diff --git a/[refs] b/[refs]
index 9882b265b53a..676f2e308264 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 48a23fac5eb0030a2d578ee2bde21b6e035b3d57
+refs/heads/master: 740924a267e85de09707ea158bbf594b4d8bae01
diff --git a/trunk/drivers/pinctrl/pinmux.c b/trunk/drivers/pinctrl/pinmux.c
index 1a00658b3ea0..bd83c8b01cd1 100644
--- a/trunk/drivers/pinctrl/pinmux.c
+++ b/trunk/drivers/pinctrl/pinmux.c
@@ -194,6 +194,11 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 	}
 
 	if (!gpio_range) {
+		/*
+		 * A pin should not be freed more times than allocated.
+		 */
+		if (WARN_ON(!desc->mux_usecount))
+			return NULL;
 		desc->mux_usecount--;
 		if (desc->mux_usecount)
 			return NULL;