[Qemu-block] [PATCH] qcow2: always initialize specific image info

[Roman Kagan]

qcow2_get_specific_info() used to have a code path which would leave
pointer to ImageInfoSpecificQCow2 uninitialized.

We guess that it caused sporadic crashes on freeing an invalid pointer
in response to "query-block" QMP command in
visit_type_ImageInfoSpecificQCow2 with QapiDeallocVisitor.

Although we have neither a solid proof nor a reproduction scenario,
making sure the field is initialized appears a reasonable thing to do.

Signed-off-by: Roman Kagan <address@hidden>
---
 block/qcow2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 88f56c8..67c9d3d 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2739,7 +2739,7 @@ static ImageInfoSpecific 
*qcow2_get_specific_info(BlockDriverState *bs)
 
     *spec_info = (ImageInfoSpecific){
         .type  = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
-        .u.qcow2 = g_new(ImageInfoSpecificQCow2, 1),
+        .u.qcow2 = g_new0(ImageInfoSpecificQCow2, 1),
     };
     if (s->qcow_version == 2) {
         *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){
-- 
2.5.0