Merge branch 'pm-powercap'

Merge power capping fixes for 6.19-rc2:

 - Fix CPU hotplug locking deadlock reported by lockdep after a recent
   update of the Intel RAPL power capping driver (Srinivas Pandruvada)

 - Fix sscanf() error return value handling in the power capping core
   and a race condition in register_control_type() (Sumeet Pawnikar)

* pm-powercap:
  powercap: intel_rapl: Fix possible recursive lock warning
  powercap: fix sscanf() error return value handling
  powercap: fix race condition in register_control_type()

Author: rafaeljw

drivers/powercap/intel_rapl_common.c

@@ -2032,16 +2032,14 @@ static int rapl_pmu_update(struct rapl_package *rp)
 	return ret;
 }
 
-int rapl_package_add_pmu(struct rapl_package *rp)
+int rapl_package_add_pmu_locked(struct rapl_package *rp)
 {
 	struct rapl_package_pmu_data *data = &rp->pmu_data;
 	int idx;
 
 	if (rp->has_pmu)
 		return -EEXIST;
 
-	guard(cpus_read_lock)();
-
 	for (idx = 0; idx < rp->nr_domains; idx++) {
 		struct rapl_domain *rd = &rp->domains[idx];
 		int domain = rd->id;
@@ -2091,17 +2089,23 @@ int rapl_package_add_pmu(struct rapl_package *rp)
 
 	return rapl_pmu_update(rp);
 }
+EXPORT_SYMBOL_GPL(rapl_package_add_pmu_locked);
+
+int rapl_package_add_pmu(struct rapl_package *rp)
+{
+	guard(cpus_read_lock)();
+
+	return rapl_package_add_pmu_locked(rp);
+}
 EXPORT_SYMBOL_GPL(rapl_package_add_pmu);
 
-void rapl_package_remove_pmu(struct rapl_package *rp)
+void rapl_package_remove_pmu_locked(struct rapl_package *rp)
 {
 	struct rapl_package *pos;
 
 	if (!rp->has_pmu)
 		return;
 
-	guard(cpus_read_lock)();
-
 	list_for_each_entry(pos, &rapl_packages, plist) {
 		/* PMU is still needed */
 		if (pos->has_pmu && pos != rp)
@@ -2111,6 +2115,14 @@ void rapl_package_remove_pmu(struct rapl_package *rp)
 	perf_pmu_unregister(&rapl_pmu.pmu);
 	memset(&rapl_pmu, 0, sizeof(struct rapl_pmu));
 }
+EXPORT_SYMBOL_GPL(rapl_package_remove_pmu_locked);
+
+void rapl_package_remove_pmu(struct rapl_package *rp)
+{
+	guard(cpus_read_lock)();
+
+	rapl_package_remove_pmu_locked(rp);
+}
 EXPORT_SYMBOL_GPL(rapl_package_remove_pmu);
 #endif
 

drivers/powercap/intel_rapl_msr.c

@@ -82,7 +82,7 @@ static int rapl_cpu_online(unsigned int cpu)
 		if (IS_ERR(rp))
 			return PTR_ERR(rp);
 		if (rapl_msr_pmu)
-			rapl_package_add_pmu(rp);
+			rapl_package_add_pmu_locked(rp);
 	}
 	cpumask_set_cpu(cpu, &rp->cpumask);
 	return 0;
@@ -101,7 +101,7 @@ static int rapl_cpu_down_prep(unsigned int cpu)
 	lead_cpu = cpumask_first(&rp->cpumask);
 	if (lead_cpu >= nr_cpu_ids) {
 		if (rapl_msr_pmu)
-			rapl_package_remove_pmu(rp);
+			rapl_package_remove_pmu_locked(rp);
 		rapl_remove_package_cpuslocked(rp);
 	} else if (rp->lead_cpu == cpu) {
 		rp->lead_cpu = lead_cpu;

drivers/powercap/powercap_sys.c

@@ -68,7 +68,7 @@ static ssize_t show_constraint_##_attr(struct device *dev, \
 	int id; \
 	struct powercap_zone_constraint *pconst;\
 	\
-	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
+	if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \
 		return -EINVAL; \
 	if (id >= power_zone->const_id_cnt)	\
 		return -EINVAL; \
@@ -93,7 +93,7 @@ static ssize_t store_constraint_##_attr(struct device *dev,\
 	int id; \
 	struct powercap_zone_constraint *pconst;\
 	\
-	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
+	if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \
 		return -EINVAL; \
 	if (id >= power_zone->const_id_cnt)	\
 		return -EINVAL; \
@@ -162,7 +162,7 @@ static ssize_t show_constraint_name(struct device *dev,
 	ssize_t len = -ENODATA;
 	struct powercap_zone_constraint *pconst;
 
-	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id))
+	if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1)
 		return -EINVAL;
 	if (id >= power_zone->const_id_cnt)
 		return -EINVAL;
@@ -625,17 +625,23 @@ struct powercap_control_type *powercap_register_control_type(
 	INIT_LIST_HEAD(&control_type->node);
 	control_type->dev.class = &powercap_class;
 	dev_set_name(&control_type->dev, "%s", name);
-	result = device_register(&control_type->dev);
-	if (result) {
-		put_device(&control_type->dev);
-		return ERR_PTR(result);
-	}
 	idr_init(&control_type->idr);
 
 	mutex_lock(&powercap_cntrl_list_lock);
 	list_add_tail(&control_type->node, &powercap_cntrl_list);
 	mutex_unlock(&powercap_cntrl_list_lock);
 
+	result = device_register(&control_type->dev);
+	if (result) {
+		mutex_lock(&powercap_cntrl_list_lock);
+		list_del(&control_type->node);
+		mutex_unlock(&powercap_cntrl_list_lock);
+
+		idr_destroy(&control_type->idr);
+		put_device(&control_type->dev);
+		return ERR_PTR(result);
+	}
+
 	return control_type;
 }
 EXPORT_SYMBOL_GPL(powercap_register_control_type);

include/linux/intel_rapl.h

@@ -214,10 +214,14 @@ void rapl_remove_package(struct rapl_package *rp);
 
 #ifdef CONFIG_PERF_EVENTS
 int rapl_package_add_pmu(struct rapl_package *rp);
+int rapl_package_add_pmu_locked(struct rapl_package *rp);
 void rapl_package_remove_pmu(struct rapl_package *rp);
+void rapl_package_remove_pmu_locked(struct rapl_package *rp);
 #else
 static inline int rapl_package_add_pmu(struct rapl_package *rp) { return 0; }
+static inline int rapl_package_add_pmu_locked(struct rapl_package *rp) { return 0; }
 static inline void rapl_package_remove_pmu(struct rapl_package *rp) { }
+static inline void rapl_package_remove_pmu_locked(struct rapl_package *rp) { }
 #endif
 
 #endif /* __INTEL_RAPL_H__ */