vhost/vsock: don't check owner in vhost_vsock_stop() while releasing

stable inclusion
from stable-v5.10.103
commit 698dc7d13c4e972214458996455447651a657264
bugzilla: https://gitee.com/openeuler/kernel/issues/I56NE7

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=698dc7d13c4e972214458996455447651a657264



--------------------------------

commit a58da53f upstream.

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.

When invoked from release we can not fail so we don't check return
code of vhost_vsock_stop(). We need to stop vsock even if it's not
the owner.

Fixes: 433fc58e ("VSOCK: Introduce vhost_vsock.ko")
Cc: stable@vger.kernel.org
Reported-by:  <syzbot+1e3ea63db39f2b4440e0@syzkaller.appspotmail.com>
Reported-and-tested-by:  <syzbot+3140b17cb44a7b174008@syzkaller.appspotmail.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>