On Wed, 9 Jul 2025 at 16:54, Konstantin Shkolnyy [off-list ref] wrote:

I'm seeing a problem on s390 with the new "SOCK_STREAM transport change
null-ptr-deref" test. Here is how it appears to happen:

test_stream_transport_change_client() spins for 2s and sends 70K+
CONTROL_CONTINUE messages to the "control" socket.

test_stream_transport_change_server() spins calling accept() because it
keeps receiving CONTROL_CONTINUE.

When the client exits, the server has received just under 1K of those
70K CONTROL_CONTINUE, so it calls accept() again but the client has
exited, so accept() never returns and the server never exits.

Yep, I saw exactly the same issue while testing a new test.
I already sent a fix:
https://lore.kernel.org/netdev/20250708111701.129585-1-sgarzare@redhat.com/ (local)

Please, send a T-b/R-b on that if you can.

Stefano