Re: [PATCH] vsock: initialize the_virtio_vsock before using VQs
From: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Date: 2023-10-19 00:12:45
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kvm, lkml
On 18/10/2023 19:32, Alexandru Matei wrote:
quoted hunk ↗ jump to hunk
Once VQs are filled with empty buffers and we kick the host, it can send connection requests. If 'the_virtio_vsock' is not initialized before, replies are silently dropped and do not reach the host. Fixes: 0deab087b16a ("vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock") Signed-off-by: Alexandru Matei <redacted> --- net/vmw_vsock/virtio_transport.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index e95df847176b..eae0867133f8 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c@@ -658,12 +658,13 @@ static int virtio_vsock_probe(struct virtio_device *vdev) vsock->seqpacket_allow = true; vdev->priv = vsock; + rcu_assign_pointer(the_virtio_vsock, vsock); ret = virtio_vsock_vqs_init(vsock); - if (ret < 0) + if (ret < 0) { + rcu_assign_pointer(the_virtio_vsock, NULL); goto out; - - rcu_assign_pointer(the_virtio_vsock, vsock); + } mutex_unlock(&the_virtio_vsock_mutex);
Looks like virtio_vsock_restore() needs the same changes. But virtio_vsock_vqs_init() can fail only in virtio_find_vqs(). Maybe it can be split into 2 functions to avoid second rcu_assign_pointer() in case of error?