From 640f891eb258563bb155e577389e8c5e6541a59a Mon Sep 17 00:00:00 2001
From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Thu, 21 May 2015 08:57:19 +0200
Subject: [PATCH] vmap: avoid hitting an ASSERT with vfree(NULL)
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and unconditionally defer the vm_size() call, as it doesn't have a NULL
short circuit.

Reported-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
---
 xen/common/vmap.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/common/vmap.c b/xen/common/vmap.c
index 8752595cdb..ac66a8c41b 100644
--- a/xen/common/vmap.c
+++ b/xen/common/vmap.c
@@ -268,10 +268,14 @@ void *vzalloc(size_t size)
 
 void vfree(void *va)
 {
-    unsigned int i, pages = vm_size(va);
+    unsigned int i, pages;
     struct page_info *pg;
     PAGE_LIST_HEAD(pg_list);
 
+    if ( !va )
+        return;
+
+    pages = vm_size(va);
     ASSERT(pages);
 
     for ( i = 0; i < pages; i++ )
-- 
2.30.2