On Wed, 2025-07-23 at 09:42 -0700, Yonghong Song wrote:
>
>
> On 7/22/25 8:34 AM, KaFai Wan wrote:
> > The result:
> >
> > $ tools/testing/selftests/bpf/test_progs -t
> > tracing_failure/tracing_deny
> > #468/3 tracing_failure/tracing_deny:OK
> > #468 tracing_failure:OK
> > Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED
> >
> > Signed-off-by: KaFai Wan <kafai....@linux.dev>
>
> LGTM but see a nit below.
>
> Acked-by: Yonghong Song <yonghong.s...@linux.dev>
>
> > ---
> > .../bpf/prog_tests/tracing_failure.c | 33
> > +++++++++++++++++++
> > .../selftests/bpf/progs/tracing_failure.c | 6 ++++
> > 2 files changed, 39 insertions(+)
> >
> > diff --git
> > a/tools/testing/selftests/bpf/prog_tests/tracing_failure.c
> > b/tools/testing/selftests/bpf/prog_tests/tracing_failure.c
> > index a222df765bc3..140fb0d175cf 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/tracing_failure.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/tracing_failure.c
> > @@ -28,10 +28,43 @@ static void test_bpf_spin_lock(bool
> > is_spin_lock)
> > tracing_failure__destroy(skel);
> > }
> >
> > +static void test_tracing_deny(void)
> > +{
> > + struct tracing_failure *skel;
> > + char log_buf[256];
> > + int btf_id, err;
> > +
> > + /* migrate_disable depends on CONFIG_SMP */
> > + btf_id = libbpf_find_vmlinux_btf_id("migrate_disable",
> > BPF_TRACE_FENTRY);
> > + if (btf_id <= 0) {
> > + test__skip();
> > + return;
> > + }
>
> There is a discussion about inlining migrate_disable(). See
>
> https://lore.kernel.org/bpf/CAADnVQ+Afov4E=9t=3M=zZmO9z4ZqT6imWD5xijDHshTf3J=r...@mail.gmail.com/
>
> Maybe trying to find a different function? Otherwise, if
> migrate_disable
> is inlined and this test will become useless.
>
Okey, I will use __rcu_read_lock() instead.
> > +
> > + skel = tracing_failure__open();
> > + if (!ASSERT_OK_PTR(skel, "tracing_failure__open"))
> > + return;
> > +
> > + bpf_program__set_autoload(skel->progs.tracing_deny, true);
> > + bpf_program__set_log_buf(skel->progs.tracing_deny,
> > log_buf, sizeof(log_buf));
> > +
> > + err = tracing_failure__load(skel);
> > + if (!ASSERT_ERR(err, "tracing_failure__load"))
> > + goto out;
> > +
> > + ASSERT_HAS_SUBSTR(log_buf,
> > + "Attaching tracing programs to function
> > 'migrate_disable' is rejected.",
> > + "log_buf");
> > +out:
> > + tracing_failure__destroy(skel);
> > +}
> > +
> > void test_tracing_failure(void)
> > {
> > if (test__start_subtest("bpf_spin_lock"))
> > test_bpf_spin_lock(true);
> > if (test__start_subtest("bpf_spin_unlock"))
> > test_bpf_spin_lock(false);
> > + if (test__start_subtest("tracing_deny"))
> > + test_tracing_deny();
> > }
> > diff --git a/tools/testing/selftests/bpf/progs/tracing_failure.c
> > b/tools/testing/selftests/bpf/progs/tracing_failure.c
> > index d41665d2ec8c..dfa152e8194e 100644
> > --- a/tools/testing/selftests/bpf/progs/tracing_failure.c
> > +++ b/tools/testing/selftests/bpf/progs/tracing_failure.c
> > @@ -18,3 +18,9 @@ int BPF_PROG(test_spin_unlock, struct
> > bpf_spin_lock *lock)
> > {
> > return 0;
> > }
> > +
> > +SEC("?fentry/migrate_disable")
> > +int BPF_PROG(tracing_deny)
> > +{
> > + return 0;
> > +}
>
--
Thanks,
KaFai
