linux-kernel - Re: [PATCH] vhost/vsock: don't check owner in vhost_vsock

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Date:   Mon, 21 Feb 2022 14:59:30 +0100
From:   Stefano Garzarella <sgarzare@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     kernel list <linux-kernel@...r.kernel.org>,
        Mike Christie <michael.christie@...cle.com>,
        Jason Wang <jasowang@...hat.com>,
        netdev <netdev@...r.kernel.org>,
        Linux Virtualization <virtualization@...ts.linux-foundation.org>,
        Stefan Hajnoczi <stefanha@...hat.com>,
        kvm <kvm@...r.kernel.org>, Hillf Danton <hdanton@...a.com>
Subject: Re: [PATCH] vhost/vsock: don't check owner in vhost_vsock_stop()
 while releasing

On Mon, Feb 21, 2022 at 12:49 PM Stefano Garzarella <sgarzare@...hat.com> wrote:
>
> vhost_vsock_stop() calls vhost_dev_check_owner() to check the device
> ownership. It expects current->mm to be valid.
>
> vhost_vsock_stop() is also called by vhost_vsock_dev_release() when
> the user has not done close(), so when we are in do_exit(). In this
> case current->mm is invalid and we're releasing the device, so we
> should clean it anyway.
>
> Let's check the owner only when vhost_vsock_stop() is called
> by an ioctl.
>
> Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko")
> Cc: stable@...r.kernel.org
> Reported-by: syzbot+1e3ea63db39f2b4440e0@...kaller.appspotmail.com
> Signed-off-by: Stefano Garzarella <sgarzare@...hat.com>
> ---
>  drivers/vhost/vsock.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)

Reported-and-tested-by: syzbot+0abd373e2e50d704db87@...kaller.appspotmail.com
Reported-and-tested-by: syzbot+3140b17cb44a7b174008@...kaller.appspotmail.com