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Date:   Tue, 1 Mar 2022 09:05:38 +0100
From:   Stefano Garzarella <sgarzare@redhat.com>
To:     Yi Wang <wang.yi59@zte.com.cn>
Cc:     Michael Tsirkin <mst@redhat.com>, Jason Wang <jasowang@redhat.com>,
        Eli Cohen <elic@nvidia.com>,
        Xie Yongji <xieyongji@bytedance.com>,
        Wu Zongyong <wuzongyong@linux.alibaba.com>,
        Linux Virtualization <virtualization@lists.linux-foundation.org>,
        kernel list <linux-kernel@vger.kernel.org>,
        xue.zhihong@zte.com.cn, Yi Wang <wang.yi59@zte.com.cn>,
        wang.liang82@zte.com.cn, Zhang Min <zhang.min9@zte.com.cn>
Subject: Re: [PATCH] vdpa: fix use-after-free on vp_vdpa_remove
Message-ID: <CAGxU2F5-PUzDNQrMiOn4Naj7Mga3NZ4kb6AHi7AfPSVauhGFTw@mail.gmail.com>
References: <20220301091059.46869-1-wang.yi59@zte.com.cn>
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On Tue, Mar 1, 2022 at 2:26 AM Yi Wang <wang.yi59@zte.com.cn> wrote:
>
> From: Zhang Min <zhang.min9@zte.com.cn>
>
> When vp_vdpa driver is unbind, vp_vdpa is freed in vdpa_unregister_device
> and then vp_vdpa->mdev.pci_dev is dereferenced in vp_modern_remove,
> triggering use-after-free.
>
> Call Trace of unbinding driver free vp_vdpa :
> do_syscall_64
>   vfs_write
>     kernfs_fop_write_iter
>       device_release_driver_internal
>         pci_device_remove
>           vp_vdpa_remove
>             vdpa_unregister_device
>               kobject_release
>                 device_release
>                   kfree
>
> Call Trace of dereference vp_vdpa->mdev.pci_dev:
> vp_modern_remove
>   pci_release_selected_regions
>     pci_release_region
>       pci_resource_len
>         pci_resource_end
>           (dev)->resource[(bar)].end

We can add the fixes tag:

Fixes: 64b9f64f80a6 ("vdpa: introduce virtio pci driver")

>
> Signed-off-by: Zhang Min <zhang.min9@zte.com.cn>
> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
> ---
>  drivers/vdpa/virtio_pci/vp_vdpa.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index a57e381e830b..cce101e6a940 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -533,8 +533,8 @@ static void vp_vdpa_remove(struct pci_dev *pdev)
>  {
>         struct vp_vdpa *vp_vdpa = pci_get_drvdata(pdev);
>
> -       vdpa_unregister_device(&vp_vdpa->vdpa);
>         vp_modern_remove(&vp_vdpa->mdev);
> +       vdpa_unregister_device(&vp_vdpa->vdpa);
>  }
>
>  static struct pci_driver vp_vdpa_driver = {
> --
> 2.27.0
>

The patch LGTM:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>