Re: [PATCH v3 1/3] kasan: switch kunit tests to console tracepoints

[Marco Elver <elver@google.com>]

On Tue, 14 Feb 2023 at 02:21, Peter Collingbourne <pcc@google.com> wrote:
>
> On Tue, Oct 18, 2022 at 10:17 AM <andrey.konovalov@linux.dev> wrote:
> >
> > From: Andrey Konovalov <andreyknvl@google.com>
> >
> > Switch KUnit-compatible KASAN tests from using per-task KUnit resources
> > to console tracepoints.
> >
> > This allows for two things:
> >
> > 1. Migrating tests that trigger a KASAN report in the context of a task
> >    other than current to KUnit framework.
> >    This is implemented in the patches that follow.
> >
> > 2. Parsing and matching the contents of KASAN reports.
> >    This is not yet implemented.
> >
> > Reviewed-by: Marco Elver <elver@google.com>
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> >
> > ---
> >
> > Changed v2->v3:
> > - Rebased onto 6.1-rc1
> >
> > Changes v1->v2:
> > - Remove kunit_kasan_status struct definition.
> > ---
> >  lib/Kconfig.kasan     |  2 +-
> >  mm/kasan/kasan.h      |  8 ----
> >  mm/kasan/kasan_test.c | 85 +++++++++++++++++++++++++++++++------------
> >  mm/kasan/report.c     | 31 ----------------
> >  4 files changed, 63 insertions(+), 63 deletions(-)
> >
> > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> > index ca09b1cf8ee9..ba5b27962c34 100644
> > --- a/lib/Kconfig.kasan
> > +++ b/lib/Kconfig.kasan
> > @@ -181,7 +181,7 @@ config KASAN_VMALLOC
> >
> >  config KASAN_KUNIT_TEST
> >         tristate "KUnit-compatible tests of KASAN bug detection capabilities" if !KUNIT_ALL_TESTS
> > -       depends on KASAN && KUNIT
> > +       depends on KASAN && KUNIT && TRACEPOINTS
>
> My build script for a KASAN-enabled kernel does something like:
>
> make defconfig
> scripts/config -e CONFIG_KUNIT -e CONFIG_KASAN -e CONFIG_KASAN_HW_TAGS
> -e CONFIG_KASAN_KUNIT_TEST
> yes '' | make syncconfig
>
> and after this change, the unit tests are no longer built. Should this
> use "select TRACING" instead?

I think we shouldn't select TRACING, which should only be selected by
tracers. You'd need CONFIG_FTRACE=y.

Since FTRACE is rather big, we probably also shouldn't implicitly
select it. Instead, at least when using kunit.py tool, we could add a
mm/kasan/.kunitconfig like:

CONFIG_KUNIT=y
CONFIG_KASAN=y
CONFIG_KASAN_KUNIT_TEST=y
# Additional dependencies.
CONFIG_FTRACE=y

Which mirrors the KFENCE mm/kfence/.kunitconfig. But that doesn't help
if you want to run it with something other than KUnit tool.