On Wed Jul 22, 2026 at 2:47 AM EDT, Jiayuan Chen wrote: > Several CI runs failed in the libarena parallel tests with -4 (-EINTR) [1], > which says nothing about what actually went wrong. > > Two workers can fail like this: > > worker 1: gives up, e.g. the rendezvous times out, sets test_abort and > returns its own error (-ETIMEDOUT) > worker 2: sees test_abort and returns -EINTR > > -EINTR only means "someone else already gave up", so it carries no > information. Which of the two gets reported depends on the order > pthread_join() collects them, because > > err = err ?: (long)thread_ret; > > keeps the first non-zero value and drops the rest. When the -EINTR worker > comes first, the error describing the actual failure is lost. > > Let any other error win over -EINTR, and log each worker that returned an > error. > > It is still unclear whether the timeouts come from CI load or from a > problem in the test itself. Report the error accurately first, so the next > failure can be diagnosed. > > [1]: > https://github.com/kernel-patches/bpf/actions/runs/29867905253/job/88764463566 > https://github.com/kernel-patches/bpf/actions/runs/29878191901/job/88794845824
Overall change makes sense, a couple things. I'll also look into the error itself. > > Signed-off-by: Jiayuan Chen <[email protected]> > --- > .../testing/selftests/bpf/prog_tests/libarena.c | 17 ++++++++++++++++- > 1 file changed, 16 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/libarena.c > b/tools/testing/selftests/bpf/prog_tests/libarena.c > index df7e4b8dc394..65743920ff69 100644 > --- a/tools/testing/selftests/bpf/prog_tests/libarena.c > +++ b/tools/testing/selftests/bpf/prog_tests/libarena.c > @@ -112,13 +112,28 @@ static int run_libarena_parallel_test_workers(struct > libarena *skel, > > > for (i = 0; i < nthreads; i++) { > + int worker_err; > + Let's hoist this definition up to the top of the function. > ret = pthread_join(threads[i], &thread_ret); > if (!ASSERT_OK(ret, "pthread_join")) { > err = err ?: ret; > continue; > } > > - err = err ?: (long)thread_ret; > + worker_err = (long)thread_ret; > + if (!worker_err) > + continue; > + If we are ignoring -EINTR errors from workers then let's skip the printing for them altogether, otherwise below we keep printing the "main" error for every interrupted thread. > + /* > + * A worker that bails out because another one already gave up > + * reports -EINTR. That is collateral damage, so let any other > + * error win: it tells us what actually went wrong. Capitalize "it" > + */ > + if (!err || err == -EINTR) > + err = worker_err; > + > + fprintf(stdout, "%.*s__%d returned %d\n", (int)prefixlen, name, > + i, worker_err); > } > > free(threads);
