diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 3424b19..3a57679 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -2211,11 +2211,13 @@
 static ssize_t can_clear_show(struct mddev *mddev, char *page)
 {
 	int len;
+	spin_lock(&mddev->lock);
 	if (mddev->bitmap)
 		len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
 					     "false" : "true"));
 	else
 		len = sprintf(page, "\n");
+	spin_unlock(&mddev->lock);
 	return len;
 }
 
@@ -2240,10 +2242,15 @@
 static ssize_t
 behind_writes_used_show(struct mddev *mddev, char *page)
 {
+	ssize_t ret;
+	spin_lock(&mddev->lock);
 	if (mddev->bitmap == NULL)
-		return sprintf(page, "0\n");
-	return sprintf(page, "%lu\n",
-		       mddev->bitmap->behind_writes_used);
+		ret = sprintf(page, "0\n");
+	else
+		ret = sprintf(page, "%lu\n",
+			      mddev->bitmap->behind_writes_used);
+	spin_unlock(&mddev->lock);
+	return ret;
 }
 
 static ssize_t