Merge tag 'pm-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These fix a NULL pointer dereference in a devfreq driver and a runtime
  PM framework issue that may cause a supplier device to be suspended
  before its consumer.

  Specifics:

   - Fix NULL pointer dereference related to printing a diagnostic
     message in the exynos-bus devfreq driver (Christian Marangi)

   - Fix race condition in the runtime PM framework which in some cases
     may cause a supplier device to be suspended when its consumer is
     still active (Rafael Wysocki)"

* tag 'pm-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / devfreq: exynos-bus: Fix NULL pointer dereference
  PM: runtime: Fix supplier device management during consumer probe
  PM: runtime: Redefine pm_runtime_release_supplier()

Author: torvalds

drivers/base/core.c

@@ -486,7 +486,18 @@ static void device_link_release_fn(struct work_struct *work)
 	/* Ensure that all references to the link object have been dropped. */
 	device_link_synchronize_removal();
 
-	pm_runtime_release_supplier(link, true);
+	pm_runtime_release_supplier(link);
+	/*
+	 * If supplier_preactivated is set, the link has been dropped between
+	 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
+	 * in __driver_probe_device().  In that case, drop the supplier's
+	 * PM-runtime usage counter to remove the reference taken by
+	 * pm_runtime_get_suppliers().
+	 */
+	if (link->supplier_preactivated)
+		pm_runtime_put_noidle(link->supplier);
+
+	pm_request_idle(link->supplier);
 
 	put_device(link->consumer);
 	put_device(link->supplier);

drivers/base/power/runtime.c

@@ -308,13 +308,10 @@ static int rpm_get_suppliers(struct device *dev)
 /**
  * pm_runtime_release_supplier - Drop references to device link's supplier.
  * @link: Target device link.
- * @check_idle: Whether or not to check if the supplier device is idle.
  *
- * Drop all runtime PM references associated with @link to its supplier device
- * and if @check_idle is set, check if that device is idle (and so it can be
- * suspended).
+ * Drop all runtime PM references associated with @link to its supplier device.
  */
-void pm_runtime_release_supplier(struct device_link *link, bool check_idle)
+void pm_runtime_release_supplier(struct device_link *link)
 {
 	struct device *supplier = link->supplier;
 
@@ -327,18 +324,18 @@ void pm_runtime_release_supplier(struct device_link *link, bool check_idle)
 	while (refcount_dec_not_one(&link->rpm_active) &&
 	       atomic_read(&supplier->power.usage_count) > 0)
 		pm_runtime_put_noidle(supplier);
-
-	if (check_idle)
-		pm_request_idle(supplier);
 }
 
 static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
 {
 	struct device_link *link;
 
 	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
-				device_links_read_lock_held())
-		pm_runtime_release_supplier(link, try_to_suspend);
+				device_links_read_lock_held()) {
+		pm_runtime_release_supplier(link);
+		if (try_to_suspend)
+			pm_request_idle(link->supplier);
+	}
 }
 
 static void rpm_put_suppliers(struct device *dev)
@@ -1771,7 +1768,6 @@ void pm_runtime_get_suppliers(struct device *dev)
 		if (link->flags & DL_FLAG_PM_RUNTIME) {
 			link->supplier_preactivated = true;
 			pm_runtime_get_sync(link->supplier);
-			refcount_inc(&link->rpm_active);
 		}
 
 	device_links_read_unlock(idx);
@@ -1791,19 +1787,8 @@ void pm_runtime_put_suppliers(struct device *dev)
 	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
 				device_links_read_lock_held())
 		if (link->supplier_preactivated) {
-			bool put;
-
 			link->supplier_preactivated = false;
-
-			spin_lock_irq(&dev->power.lock);
-
-			put = pm_runtime_status_suspended(dev) &&
-			      refcount_dec_not_one(&link->rpm_active);
-
-			spin_unlock_irq(&dev->power.lock);
-
-			if (put)
-				pm_runtime_put(link->supplier);
+			pm_runtime_put(link->supplier);
 		}
 
 	device_links_read_unlock(idx);
@@ -1838,7 +1823,8 @@ void pm_runtime_drop_link(struct device_link *link)
 		return;
 
 	pm_runtime_drop_link_count(link->consumer);
-	pm_runtime_release_supplier(link, true);
+	pm_runtime_release_supplier(link);
+	pm_request_idle(link->supplier);
 }
 
 static bool pm_runtime_need_not_resume(struct device *dev)

drivers/devfreq/exynos-bus.c

@@ -447,9 +447,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
 		}
 	}
 
-	max_state = bus->devfreq->profile->max_state;
-	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
-	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
+	max_state = bus->devfreq->max_state;
+	min_freq = (bus->devfreq->freq_table[0] / 1000);
+	max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000);
 	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
 			dev_name(dev), min_freq, max_freq);
 

include/linux/pm_runtime.h

@@ -88,7 +88,7 @@ extern void pm_runtime_get_suppliers(struct device *dev);
 extern void pm_runtime_put_suppliers(struct device *dev);
 extern void pm_runtime_new_link(struct device *dev);
 extern void pm_runtime_drop_link(struct device_link *link);
-extern void pm_runtime_release_supplier(struct device_link *link, bool check_idle);
+extern void pm_runtime_release_supplier(struct device_link *link);
 
 extern int devm_pm_runtime_enable(struct device *dev);
 
@@ -314,8 +314,7 @@ static inline void pm_runtime_get_suppliers(struct device *dev) {}
 static inline void pm_runtime_put_suppliers(struct device *dev) {}
 static inline void pm_runtime_new_link(struct device *dev) {}
 static inline void pm_runtime_drop_link(struct device_link *link) {}
-static inline void pm_runtime_release_supplier(struct device_link *link,
-					       bool check_idle) {}
+static inline void pm_runtime_release_supplier(struct device_link *link) {}
 
 #endif /* !CONFIG_PM */