Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Thomas Gleixner:
 "A single bug fix to prevent a subtle deadlock in the scheduler core
  code vs cpu hotplug"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Fix cpu.max vs. cpuhotplug deadlock

2 files changed, 11 insertions, 5 deletions

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 8594d24e4adc..b4517095db6a 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -79,7 +79,7 @@ int static_key_count(struct static_key *key)
 }
 EXPORT_SYMBOL_GPL(static_key_count);
 
-static void static_key_slow_inc_cpuslocked(struct static_key *key)
+void static_key_slow_inc_cpuslocked(struct static_key *key)
 {
 	int v, v1;
 
@@ -180,7 +180,7 @@ void static_key_disable(struct static_key *key)
 }
 EXPORT_SYMBOL_GPL(static_key_disable);
 
-static void static_key_slow_dec_cpuslocked(struct static_key *key,
+static void __static_key_slow_dec_cpuslocked(struct static_key *key,
 					   unsigned long rate_limit,
 					   struct delayed_work *work)
 {
@@ -211,7 +211,7 @@ static void __static_key_slow_dec(struct static_key *key,
 				  struct delayed_work *work)
 {
 	cpus_read_lock();
-	static_key_slow_dec_cpuslocked(key, rate_limit, work);
+	__static_key_slow_dec_cpuslocked(key, rate_limit, work);
 	cpus_read_unlock();
 }
 
@@ -229,6 +229,12 @@ void static_key_slow_dec(struct static_key *key)
 }
 EXPORT_SYMBOL_GPL(static_key_slow_dec);
 
+void static_key_slow_dec_cpuslocked(struct static_key *key)
+{
+	STATIC_KEY_CHECK_USE(key);
+	__static_key_slow_dec_cpuslocked(key, 0, NULL);
+}
+
 void static_key_slow_dec_deferred(struct static_key_deferred *key)
 {
 	STATIC_KEY_CHECK_USE(key);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2fe3aa853e4d..26a71ebcd3c2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4365,12 +4365,12 @@ static inline bool cfs_bandwidth_used(void)
 
 void cfs_bandwidth_usage_inc(void)
 {
-	static_key_slow_inc(&__cfs_bandwidth_used);
+	static_key_slow_inc_cpuslocked(&__cfs_bandwidth_used);
 }
 
 void cfs_bandwidth_usage_dec(void)
 {
-	static_key_slow_dec(&__cfs_bandwidth_used);
+	static_key_slow_dec_cpuslocked(&__cfs_bandwidth_used);
 }
 #else /* HAVE_JUMP_LABEL */
 static bool cfs_bandwidth_used(void)