Michael S. Tsirkin
2022-Mar-10 13:01 UTC
[PATCH 1/2] vsock: each transport cycles only on its own sockets
On Thu, Mar 10, 2022 at 09:54:24PM +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 at google.com> > --- > 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;We know this is incomplete though. So I think it's the wrong thing to do when you backport, too. If all you worry about is breaking a binary module interface, how about simply exporting a new function when you backport. Thus you will have downstream both: void vsock_for_each_connected_socket(void (*fn)(struct sock *sk)); void vsock_for_each_connected_socket_new(struct vsock_transport *transport, void (*fn)(struct sock *sk)); and then upstream we can squash these two patches. Hmm?> 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
Stefano Garzarella
2022-Mar-10 13:18 UTC
[PATCH 1/2] vsock: each transport cycles only on its own sockets
On Thu, Mar 10, 2022 at 08:01:53AM -0500, Michael S. Tsirkin wrote:>On Thu, Mar 10, 2022 at 09:54:24PM +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 at google.com> >> --- >> 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; > > >We know this is incomplete though. So I think it's the wrong thing to do >when you backport, too. If all you worry about is breaking a binary >module interface, how about simply exporting a new function when you >backport. Thus you will have downstream both: > >void vsock_for_each_connected_socket(void (*fn)(struct sock *sk)); > >void vsock_for_each_connected_socket_new(struct vsock_transport *transport, > void (*fn)(struct sock *sk)); > > >and then upstream we can squash these two patches. > >Hmm? >Yep, reading more of the kernel documentation [1] it seems that upstream we don't worry about this. I agree with Michael, it's better to just have the final patch upstream and downstream will be handled accordingly. This should make it easier upstream to backport into stable branches future patches that depend on this change. Thanks, Stefano [1] https://www.kernel.org/doc/Documentation/process/stable-api-nonsense.rst