Re: [PATCH v3 3/3] vmstate: Fix memory leak in vmstate_handle_alloc()

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

* Jinhao Gao (gaojinhao@huawei.com) wrote:
> 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>

Yes, I think that's OK; it's actually pretty rare for this to happen;
normally inwards migrations either succeed or fail and exit; doing
multiple loads from snapshots is valid and I guess COLO hits this as well.

Reviewed-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 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);
>          }
>      }
> -- 
> 2.23.0
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK