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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 <slash.tmp@free.fr>
Signed-off-by: Thomas 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.fr
This commit is contained in:
Thomas Gleixner 2016-12-15 12:10:37 +01:00
parent f082f02c47
commit c1a9eeb938
1 changed files with 3 additions and 0 deletions
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3
kernel/time/tick-broadcast.c
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@ -871,6 +871,9 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{ {
int cpu = smp_processor_id(); int cpu = smp_processor_id();
if (!bc)
return;
/* Set it up only once ! */ /* Set it up only once ! */
if (bc->event_handler != tick_handle_oneshot_broadcast) { if (bc->event_handler != tick_handle_oneshot_broadcast) {
int was_periodic = clockevent_state_periodic(bc); int was_periodic = clockevent_state_periodic(bc);