On Thu, Mar 30, 2023 at 12:03 AM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:
>
> Initialization must be completed before calling _vdpa_register_device()
> since it can connect the device to the vDPA bus, so requests can arrive
> after that call.
>
> So for example vdpasim_net_work(), which uses the net->*_stats variables,
> can be scheduled before they are initialized.
>
> Let's move _vdpa_register_device() to the end of vdpasim_net_dev_add()
> and add a comment to avoid future issues.
>
> Fixes: 0899774cb360 ("vdpa_sim_net: vendor satistics")
> Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
This is needed for -stable.
Thanks
> ---
>
> Notes:
> I don't have a reproducer, but I became aware of this problem while
> I was changing the buffer allocation.
>
> In the block device, as soon as the device is registered, the driver
> sends several requests, and I guess this might happen for the net
> device as well.
>
> Thanks,
> Stefano
>
> drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> index 862f405362de..dfe2ce341803 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> @@ -466,16 +466,21 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
>
> vdpasim_net_setup_config(simdev, config);
>
> - ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
> - if (ret)
> - goto reg_err;
> -
> net = sim_to_net(simdev);
>
> u64_stats_init(&net->tx_stats.syncp);
> u64_stats_init(&net->rx_stats.syncp);
> u64_stats_init(&net->cq_stats.syncp);
>
> + /*
> + * Initialization must be completed before this call, since it can
> + * connect the device to the vDPA bus, so requests can arrive after
> + * this call.
> + */
> + ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
> + if (ret)
> + goto reg_err;
> +
> return 0;
>
> reg_err:
> --
> 2.39.2
>
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