selftests: net: cope with slow env in gro.sh test

JIRA: https://issues.redhat.com/browse/RHEL-31077
Upstream Status: net.git commit e58779f

commit e58779f
Author: Paolo Abeni <pabeni@redhat.com>
Date:   Mon Feb 12 10:39:41 2024 +0100

    selftests: net: cope with slow env in gro.sh test

    The gro self-tests sends the packets to be aggregated with
    multiple write operations.

    When running is slow environment, it's hard to guarantee that
    the GRO engine will wait for the last packet in an intended
    train.

    The above causes almost deterministic failures in our CI for
    the 'large' test-case.

    Address the issue explicitly ignoring failures for such case
    in slow environments (KSFT_MACHINE_SLOW==true).

    Fixes: 7d15750 ("selftests/net: GRO coalesce test")
    Reviewed-by: Willem de Bruijn <willemb@google.com>
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>
    Link: https://lore.kernel.org/r/97d3ba83f5a2bfeb36f6bc0fb76724eb3dafb608.1707729403.git.pabeni@redhat.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Hangbin Liu <haliu@redhat.com>

Author: Hangbin Liu

tools/testing/selftests/net/gro.sh

@@ -31,6 +31,11 @@ run_test() {
       1>>log.txt
     wait "${server_pid}"
     exit_code=$?
+    if [[ ${test} == "large" && -n "${KSFT_MACHINE_SLOW}" && \
+          ${exit_code} -ne 0 ]]; then
+        echo "Ignoring errors due to slow environment" 1>&2
+        exit_code=0
+    fi
     if [[ "${exit_code}" -eq 0 ]]; then
         break;
     fi