Re: [PATCH net v2 3/5] vsock: Enforce no-transport invariant for TCP_LISTEN sockets
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From: Stefano Garzarella <sgarzare@redhat.com>
Date: 2026-09-16 12:30:47
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kvm, lkml, netdev
On Tue, Sep 15, 2026 at 03:15:14PM +0200, Michal Luczaj wrote:
A non-blocking connect() running in parallel with a blocking connect(), combined with a racy listen() that hits right after a connect timeout: TCP_SYN_SENT -> TCP_CLOSE -> TCP_LISTEN, while the connect() loop is still in progress. Enforce the invariant. Prevent a socket from becoming a listener after acquiring a transport.
We should improve this comment; it's not entirely clear to me, TBH.
quoted hunk ↗ jump to hunk
Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Signed-off-by: Michal Luczaj <redacted> --- net/vmw_vsock/af_vsock.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index f840498b58af..499e902becfa 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c@@ -1973,13 +1973,13 @@ static int vsock_listen(struct socket *sock, int backlog)goto out; } - if (sock->state != SS_UNCONNECTED) { + vsk = vsock_sk(sk); + + if (sock->state != SS_UNCONNECTED || vsk->transport) {
Are we changing the behavior when an error occurs? If we call `connect()` on a socket (with no others running in parallel), it fails, and then when we call `listen()`, it now fails, whereas before it didn't. Can this happen? Is that what we want? If so, we should mention it at least in the commit description; if not, perhaps we should unassign the transport in the `connect` call. Thanks, Stefano
err = -EINVAL;
goto out;
}
- vsk = vsock_sk(sk);
-
if (!vsock_addr_bound(&vsk->local_addr)) {
err = -EINVAL;
goto out;
--
2.55.0