From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Garzarella Subject: [RFC PATCH 12/13] vsock: prevent transport modules unloading Date: Fri, 27 Sep 2019 13:27:02 +0200 Message-ID: <20190927112703.17745-13-sgarzare__31283.0815719039$1569583776$gmane$org@redhat.com> References: <20190927112703.17745-1-sgarzare@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190927112703.17745-1-sgarzare@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: netdev@vger.kernel.org Cc: Sasha Levin , linux-hyperv@vger.kernel.org, Stephen Hemminger , kvm@vger.kernel.org, "Michael S. Tsirkin" , Dexuan Cui , Haiyang Zhang , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Stefan Hajnoczi , "David S. Miller" , Jorgen Hansen List-Id: virtualization@lists.linuxfoundation.org This patch adds 'module' member in the 'struct vsock_transport' in order to get/put the transport module. This prevents the module unloading while sockets are assigned to it. We increase the module refcnt when a socket is assigned to a transport, and we decrease the module refcnt when the socket is destructed. Signed-off-by: Stefano Garzarella --- drivers/vhost/vsock.c | 1 + include/net/af_vsock.h | 1 + net/vmw_vsock/af_vsock.c | 23 +++++++++++++++++------ net/vmw_vsock/hyperv_transport.c | 1 + net/vmw_vsock/virtio_transport.c | 1 + net/vmw_vsock/vmci_transport.c | 1 + 6 files changed, 22 insertions(+), 6 deletions(-) diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 375af01a5b64..6d7a8fc9eb63 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -387,6 +387,7 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock) static struct virtio_transport vhost_transport = { .transport = { .features = VSOCK_TRANSPORT_F_H2G, + .module = THIS_MODULE, .get_local_cid = vhost_transport_get_local_cid, diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h index 2a081d19e20d..f10fa918bf23 100644 --- a/include/net/af_vsock.h +++ b/include/net/af_vsock.h @@ -100,6 +100,7 @@ struct vsock_transport_send_notify_data { struct vsock_transport { uint64_t features; + struct module *module; /* Initialize/tear-down socket. */ int (*init)(struct vsock_sock *, struct vsock_sock *); diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index c5f46b8242ce..750b62711b01 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -416,13 +416,28 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) return -ESOCKTNOSUPPORT; } - if (!vsk->transport) + /* We increase the module refcnt to prevent the tranport unloading + * while there are open sockets assigned to it. + */ + if (!vsk->transport || !try_module_get(vsk->transport->module)) { + vsk->transport = NULL; return -ENODEV; + } return vsk->transport->init(vsk, psk); } EXPORT_SYMBOL_GPL(vsock_assign_transport); +static void vsock_deassign_transport(struct vsock_sock *vsk) +{ + if (!vsk->transport) + return; + + vsk->transport->destruct(vsk); + module_put(vsk->transport->module); + vsk->transport = NULL; +} + static bool vsock_find_cid(unsigned int cid) { if (transport_g2h && cid == transport_g2h->get_local_cid()) @@ -728,8 +743,7 @@ static void vsock_sk_destruct(struct sock *sk) { struct vsock_sock *vsk = vsock_sk(sk); - if (vsk->transport) - vsk->transport->destruct(vsk); + vsock_deassign_transport(vsk); /* When clearing these addresses, there's no need to set the family and * possibly register the address family with the kernel. @@ -2161,9 +2175,6 @@ void vsock_core_unregister(const struct vsock_transport *t) { mutex_lock(&vsock_register_mutex); - /* RFC-TODO: maybe we should check if there are open sockets - * assigned to that transport and avoid the unregistration - */ if (transport_h2g == t) transport_h2g = NULL; diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c index 94e6fc905a77..bd4f3c222904 100644 --- a/net/vmw_vsock/hyperv_transport.c +++ b/net/vmw_vsock/hyperv_transport.c @@ -857,6 +857,7 @@ int hvs_notify_send_post_enqueue(struct vsock_sock *vsk, ssize_t written, static struct vsock_transport hvs_transport = { .features = VSOCK_TRANSPORT_F_G2H, + .module = THIS_MODULE, .get_local_cid = hvs_get_local_cid, diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index 0ff037ef7f8e..439fe01e6691 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -463,6 +463,7 @@ static void virtio_vsock_rx_done(struct virtqueue *vq) static struct virtio_transport virtio_transport = { .transport = { .features = VSOCK_TRANSPORT_F_G2H, + .module = THIS_MODULE, .get_local_cid = virtio_transport_get_local_cid, diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c index 52e63952d0d4..900392686c03 100644 --- a/net/vmw_vsock/vmci_transport.c +++ b/net/vmw_vsock/vmci_transport.c @@ -2021,6 +2021,7 @@ static u32 vmci_transport_get_local_cid(void) static struct vsock_transport vmci_transport = { .features = VSOCK_TRANSPORT_F_DGRAM | VSOCK_TRANSPORT_F_H2G, + .module = THIS_MODULE, .init = vmci_transport_socket_init, .destruct = vmci_transport_destruct, .release = vmci_transport_release, -- 2.21.0