On Thu, 2023-08-31 at 09:31 +0800, Xu Kuohai wrote:
> From: Xu Kuohai <xukuohai@xxxxxxxxxx>
>
> While commit 90f0074cd9f9 ("selftests/bpf: fix a CI failure caused by vsock sockmap test")
> fixes a receive failure of vsock sockmap test, there is still a write failure:
>
> Error: #211/79 sockmap_listen/sockmap VSOCK test_vsock_redir
> Error: #211/79 sockmap_listen/sockmap VSOCK test_vsock_redir
> ./test_progs:vsock_unix_redir_connectible:1501: egress: write: Transport endpoint is not connected
> vsock_unix_redir_connectible:FAIL:1501
> ./test_progs:vsock_unix_redir_connectible:1501: ingress: write: Transport endpoint is not connected
> vsock_unix_redir_connectible:FAIL:1501
> ./test_progs:vsock_unix_redir_connectible:1501: egress: write: Transport endpoint is not connected
> vsock_unix_redir_connectible:FAIL:1501
>
> The reason is that the vsock connection in the test is set to ESTABLISHED state
> by function virtio_transport_recv_pkt, which is executed in a workqueue thread,
> so when the user space test thread runs before the workqueue thread, this
> problem occurs.
>
> To fix it, before writing the connection, wait for it to be connected.
Fun fact:
while trying this patch I hit an oops [1]. I'm currently trying to
bisect the commit causing this oops and have the following observation:
- good revisions don't have this test as flip-flop
- bad revisions have this test as flip-flop.
[1] https://lore.kernel.org/bpf/de816b89073544deb2ce34c4b242d583a6d4660f.camel@xxxxxxxxx/
>
> Fixes: d61bd8c1fd02 ("selftests/bpf: add a test case for vsock sockmap")
> Signed-off-by: Xu Kuohai <xukuohai@xxxxxxxxxx>
> ---
> .../bpf/prog_tests/sockmap_helpers.h | 29 +++++++++++++++++++
> .../selftests/bpf/prog_tests/sockmap_listen.c | 5 ++++
> 2 files changed, 34 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> index d12665490a90..837dfb0361c6 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> @@ -179,6 +179,35 @@
> __ret; \
> })
>
> +static inline int poll_connect(int fd, unsigned int timeout_sec)
> +{
> + struct timeval timeout = { .tv_sec = timeout_sec };
> + fd_set wfds;
> + int r;
> + int eval;
> + socklen_t esize;
> +
> + FD_ZERO(&wfds);
> + FD_SET(fd, &wfds);
> +
> + r = select(fd + 1, NULL, &wfds, NULL, &timeout);
> + if (r == 0)
> + errno = ETIME;
> +
> + if (r != 1)
> + return -1;
> +
> + if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &eval, &esize) < 0)
> + return -1;
> +
> + if (eval != 0) {
> + errno = eval;
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> static inline int poll_read(int fd, unsigned int timeout_sec)
> {
> struct timeval timeout = { .tv_sec = timeout_sec };
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> index 5674a9d0cacf..2d3bf38677b6 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> @@ -1452,6 +1452,11 @@ static int vsock_socketpair_connectible(int sotype, int *v0, int *v1)
> if (p < 0)
> goto close_cli;
>
> + if (poll_connect(c, IO_TIMEOUT_SEC) < 0) {
> + FAIL_ERRNO("poll_connect");
> + goto close_cli;
> + }
> +
> *v0 = p;
> *v1 = c;
>
