diff options
| author | Stuart Hayes <Stuart_Hayes@Dell.com> | 2012-06-13 16:10:45 -0500 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2012-06-30 00:51:13 -0400 |
| commit | 5f1601261050251a5ca293378b492a69d590dacb (patch) | |
| tree | e2395916caa5bc1ab2a3b28770f6433551e3b16f | |
| parent | 76e10d158efb6d4516018846f60c2ab5501900bc (diff) | |
| download | lwn-5f1601261050251a5ca293378b492a69d590dacb.tar.gz lwn-5f1601261050251a5ca293378b492a69d590dacb.zip | |
acpi_pad: fix power_saving thread deadlock
The acpi_pad driver can get stuck in destroy_power_saving_task()
waiting for kthread_stop() to stop a power_saving thread. The problem
is that the isolated_cpus_lock mutex is owned when
destroy_power_saving_task() calls kthread_stop(), which waits for a
power_saving thread to end, and the power_saving thread tries to
acquire the isolated_cpus_lock when it calls round_robin_cpu(). This
patch fixes the issue by making round_robin_cpu() use its own mutex.
https://bugzilla.kernel.org/show_bug.cgi?id=42981
Cc: stable@vger.kernel.org
Signed-off-by: Stuart Hayes <Stuart_Hayes@Dell.com>
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | drivers/acpi/acpi_pad.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c index a43fa1a57d57..1502c50273b5 100644 --- a/drivers/acpi/acpi_pad.c +++ b/drivers/acpi/acpi_pad.c @@ -36,6 +36,7 @@ #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 static DEFINE_MUTEX(isolated_cpus_lock); +static DEFINE_MUTEX(round_robin_lock); static unsigned long power_saving_mwait_eax; @@ -107,7 +108,7 @@ static void round_robin_cpu(unsigned int tsk_index) if (!alloc_cpumask_var(&tmp, GFP_KERNEL)) return; - mutex_lock(&isolated_cpus_lock); + mutex_lock(&round_robin_lock); cpumask_clear(tmp); for_each_cpu(cpu, pad_busy_cpus) cpumask_or(tmp, tmp, topology_thread_cpumask(cpu)); @@ -116,7 +117,7 @@ static void round_robin_cpu(unsigned int tsk_index) if (cpumask_empty(tmp)) cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus); if (cpumask_empty(tmp)) { - mutex_unlock(&isolated_cpus_lock); + mutex_unlock(&round_robin_lock); return; } for_each_cpu(cpu, tmp) { @@ -131,7 +132,7 @@ static void round_robin_cpu(unsigned int tsk_index) tsk_in_cpu[tsk_index] = preferred_cpu; cpumask_set_cpu(preferred_cpu, pad_busy_cpus); cpu_weight[preferred_cpu]++; - mutex_unlock(&isolated_cpus_lock); + mutex_unlock(&round_robin_lock); set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu)); } |