[PULL 03/27] vmstate: Fix memory leak in vmstate_handle_alloc()

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: Jinhao Gao <gaojinhao@huawei.com>

Some memory allocated for fields having a flag of VMS_ALLOC in SaveState
may not free before VM load vmsd in migration. So we pre-free memory before
allocation in vmstate_handle_alloc() to avoid memleaks.

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Jinhao Gao <gaojinhao@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20201231061020.828-4-gaojinhao@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/vmstate.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/migration/vmstate.c b/migration/vmstate.c
index 05f87cdddc..cc3dfcbae8 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -70,6 +70,7 @@ static void vmstate_handle_alloc(void *ptr, const VMStateField *field,
         gsize size = vmstate_size(opaque, field);
         size *= vmstate_n_elems(opaque, field);
         if (size) {
+            g_free(*(void **)ptr);
             *(void **)ptr = g_malloc(size);
         }
     }
-- 
2.29.2