On Tue, 22 Oct 2024 14:59:19 +0200 Laurent Vivier <lvivier(a)redhat.com> wrote:On 17/10/2024 02:10, Stefano Brivio wrote:I guess the connection from the first test is not closed properly, so it's still in TIME_WAIT or similar. Given the topic, I can imagine that something goes wrong as we check: if (ack && conn->events & TAP_FIN_SENT && conn->seq_ack_from_tap == conn->seq_to_tap) conn_event(c, conn, TAP_FIN_ACKED); in tcp_data_from_tap(). Or something around FIN segments anyway. You can give socat the 'reuseaddr' option, say: socat -u TCP4-LISTEN:10001,reuseaddr OPEN:test_big.bin,create,trunc to see if that's actually the case.On Wed, 16 Oct 2024 11:41:34 +1100 David Gibson <david(a)gibson.dropbear.id.au> wrote:I have a fix for that but there is an error I don't understand: when I run twice the test, the second time I have: guest: # socat -u TCP4-LISTEN:10001 OPEN:test_big.bin,create,trunc # socat -u TCP4-LISTEN:10001 OPEN:test_big.bin,create,trunc 2024/10/22 08:51:58 socat[1485] E bind(5, {AF=2 0.0.0.0:10001}, 16): Address already in use host: $ socat -u OPEN:test/big.bin TCP4:127.0.0.1:10001 If I wait a little it can work again several times and fails again. Any idea?On Tue, Oct 15, 2024 at 09:54:38PM +0200, Stefano Brivio wrote:I tested it again just to be sure on a recent net.git kernel: sometimes the first test in passt_vu_in_ns/tcp, "TCP/IPv4: host to guest: big transfer" hangs on my setup, sometimes it's the "TCP/IPv4: ns to guest (using loopback address): big transfer" test instead. I can reproduce at least one of the two issues consistently (tests stopped 5 times out of 5). The socat client completes the transfer, the server is still waiting for something. I haven't taken captures yet or tried to re-send from the client. It all works (consistently) with an older kernel without support for SO_PEEK_OFF on TCP, but also on this kernel if I force peek_offset_cap to false in tcp_init().[Still partial review][snip]> + if (peek_offset_cap) > + already_sent = 0; > + > + iov_vu[0].iov_base = tcp_buf_discard; > + iov_vu[0].iov_len = already_sent; I think I had a similar comment to a previous revision. Now, I haven't tested this (yet) on a kernel with support for SO_PEEK_OFF on TCP, but I think this should eventually follow the same logic as the (updated) tcp_buf_data_from_sock(): we should use tcp_buf_discard only if (!peek_offset_cap). It's fine to always initialise VIRTQUEUE_MAX_SIZE iov_vu items, starting from 1, for simplicity. But I'm not sure if it's safe to pass a zero iov_len if (peek_offset_cap).I'll test that (unless you already did) -- if it works, we can fix this up later as well.I believe I tested it at some point, and I think we're already using it somewhere.The patch is: [...]I can try that in a bit. From --debug (or --trace) output the issue might be obvious, by the way (you can enable that in the test suite with DEBUG=1). I guess you'll see FIN from one side and not from the other one. -- Stefano