Re: [PATCH bpf-next v6 5/5] selftests/bpf: Add ksock test for async callback guard

On Wed, Aug 12, 2026 at 05:25:40PM +0000, [email protected] wrote:
> > diff --git a/tools/testing/selftests/bpf/prog_tests/ksock_wq.c b/tools/testing/selftests/bpf/prog_tests/ksock_wq.c
> > new file mode 100644
> > index 0000000000000..5b9c6cc303922
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/ksock_wq.c
> > @@ -0,0 +1,34 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright (c) 2026 Isovalent */
> > +
> > +#include <unistd.h>
> > +
> > +#include "test_progs.h"
> > +#include "ksock_wq.skel.h"
> > +
> > +void test_ksock_wq(void)
> > +{
> > +	LIBBPF_OPTS(bpf_test_run_opts, opts);
> > +	struct ksock_wq *skel;
> > +	int err;
> > +
> > +	skel = ksock_wq__open_and_load();
> > +	if (!ASSERT_OK_PTR(skel, "ksock_wq open and load"))
> > +		return;
> > +
> > +	err = bpf_prog_test_run_opts(
> > +		bpf_program__fd(skel->progs.ksock_wq_start), &opts);
> > +	if (!ASSERT_OK(err, "run ksock_wq_start"))
> > +		goto out;
> > +	if (!ASSERT_OK(opts.retval, "ksock_wq_start retval"))
> > +		goto out;
> > +
> > +	while (!__atomic_load_n(&skel->bss->callback_done, __ATOMIC_ACQUIRE))
> > +		usleep(1000);
> 
> What happens if the workqueue callback never runs or blocks? This loop is
> unbounded, so the test would hang forever rather than failing. test_progs
> has no per-test timeout, so a hang here would block the entire test run.
> 
> Adding an iteration cap (e.g. a bounded retry count followed by an ASSERT
> on callback_done) would turn a CI hang into a normal test failure. For
> comparison, prog_tests/wq.c uses a bounded usleep(50) before asserting.

Unsure how likely it is but it could be indeed improved in this way.

> 
> > +
> > +	ASSERT_EQ(skel->bss->create_err, -EOPNOTSUPP,
> > +		  "workqueue create rejected");
> > +
> > +out:
> > +	ksock_wq__destroy(skel);
> > +}
> 
> [ ... ]
> 
> 
> ---
> AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
> See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
> 
> CI run summary: https://github.com/kernel-patches/bpf/actions/runs/31618864886