From 40f73f9e5e947903712839caccf07ce4a97e814f Mon Sep 17 00:00:00 2001
From: Keir Fraser <keir.fraser@citrix.com>
Date: Tue, 17 Mar 2009 15:40:25 +0000
Subject: [PATCH] x86: Assert non-zero refcount on entry to put_page().
 Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

---
 xen/arch/x86/mm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 4f58720fed..7752d1a3a0 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1929,6 +1929,7 @@ void put_page(struct page_info *page)
     unsigned long nx, x, y = page->count_info;
 
     do {
+        ASSERT((y & PGC_count_mask) != 0);
         x  = y;
         nx = x - 1;
     }
-- 
2.39.5