| Message ID | 1344945151.2674.56.camel@linaro1.home (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tuesday, August 14, 2012, Jon Medhurst (Tixy) wrote: > 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> Applied to the linux-next branch of the linux-pm.git tree as v3.6 material. Thanks, Rafael > --- > > Would a better fix be to delay registering the notifier until > cpuidle_coupled_register_device() is called? Though following through > with that logic would require unregistering the notifier when cpuidle > driver is unregistered and it still seems possible that there would > still be a window of opportunity for things to go wrong. > > > drivers/cpuidle/coupled.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c > index 2c9bf26..c78a5ff 100644 > --- a/drivers/cpuidle/coupled.c > +++ b/drivers/cpuidle/coupled.c > @@ -681,7 +681,7 @@ 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) { >
diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c index 2c9bf26..c78a5ff 100644 --- a/drivers/cpuidle/coupled.c +++ b/drivers/cpuidle/coupled.c @@ -681,7 +681,7 @@ 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) {
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> --- Would a better fix be to delay registering the notifier until cpuidle_coupled_register_device() is called? Though following through with that logic would require unregistering the notifier when cpuidle driver is unregistered and it still seems possible that there would still be a window of opportunity for things to go wrong. drivers/cpuidle/coupled.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)