[PATCH net-next v2 13/15] vsock: prevent transport modules unloading
From: Stefano Garzarella <sgarzare@redhat.com>
Date: 2019-11-14 09:59:21
Also in:
kvm, linux-hyperv, lkml
Subsystem:
hyper-v/azure core and drivers, networking [general], the rest, virtio and vhost vsock driver, virtio core, virtio host (vhost), vm sockets (af_vsock), vmware vsock vmci transport driver · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Stefan Hajnoczi, Stefano Garzarella, "Michael S. Tsirkin", Jason Wang, Bryan Tan, Vishnu Dasa
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. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Jorgen Hansen <redacted> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> --- drivers/vhost/vsock.c | 2 ++ include/net/af_vsock.h | 2 ++ net/vmw_vsock/af_vsock.c | 20 ++++++++++++++++---- net/vmw_vsock/hyperv_transport.c | 2 ++ net/vmw_vsock/virtio_transport.c | 2 ++ net/vmw_vsock/vmci_transport.c | 1 + 6 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index b235f4bbe8ea..fdda9ec625ad 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c@@ -386,6 +386,8 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock) static struct virtio_transport vhost_transport = { .transport = { + .module = THIS_MODULE, + .get_local_cid = vhost_transport_get_local_cid, .init = virtio_transport_do_socket_init,
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index cf5c3691251b..4206dc6d813f 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h@@ -100,6 +100,8 @@ struct vsock_transport_send_notify_data { #define VSOCK_TRANSPORT_F_DGRAM 0x00000004 struct vsock_transport { + struct module *module; + /* Initialize/tear-down socket. */ int (*init)(struct vsock_sock *, struct vsock_sock *); void (*destruct)(struct vsock_sock *);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 5357714b6104..5cb0ae42d916 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c@@ -380,6 +380,16 @@ void vsock_enqueue_accept(struct sock *listener, struct sock *connected) } EXPORT_SYMBOL_GPL(vsock_enqueue_accept); +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; +} + /* Assign a transport to a socket and call the .init transport callback. * * Note: for stream socket this must be called when vsk->remote_addr is set
@@ -418,10 +428,13 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) return 0; vsk->transport->release(vsk); - vsk->transport->destruct(vsk); + vsock_deassign_transport(vsk); } - if (!new_transport) + /* We increase the module refcnt to prevent the transport unloading + * while there are open sockets assigned to it. + */ + if (!new_transport || !try_module_get(new_transport->module)) return -ENODEV; vsk->transport = new_transport;
@@ -741,8 +754,7 @@ 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.
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 1c9e65d7d94d..3c7d07a99fc5 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c@@ -857,6 +857,8 @@ int hvs_notify_send_post_enqueue(struct vsock_sock *vsk, ssize_t written, } static struct vsock_transport hvs_transport = { + .module = THIS_MODULE, + .get_local_cid = hvs_get_local_cid, .init = hvs_sock_init,
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 83ad85050384..1458c5c8b64d 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c@@ -462,6 +462,8 @@ static void virtio_vsock_rx_done(struct virtqueue *vq) static struct virtio_transport virtio_transport = { .transport = { + .module = THIS_MODULE, + .get_local_cid = virtio_transport_get_local_cid, .init = virtio_transport_do_socket_init,
diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index d9c9c834ad6f..644d32e43d23 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c@@ -2020,6 +2020,7 @@ static u32 vmci_transport_get_local_cid(void) } static struct vsock_transport vmci_transport = { + .module = THIS_MODULE, .init = vmci_transport_socket_init, .destruct = vmci_transport_destruct, .release = vmci_transport_release,
--
2.21.0