Merging upstream version 5.10.216.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index cc7cd512e..1b7c3bdba 100644
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -34,6 +34,8 @@
 	| MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK		\
 	| MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK)
 
+static DEFINE_MUTEX(membarrier_ipi_mutex);
+
 static void ipi_mb(void *info)
 {
 	smp_mb();	/* IPIs should be serializing but paranoid. */
@@ -119,6 +121,7 @@ static int membarrier_global_expedited(void)
 	if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
 		return -ENOMEM;
 
+	mutex_lock(&membarrier_ipi_mutex);
 	cpus_read_lock();
 	rcu_read_lock();
 	for_each_online_cpu(cpu) {
@@ -165,6 +168,8 @@ static int membarrier_global_expedited(void)
 	 * rq->curr modification in scheduler.
 	 */
 	smp_mb();	/* exit from system call is not a mb */
+	mutex_unlock(&membarrier_ipi_mutex);
+
 	return 0;
 }
 
@@ -208,6 +213,7 @@ static int membarrier_private_expedited(int flags, int cpu_id)
 	if (cpu_id < 0 && !zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
 		return -ENOMEM;
 
+	mutex_lock(&membarrier_ipi_mutex);
 	cpus_read_lock();
 
 	if (cpu_id >= 0) {
@@ -280,6 +286,7 @@ out:
 	 * rq->curr modification in scheduler.
 	 */
 	smp_mb();	/* exit from system call is not a mb */
+	mutex_unlock(&membarrier_ipi_mutex);
 
 	return 0;
 }
@@ -321,6 +328,7 @@ static int sync_runqueues_membarrier_state(struct mm_struct *mm)
 	 * between threads which are users of @mm has its membarrier state
 	 * updated.
 	 */
+	mutex_lock(&membarrier_ipi_mutex);
 	cpus_read_lock();
 	rcu_read_lock();
 	for_each_online_cpu(cpu) {
@@ -337,6 +345,7 @@ static int sync_runqueues_membarrier_state(struct mm_struct *mm)
 
 	free_cpumask_var(tmpmask);
 	cpus_read_unlock();
+	mutex_unlock(&membarrier_ipi_mutex);
 
 	return 0;
 }