On Wed, 9 Jul 2025 at 17:26, Stefano Garzarella <sgarz...@redhat.com> wrote: > > On Wed, 9 Jul 2025 at 16:54, Konstantin Shkolnyy <k...@linux.ibm.com> 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.
Just to be clear, I was seeing something a bit different. The accept() in the server is no-blocking, since we set O_NONBLOCK on the socket, so I see the server looping around a failing accept() (errno == EAGAIN) while dequeueing the CONTROL_CONTINUE messages, so after 10/15 seconds the server ends on my case. It seems strange that in your case it blocks, since it should be a no-blocking call. Stefano > > > > 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-sgarz...@redhat.com/ > > Please, send a T-b/R-b on that if you can. > > Stefano
