Re: [PATCH 0/8] Fix memory leak of some device state in migration

[Michael S. Tsirkin]

On Sat, Dec 26, 2020 at 06:33:39PM +0800, g00517791 wrote:
> From: Jinhao Gao <gaojinhao@huawei.com>
> 
> For some device state having some fields of VMS_ALLOC flag, they don't
> free memory allocated for the fields in vmstate_save_state and vmstate
> _load_state. We add funcs or sentences of free memory before allocation
> of memory or after load of memory to avoid memory leak.
> 

Isn't there a way to handle it centrally?
IIUC the issue is repeated loads in case a load fails, right?
So can't we do something along the lines of:

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/migration/vmstate.c b/migration/vmstate.c
index e9d2aef66b..873f76739f 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);
         }
     }

-- 
MST