On 1/13/25 16:01, Stefano Garzarella wrote:

On Mon, Jan 13, 2025 at 02:51:58PM +0100, Michal Luczaj wrote:

quoted

On 1/13/25 12:05, Stefano Garzarella wrote:

quoted

...
An alternative approach, which would perhaps allow us to avoid all this,
is to re-insert the socket in the unbound list after calling release()
when we deassign the transport.

WDYT?

If we can't keep the old state (sk_state, transport, etc) on failed
re-connect() then reverting back to initial state sounds, uhh, like an
option :) I'm not sure how well this aligns with (user's expectations of)
good ol' socket API, but maybe that train has already left.

We really want to behave as similar as possible with the other sockets,
like AF_INET, so I would try to continue toward that train.

I was worried that such connect()/transport error handling may have some
user visible side effects, but I guess I was wrong. I mean you can still
reach a sk_state=TCP_LISTEN with a transport assigned[1], but perhaps
that's a different issue.

I've tried your suggestion on top of this series. Passes the tests.

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index fa9d1b49599b..4718fe86689d 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c

@@ -492,6 +492,10 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 		vsk->transport->release(vsk);
 		vsock_deassign_transport(vsk);
 
+		vsock_addr_unbind(&vsk->local_addr);
+		vsock_addr_unbind(&vsk->remote_addr);
+		vsock_insert_unbound(vsk);
+
 		/* transport's release() and destruct() can touch some socket
 		 * state, since we are reassigning the socket to a new transport
 		 * during vsock_connect(), let's reset these fields to have a

quoted

Another possibility would be to simply brick the socket on failed (re)connect.

I see, though, this is not the behavior of AF_INET for example, right?

Right.

Do you have time to investigate/fix this problem?
If not, I'll try to look into it in the next few days, maybe next week.

I'm happy to help, but it's not like I have any better ideas.

Michal

[1]: E.g. this way:

from socket import *

MAX_PORT_RETRIES = 24 # net/vmw_vsock/af_vsock.c
VMADDR_CID_LOCAL = 1
VMADDR_PORT_ANY = -1
hold = []

def take_port(port):
	s = socket(AF_VSOCK, SOCK_SEQPACKET)
	s.bind((VMADDR_CID_LOCAL, port))
	hold.append(s)
	return s

s = take_port(VMADDR_PORT_ANY)
_, port = s.getsockname()
for _ in range(MAX_PORT_RETRIES):
	port += 1
	take_port(port);

s = socket(AF_VSOCK, SOCK_SEQPACKET)
err = s.connect_ex((VMADDR_CID_LOCAL, port))
assert err != 0
print("ok, connect failed; transport set")

s.bind((VMADDR_CID_LOCAL, port+1))
s.listen(16)