diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 974dc589ce0e0..b45ab455a18e8 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -30,6 +30,7 @@ struct memtrace_entry {
 	char name[16];
 };
 
+static DEFINE_MUTEX(memtrace_mutex);
 static u64 memtrace_size;
 
 static struct memtrace_entry *memtrace_array;
@@ -290,6 +291,7 @@ static int memtrace_online(void)
 
 static int memtrace_enable_set(void *data, u64 val)
 {
+	int rc = -EAGAIN;
 	u64 bytes;
 
 	/*
@@ -302,25 +304,31 @@ static int memtrace_enable_set(void *data, u64 val)
 		return -EINVAL;
 	}
 
+	mutex_lock(&memtrace_mutex);
+
 	/* Re-add/online previously removed/offlined memory */
 	if (memtrace_size) {
 		if (memtrace_online())
-			return -EAGAIN;
+			goto out_unlock;
 	}
 
-	if (!val)
-		return 0;
+	if (!val) {
+		rc = 0;
+		goto out_unlock;
+	}
 
 	/* Offline and remove memory */
 	if (memtrace_init_regions_runtime(val))
-		return -EINVAL;
+		goto out_unlock;
 
 	if (memtrace_init_debugfs())
-		return -EINVAL;
+		goto out_unlock;
 
 	memtrace_size = val;
-
-	return 0;
+	rc = 0;
+out_unlock:
+	mutex_unlock(&memtrace_mutex);
+	return rc;
 }
 
 static int memtrace_enable_get(void *data, u64 *val)