Re: [PATCH v2 3/3] selftest/bpf: Test a perf bpf program that suppresses side effects.

[Kyle Huey]

On Thu, Dec 7, 2023 at 11:20 AM Marco Elver <elver@xxxxxxxxxx> wrote:
>
> On Thu, 7 Dec 2023 at 20:12, Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote:
> >
> > On Thu, Dec 7, 2023 at 8:35 AM Kyle Huey <me@xxxxxxxxxxxx> wrote:
> > >
> > > The test sets a hardware breakpoint and uses a bpf program to suppress the
> > > side effects of a perf event sample, including I/O availability signals,
> > > SIGTRAPs, and decrementing the event counter limit, if the ip matches the
> > > expected value. Then the function with the breakpoint is executed multiple
> > > times to test that all effects behave as expected.
> > >
> > > Signed-off-by: Kyle Huey <khuey@xxxxxxxxxxxx>
> > > ---
> > >  .../selftests/bpf/prog_tests/perf_skip.c      | 145 ++++++++++++++++++
> > >  .../selftests/bpf/progs/test_perf_skip.c      |  15 ++
> > >  2 files changed, 160 insertions(+)
> > >  create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c
> > >  create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c
> > >
> > > diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c
> > > new file mode 100644
> > > index 000000000000..f6fa9bfd9efa
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c
> > > @@ -0,0 +1,145 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +#define _GNU_SOURCE
> > > +
> > > +/* We need the latest siginfo from the kernel repo. */
> > > +#include <asm/siginfo.h>
> >
> > selftests are built with UAPI headers' copies under tools/include, so
> > CI did catch a real issue, I think. Try copying
> > include/uapi/asm-generic/siginfo.h into
> > tools/include/uapi/asm-generic/siginfo.h ?
>
> I believe parts of this were inspired by
> tools/testing/selftests/perf_events/sigtrap_threads.c - getting the
> kernel headers is allowed, as long as $(KHDR_INCLUDES) is added to
> CFLAGS. See tools/testing/selftests/perf_events/Makefile. Not sure
> it's appropriate for this test though, if you don't want to add
> KHDR_INCLUDES for everything.

Yes, that's right. Namhyung's commit message for 91c97b36bd69 leads me
to believe that I should copy siginfo.h over into tools/include and
fix the perf_events self tests too.

- Kyle