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cpuidle: Prevent null pointer dereference in cpuidle_coupled_cpu_notify 

When a kernel is built to support multiple hardware types it's possible
that CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED is set but the hardware the
kernel is run on doesn't support cpuidle and therefore doesn't load a
driver for it. In this case, when the system is shut down,
cpuidle_coupled_cpu_notify() gets called with cpuidle_devices set to
NULL. There are quite possibly other circumstances where this
situation can also occur and we should check for it.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Jon Medhurst (Tixy) 2012-08-15 22:11:00 +02:00 committed by Rafael J. Wysocki
parent 63c6ba4352
commit 5fbbb90dfd
1 changed files with 1 additions and 1 deletions
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2
drivers/cpuidle/coupled.c
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@ -693,7 +693,7 @@ static int cpuidle_coupled_cpu_notify(struct notifier_block *nb,
mutex_lock(&cpuidle_lock);
dev = per_cpu(cpuidle_devices, cpu);
if (!dev->coupled)
if (!dev || !dev->coupled)
goto out;
switch (action & ~CPU_TASKS_FROZEN) {