Re: [PATCH] net/virtio-user: fix control queue allocation for non-vDPA

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 7/3/24 18:27, Maxime Coquelin wrote:
> For non-vDPA backends, where the backend does not support
> control queue, it is still emulated in the Virtio-user
> layer to handle multiqueue feature. The frontend setups a
> control queue, which is hidden to the device. It means the
> number of vrings metadata to allocate should be based on
> the frontend features and not the device features.
> 
> This patch fixes out-of-range access reported by ASan,
> which could sometimes be noticed at exit time by a
> segmentation fault when disabled:
> 
> Fixes: b80947743f5e ("net/virtio-user: fix control queue allocation")
> 
> Reported-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>   drivers/net/virtio/virtio_user/virtio_user_dev.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index b2c6c2b7df..fed66d2ae9 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -624,7 +624,7 @@ virtio_user_alloc_vrings(struct virtio_user_dev *dev)
>   	bool packed_ring = !!(dev->device_features & (1ull << VIRTIO_F_RING_PACKED));
>   
>   	nr_vrings = dev->max_queue_pairs * 2;
> -	if (dev->device_features & (1ull << VIRTIO_NET_F_CTRL_VQ))
> +	if (dev->frontend_features & (1ull << VIRTIO_NET_F_CTRL_VQ))
>   		nr_vrings++;
>   
>   	dev->callfds = rte_zmalloc("virtio_user_dev", nr_vrings * sizeof(*dev->callfds), 0);

Applied to next-virtio/for-next-net.

Thanks for the review,
Maxime