> -----Original Message-----
> From: Alexander Chernavin <acherna...@netgate.com>
> Sent: Wednesday, August 31, 2022 4:54 PM
> To: maxime.coque...@redhat.com; Xia, Chenbo <chenbo....@intel.com>
> Cc: dev@dpdk.org; Alexander Chernavin <acherna...@netgate.com>
> Subject: [PATCH] net/virtio: fix crash when dev is configured twice
>
> When first attempt to configure a device with RX interrupt enabled fails
> for some reason (e.g. because "Multiple intr vector not supported"),
> second attempt to configure the device with RX interrupt disabled and
> feature set unchanged will succeed but will leave virtio queues not
> allocated. Accessing the queues will cause a segfault.
>
> First attempt:
> - virtio_dev_configure()
> - virtio_init_device() is called to reinit the device because
> "dev->data->dev_conf.intr_conf.rxq" is "1"
> - virtio_configure_intr() fails and returns an error
> - virtio_free_queues() frees previously allocated virtio queues
> - virtio_init_device() fails and returns an error
> - virtio_dev_configure() fails and returns an error
>
> Second attempt:
> - virtio_dev_configure()
> - This time virtio_init_device() is not called, virtio queues
> are not allocated
>
> With this fix, reinit the device during configuration if virtio queues
> are not allocated.
Good catch. This is a fix, we should backport it, let's add fix and cc-stable
Tag.
Thanks,
Chenbo
>
> Signed-off-by: Alexander Chernavin <acherna...@netgate.com>
> ---
> drivers/net/virtio/virtio_ethdev.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> index d180162abd..38bfe050b5 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -2616,6 +2616,13 @@ virtio_dev_configure(struct rte_eth_dev *dev)
> return ret;
> }
>
> + /* if queues are not allocated, reinit the device */
> + if (hw->vqs == NULL) {
> + ret = virtio_init_device(dev, hw->req_guest_features);
> + if (ret < 0)
> + return ret;
> + }
> +
> if ((rxmode->mq_mode & RTE_ETH_MQ_RX_RSS_FLAG) &&
> !virtio_with_feature(hw, VIRTIO_NET_F_RSS)) {
> PMD_DRV_LOG(ERR, "RSS support requested but not supported by
> the device");
> --
> 2.25.1
