From 49cd9ac6a1929467e2df5783a5183fc7708ec3ff Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Mon, 11 Mar 2013 10:20:21 +0100
Subject: [PATCH] exec: assert that RAMBlock size is non-zero

find_ram_offset() does not handle size=0 gracefully.  It hands out the
same RAMBlock offset multiple times, leading to obscure failures later
on.

Add an assert to warn early if something is incorrectly allocating a
zero size RAMBlock.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 exec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/exec.c b/exec.c
index 8a6aac36e3..786987a016 100644
--- a/exec.c
+++ b/exec.c
@@ -925,6 +925,8 @@ static ram_addr_t find_ram_offset(ram_addr_t size)
     RAMBlock *block, *next_block;
     ram_addr_t offset = RAM_ADDR_MAX, mingap = RAM_ADDR_MAX;
 
+    assert(size != 0); /* it would hand out same offset multiple times */
+
     if (QTAILQ_EMPTY(&ram_list.blocks))
         return 0;
 
-- 
2.30.2