| From c1a9eeb938b5433947e5ea22f89baff3182e7075 Mon Sep 17 00:00:00 2001 |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Thu, 15 Dec 2016 12:10:37 +0100 |
| Subject: tick/broadcast: Prevent NULL pointer dereference |
| |
| From: Thomas Gleixner <tglx@linutronix.de> |
| |
| commit c1a9eeb938b5433947e5ea22f89baff3182e7075 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: 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 |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/time/tick-broadcast.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/kernel/time/tick-broadcast.c |
| +++ b/kernel/time/tick-broadcast.c |
| @@ -871,6 +871,9 @@ void tick_broadcast_setup_oneshot(struct |
| { |
| 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); |
