On Wed, 7 May 2025 at 17:15, Konstantin Shkolnyy <k...@linux.ibm.com> wrote:
>
> These tests:
> "SOCK_STREAM ioctl(SIOCOUTQ) 0 unsent bytes"
> "SOCK_SEQPACKET ioctl(SIOCOUTQ) 0 unsent bytes"
> output: "Unexpected 'SIOCOUTQ' value, expected 0, got 64 (CLIENT)".
>
> They test that the SIOCOUTQ ioctl reports 0 unsent bytes after the data
> have been received by the other side. However, sometimes there is a delay
> in updating this "unsent bytes" counter, and the test fails even though
> the counter properly goes to 0 several milliseconds later.
>
> The delay occurs in the kernel because the used buffer notification
> callback virtio_vsock_tx_done(), called upon receipt of the data by the
> other side, doesn't update the counter itself. It delegates that to
> a kernel thread (via vsock->tx_work). Sometimes that thread is delayed
> more than the test expects.
>
> Change the test to poll SIOCOUTQ until it returns 0 or a timeout occurs.
>
> Signed-off-by: Konstantin Shkolnyy <k...@linux.ibm.com>
> ---
> Changes in v2:
> - Use timeout_check() to end polling, instead of counting iterations.
Why removing the sleep?
Thanks,
Stefano
>
> tools/testing/vsock/vsock_test.c | 28 ++++++++++++++++------------
> 1 file changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/tools/testing/vsock/vsock_test.c
> b/tools/testing/vsock/vsock_test.c
> index d0f6d253ac72..613551132a96 100644
> --- a/tools/testing/vsock/vsock_test.c
> +++ b/tools/testing/vsock/vsock_test.c
> @@ -1264,21 +1264,25 @@ static void test_unsent_bytes_client(const struct
> test_opts *opts, int type)
> send_buf(fd, buf, sizeof(buf), 0, sizeof(buf));
> control_expectln("RECEIVED");
>
> - ret = ioctl(fd, SIOCOUTQ, &sock_bytes_unsent);
> - if (ret < 0) {
> - if (errno == EOPNOTSUPP) {
> - fprintf(stderr, "Test skipped, SIOCOUTQ not
> supported.\n");
> - } else {
> + /* SIOCOUTQ isn't guaranteed to instantly track sent data. Even though
> + * the "RECEIVED" message means that the other side has received the
> + * data, there can be a delay in our kernel before updating the
> "unsent
> + * bytes" counter. Repeat SIOCOUTQ until it returns 0.
> + */
> + timeout_begin(TIMEOUT);
> + do {
> + ret = ioctl(fd, SIOCOUTQ, &sock_bytes_unsent);
> + if (ret < 0) {
> + if (errno == EOPNOTSUPP) {
> + fprintf(stderr, "Test skipped, SIOCOUTQ not
> supported.\n");
> + break;
> + }
> perror("ioctl");
> exit(EXIT_FAILURE);
> }
> - } else if (ret == 0 && sock_bytes_unsent != 0) {
> - fprintf(stderr,
> - "Unexpected 'SIOCOUTQ' value, expected 0, got %i\n",
> - sock_bytes_unsent);
> - exit(EXIT_FAILURE);
> - }
> -
> + timeout_check("SIOCOUTQ");
> + } while (sock_bytes_unsent != 0);
> + timeout_end();
> close(fd);
> }
>
> --
> 2.34.1
>
