Re: [PATCH v2] vsock/hv_sock: don't finish a connection on a socket being released

hvs_open_connection() only checks sk->sk_state (TCP_LISTEN for a
host-initiated connection, TCP_SYN_SENT for a guest-initiated one) before
proceeding. __vsock_release() sets sk->sk_shutdown = SHUTDOWN_MASK and, for
a listener, flushes the accept queue, while leaving sk_state unchanged. A
VMBUS channel offer that races close() therefore still passes the state
check and either enqueues a child onto the already-flushed accept queue
(conn_from_host) or completes a connection on a socket being torn down
(!conn_from_host); the socket and its VMBUS channel then leak.

The virtio transport guards the listener case in
virtio_transport_recv_listen(); hv_sock has no equivalent. Add a
sk_shutdown == SHUTDOWN_MASK check to the common path right after
lock_sock(), so both the host- and guest-initiated paths bail out.
hv_sock holds lock_sock(sk) across hvs_open_connection(), so the check is
race-free.

This was found by code inspection; I do not have Hyper-V hardware to test on.

Fixes: ae0078fcf0a5 ("hv_sock: implements Hyper-V transport for Virtual Sockets (AF_VSOCK)")
Signed-off-by: Bartłomiej Dmitruk <redacted>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260919123128.28868-1-bartlomiej.dmitruk@isec.pl?part=1