Re: [Qemu-devel] [Qemu-block] [PATCH] migration/block-dirty-bitmap: fix Coverity CID1390625

[Stefan Hajnoczi]

On Tue, Oct 16, 2018 at 04:20:18PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> Theoretically possible that we finish the skipping loop with bs = NULL
> and the following code will crash trying to dereference it. Fix that.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
>  migration/block-dirty-bitmap.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
> index 477826330c..6de808f95f 100644
> --- a/migration/block-dirty-bitmap.c
> +++ b/migration/block-dirty-bitmap.c
> @@ -288,6 +288,10 @@ static int init_dirty_bitmap_migration(void)
>              bs = backing_bs(bs);
>          }
>  
> +        if (!bs || bs->implicit) {
> +            continue;
> +        }
> +
>          for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap;
>               bitmap = bdrv_dirty_bitmap_next(bs, bitmap))
>          {

Previous discussion:
http://qemu.11.n7.nabble.com/PATCH-migration-Appease-coverity-skip-empty-block-trees-td582504.html

I've CCed John so he can take a look.

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