Re: [PATCH v2 01/20] parallels: Set s->used_bmap to NULL in parallels_free_used_bitmap()

[Mike Maslenkin <mike.maslenkin@gmail.com>]

On Thu, Oct 19, 2023 at 4:06 PM Alexander Ivanov
<alexander.ivanov@virtuozzo.com> wrote:
>
> After used bitmap freeng s->used_bmap points to the freed memory. If we try
> to free used bitmap one more time it leads to double free error.
>
> Set s->used_bmap to NULL to exclude double free error.
>
> Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
> ---
>  block/parallels.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/block/parallels.c b/block/parallels.c
> index 6b46623241..ba1fdde259 100644
> --- a/block/parallels.c
> +++ b/block/parallels.c
> @@ -244,6 +244,7 @@ static void parallels_free_used_bitmap(BlockDriverState *bs)
>  {
>      BDRVParallelsState *s = bs->opaque;
>      s->used_bmap_size = 0;
> +    s->used_bmap = NULL;
>      g_free(s->used_bmap);
>  }

Shouldn't it be added after g_free() call?

Regards,
Mike.