From 63c6ba4352009a5f85b32307c001abeb5baebd28 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Wed, 15 Aug 2012 22:10:50 +0200 Subject: cpuidle: coupled: fix sleeping while atomic in cpu notifier The cpu hotplug notifier gets called in both atomic and non-atomic contexts, it is not always safe to lock a mutex. Filter out all events except the six necessary ones, which are all sleepable, before taking the mutex. Signed-off-by: Colin Cross Reviewed-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/coupled.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'drivers/cpuidle/coupled.c') diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c index 2c9bf2692232..c24dda03c143 100644 --- a/drivers/cpuidle/coupled.c +++ b/drivers/cpuidle/coupled.c @@ -678,6 +678,18 @@ static int cpuidle_coupled_cpu_notify(struct notifier_block *nb, int cpu = (unsigned long)hcpu; struct cpuidle_device *dev; + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_UP_PREPARE: + case CPU_DOWN_PREPARE: + case CPU_ONLINE: + case CPU_DEAD: + case CPU_UP_CANCELED: + case CPU_DOWN_FAILED: + break; + default: + return NOTIFY_OK; + } + mutex_lock(&cpuidle_lock); dev = per_cpu(cpuidle_devices, cpu); -- cgit v1.2.3 From 5fbbb90dfdedb9a258550e4e5debd3013266372e Mon Sep 17 00:00:00 2001 From: "Jon Medhurst (Tixy)" Date: Wed, 15 Aug 2012 22:11:00 +0200 Subject: 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 --- drivers/cpuidle/coupled.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/cpuidle/coupled.c') 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) { -- cgit v1.2.3