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tick/broadcast: Prevent NULL pointer dereference
authorThomas Gleixner <tglx@linutronix.de>
Thu, 15 Dec 2016 11:10:37 +0000 (12:10 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 12 Jan 2017 10:39:45 +0000 (11:39 +0100)
commitcf365b117388a50902d56988e69dd6f70b7662fc
treeb9e8681010b1451d89deb7b85ae31fce3b463278
parent34db201f0de7138d3646946f5d33e178c93efca6
tick/broadcast: Prevent NULL pointer dereference

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