[Qemu-devel] [PATCH 2/2] exec: assert that RAMBlock size is non-zero

[Stefan Hajnoczi <stefanha@redhat.com>]

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>
---
 exec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/exec.c b/exec.c
index 46a2830..a9aa703 100644
--- a/exec.c
+++ b/exec.c
@@ -912,6 +912,8 @@ 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;
 
-- 
1.8.1.4