Re: [Qemu-devel] [PATCH v4 7/7] block/nbd: NBDReply is used being uninitialized

[Eric Blake <eblake@redhat.com>]

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On 7/19/19 4:40 AM, Andrey Shinkevich wrote:
> In case nbd_co_receive_one_chunk() fails in
> nbd_reply_chunk_iter_receive(), 'NBDReply reply' parameter is used in
> the check nbd_reply_is_simple() without being initialized. The iotest
> 083 does not pass under the Valgrind: $./check -nbd -valgrind 083.
> The alternative solution is to swap the operands in the condition:
> 'if (s->quit || nbd_reply_is_simple(reply))'
> 
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>  block/nbd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Huh. Very similar to
https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg03712.html, but
affects a different function. I can queue this one through my NBD tree
to get both in my rc2 pull request.

Reviewed-by: Eric Blake <eblake@redhat.com>

> 
> diff --git a/block/nbd.c b/block/nbd.c
> index 81edabb..8480ad4 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -786,7 +786,7 @@ static int nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t handle,
>                                          int *request_ret, Error **errp)
>  {
>      NBDReplyChunkIter iter;
> -    NBDReply reply;
> +    NBDReply reply = {};
>      void *payload = NULL;
>      Error *local_err = NULL;
>  
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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