From: Jon Medhurst (Tixy) Date: Wed, 15 Aug 2012 20:11:00 +0000 (+0200) Subject: cpuidle: Prevent null pointer dereference in cpuidle_coupled_cpu_notify X-Git-Tag: next-20120816~34^2 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1b2e203ac4113c558c31afe4dc2a88a5cfeabeb7;p=karo-tx-linux.git 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 Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c index c24dda03c143..3265844839bf 100644 --- a/drivers/cpuidle/coupled.c +++ b/drivers/cpuidle/coupled.c @@ -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) {