diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 711fa17..27d062e 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1269,7 +1269,9 @@
 
 	/* do we need to enable the supply regulator first */
 	if (rdev->supply) {
+		mutex_lock(&rdev->supply->mutex);
 		ret = _regulator_enable(rdev->supply);
+		mutex_unlock(&rdev->supply->mutex);
 		if (ret < 0) {
 			printk(KERN_ERR "%s: failed to enable %s: %d\n",
 			       __func__, rdev_get_name(rdev), ret);