Merge tag 'pm-4.19-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power management updates from Rafael Wysocki:
 "These fix the main idle loop and the menu cpuidle governor, clean up
  the latter, fix a mistake in the PCI bus type's support for system
  suspend and resume, fix the ondemand and conservative cpufreq
  governors, address a build issue in the system wakeup framework and
  make the ACPI C-states desciptions less confusing.

  Specifics:

   - Make the idle loop handle stopped scheduler tick correctly (Rafael
     Wysocki).

   - Prevent the menu cpuidle governor from letting CPUs spend too much
     time in shallow idle states when it is invoked with scheduler tick
     stopped and clean it up somewhat (Rafael Wysocki).

   - Avoid invoking the platform firmware to make the platform enter the
     ACPI S3 sleep state with suspended PCIe root ports which may
     confuse the firmware and cause it to crash (Rafael Wysocki).

   - Fix sysfs-related race in the ondemand and conservative cpufreq
     governors which may cause the system to crash if the governor
     module is removed during an update of CPU frequency limits (Henry
     Willard).

   - Select SRCU when building the system wakeup framework to avoid a
     build issue in it (zhangyi).

   - Make the descriptions of ACPI C-states vendor-neutral to avoid
     confusion (Prarit Bhargava)"

* tag 'pm-4.19-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpuidle: menu: Handle stopped tick more aggressively
  sched: idle: Avoid retaining the tick when it has been stopped
  PCI / ACPI / PM: Resume all bridges on suspend-to-RAM
  cpuidle: menu: Update stale polling override comment
  cpufreq: governor: Avoid accessing invalid governor_data
  x86/ACPI/cstate: Make APCI C1 FFH MWAIT C-state description vendor-neutral
  cpuidle: menu: Fix white space
  PM / sleep: wakeup: Fix build error caused by missing SRCU support

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 1d50e97d49f1..6d53f7d9fc7a 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -555,12 +555,20 @@ EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_stop);
 
 void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy)
 {
-	struct policy_dbs_info *policy_dbs = policy->governor_data;
+	struct policy_dbs_info *policy_dbs;
+
+	/* Protect gov->gdbs_data against cpufreq_dbs_governor_exit() */
+	mutex_lock(&gov_dbs_data_mutex);
+	policy_dbs = policy->governor_data;
+	if (!policy_dbs)
+		goto out;
 
 	mutex_lock(&policy_dbs->update_mutex);
 	cpufreq_policy_apply_limits(policy);
 	gov_update_sample_delay(policy_dbs, 0);
-
 	mutex_unlock(&policy_dbs->update_mutex);
+
+out:
+	mutex_unlock(&gov_dbs_data_mutex);
 }
 EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_limits);