diff --git a/[refs] b/[refs]
index e94470b394ed..711b08de43ea 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e4de866a834620ef974f5ba86d394a13d2f0cf66
+refs/heads/master: a43a5ccdfa5bd5b2f00aa9b2321df268c2e5d6e2
diff --git a/trunk/drivers/xen/xenbus/xenbus_dev_frontend.c b/trunk/drivers/xen/xenbus/xenbus_dev_frontend.c
index 527dc2a3b89f..89f76252a16f 100644
--- a/trunk/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/trunk/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -369,6 +369,10 @@ static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u)
 		goto out;
 	}
 	token++;
+	if (memchr(token, 0, u->u.msg.len - (token - path)) == NULL) {
+		rc = -EILSEQ;
+		goto out;
+	}
 
 	if (msg_type == XS_WATCH) {
 		watch = alloc_watch_adapter(path, token);