diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fd1b707f5de4..110afda740a1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4880,9 +4880,12 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
 	buf = endp + 1;
 
 	cfd = simple_strtoul(buf, &endp, 10);
-	if ((*endp != ' ') && (*endp != '\0'))
+	if (*endp == '\0')
+		buf = endp;
+	else if (*endp == ' ')
+		buf = endp + 1;
+	else
 		return -EINVAL;
-	buf = endp + 1;
 
 	event = kzalloc(sizeof(*event), GFP_KERNEL);
 	if (!event)