diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3070164e203663c89848840c6dda8029a3829e02..998ab5957c6a3775a23d833206072a86945effc8 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1770,9 +1770,9 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
 		return 0;
 	}
 
-	start = buf + buflen;
+	start = buf + buflen - 1;
 
-	*--start = '\0';
+	*start = '\0';
 	for (;;) {
 		int len = dentry->d_name.len;