Re: [PATCH 1/2] vsock: each transport cycles only on its own sockets

[Michael S. Tsirkin]

On Thu, Mar 10, 2022 at 07:53:25AM -0500, Michael S. Tsirkin wrote:
> This message had 
> In-Reply-To: <20220310124936.4179591-1-jiyong@xxxxxxxxxx>
> in its header but 20220310124936.4179591-2-jiyong@xxxxxxxxxx was
> not sent to the list.
> Please don't do that. Instead, please write and send a proper
> cover letter. Thanks!
> 


Also, pls version in subject e.g. PATCH v2, and include
full changelog in the cover letter. Thanks!

> On Thu, Mar 10, 2022 at 09:49:35PM +0900, Jiyong Park wrote:
> > When iterating over sockets using vsock_for_each_connected_socket, make
> > sure that a transport filters out sockets that don't belong to the
> > transport.
> > 
> > There actually was an issue caused by this; in a nested VM
> > configuration, destroying the nested VM (which often involves the
> > closing of /dev/vhost-vsock if there was h2g connections to the nested
> > VM) kills not only the h2g connections, but also all existing g2h
> > connections to the (outmost) host which are totally unrelated.
> > 
> > Tested: Executed the following steps on Cuttlefish (Android running on a
> > VM) [1]: (1) Enter into an `adb shell` session - to have a g2h
> > connection inside the VM, (2) open and then close /dev/vhost-vsock by
> > `exec 3< /dev/vhost-vsock && exec 3<&-`, (3) observe that the adb
> > session is not reset.
> > 
> > [1] https://android.googlesource.com/device/google/cuttlefish/
> > 
> > Fixes: c0cfa2d8a788 ("vsock: add multi-transports support")
> > Signed-off-by: Jiyong Park <jiyong@xxxxxxxxxx>
> > ---
> >  drivers/vhost/vsock.c            | 4 ++++
> >  net/vmw_vsock/virtio_transport.c | 7 +++++++
> >  net/vmw_vsock/vmci_transport.c   | 5 +++++
> >  3 files changed, 16 insertions(+)
> > 
> > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> > index 37f0b4274113..853ddac00d5b 100644
> > --- a/drivers/vhost/vsock.c
> > +++ b/drivers/vhost/vsock.c
> > @@ -722,6 +722,10 @@ static void vhost_vsock_reset_orphans(struct sock *sk)
> >  	 * executing.
> >  	 */
> >  
> > +	/* Only handle our own sockets */
> > +	if (vsk->transport != &vhost_transport.transport)
> > +		return;
> > +
> >  	/* If the peer is still valid, no need to reset connection */
> >  	if (vhost_vsock_get(vsk->remote_addr.svm_cid))
> >  		return;
> > diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> > index fb3302fff627..61b24eb31d4b 100644
> > --- a/net/vmw_vsock/virtio_transport.c
> > +++ b/net/vmw_vsock/virtio_transport.c
> > @@ -24,6 +24,7 @@
> >  static struct workqueue_struct *virtio_vsock_workqueue;
> >  static struct virtio_vsock __rcu *the_virtio_vsock;
> >  static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
> > +static struct virtio_transport virtio_transport; /* forward declaration */
> >  
> >  struct virtio_vsock {
> >  	struct virtio_device *vdev;
> > @@ -357,11 +358,17 @@ static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
> >  
> >  static void virtio_vsock_reset_sock(struct sock *sk)
> >  {
> > +	struct vsock_sock *vsk = vsock_sk(sk);
> > +
> >  	/* vmci_transport.c doesn't take sk_lock here either.  At least we're
> >  	 * under vsock_table_lock so the sock cannot disappear while we're
> >  	 * executing.
> >  	 */
> >  
> > +	/* Only handle our own sockets */
> > +	if (vsk->transport != &virtio_transport.transport)
> > +		return;
> > +
> >  	sk->sk_state = TCP_CLOSE;
> >  	sk->sk_err = ECONNRESET;
> >  	sk_error_report(sk);
> > diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
> > index 7aef34e32bdf..cd2f01513fae 100644
> > --- a/net/vmw_vsock/vmci_transport.c
> > +++ b/net/vmw_vsock/vmci_transport.c
> > @@ -803,6 +803,11 @@ static void vmci_transport_handle_detach(struct sock *sk)
> >  	struct vsock_sock *vsk;
> >  
> >  	vsk = vsock_sk(sk);
> > +
> > +	/* Only handle our own sockets */
> > +	if (vsk->transport != &vmci_transport)
> > +		return;
> > +
> >  	if (!vmci_handle_is_invalid(vmci_trans(vsk)->qp_handle)) {
> >  		sock_set_flag(sk, SOCK_DONE);
> >  
> > -- 
> > 2.35.1.723.g4982287a31-goog