From 868d075a9f580bb38b7a634e1a92d01fc9a4ca53 Mon Sep 17 00:00:00 2001
From: Florian Schmidt <florian.schmidt@neclab.eu>
Date: Thu, 21 Apr 2016 14:30:38 +0200
Subject: [PATCH] Fix null pointer derefence in non-debug builds

xenbus_get_self_id() calls xenbus_read within BUG_ON, but BUG_ON(x)
resolves to nothing in non-debug builds, removing the call. This made
sscanf dereference a null value.
---
 xenbus/xenbus.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/xenbus/xenbus.c b/xenbus/xenbus.c
index f74ed58..fccd1af 100644
--- a/xenbus/xenbus.c
+++ b/xenbus/xenbus.c
@@ -833,7 +833,9 @@ domid_t xenbus_get_self_id(void)
     char *dom_id;
     domid_t ret;
 
-    BUG_ON(xenbus_read(XBT_NIL, "domid", &dom_id));
+    if (xenbus_read(XBT_NIL, "domid", &dom_id)) {
+	    BUG_ON(1);
+    }
     sscanf(dom_id, "%"SCNd16, &ret);
 
     return ret;