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Date:   Mon, 11 Dec 2023 19:59:10 +0100
From:   Paul =?utf-8?Q?Heidekr=C3=BCger?= <paul.heidekrueger@tum.de>
To:     Andrey Konovalov <andreyknvl@gmail.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Peter Collingbourne <pcc@google.com>,
        Marco Elver <elver@google.com>, andrey.konovalov@linux.dev,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        kasan-dev@googlegroups.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        linux-trace-kernel@vger.kernel.org,
        Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH v3 1/3] kasan: switch kunit tests to console tracepoints
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Hi Andrey!

On 11.12.2023 18:50, Andrey Konovalov wrote:
> On Mon, Dec 11, 2023 at 5:37 PM Paul Heidekrüger
> <paul.heidekrueger@tum.de> wrote:
> >
> > Hi all!
> >
> > On 05.05.2023 09:58, Steven Rostedt wrote:
> > > On Mon, 1 May 2023 15:02:37 -0700
> > > Peter Collingbourne <pcc@google.com> wrote:
> > >
> > > > > > "ftrace" is really for just the function tracing, but CONFIG_FTRACE
> > > > > > really should just be for the function tracing infrastructure, and
> > > > > > perhaps not even include trace events :-/ But at the time it was
> > > > > > created, it was for all the "tracers" (this was added before trace
> > > > > > events).
> > > > >
> > > > > It would be great to see this cleaned up. I found this aspect of how
> > > > > tracing works rather confusing.
> > > > >
> > > > > So do you think it makes sense for the KASAN tests to "select TRACING"
> > > > > for now if the code depends on the trace event infrastructure?
> > > >
> > > > Any thoughts? It looks like someone else got tripped up by this:
> > > > https://reviews.llvm.org/D144057
> > >
> > > Yeah, it really does need to get cleaned up, but unfortunately it's not
> > > going to be a trivial change. We need to make sure it's done in a way that
> > > an old .config still keeps the same things enabled with the new config
> > > settings. That takes some trickery in the dependency.
> > >
> > > I'll add this to my todo list, hopefully it doesn't fall into the abyss
> > > portion of that list :-p
> > >
> > > -- Steve
> >
> > Just adding to Peter's concern re: CONFIG_KASAN_KUNIT_TEST's dependency on
> > CONFIG_TRACEPOINTS.
> >
> > I'm having no luck running the KASan KUnit tests on arm64 with the following
> > .kunitconfig on v6.6.0:
> >
> >         CONFIG_KUNIT=y
> >         CONFIG_KUNIT_ALL_TESTS=n
> >         CONFIG_DEBUG_KERNEL=y
> >         CONFIG_KASAN=y
> >         CINFIG_KASAN_GENERIC=y
> >         CONFIG_KASAN_KUNIT_TEST=y
> >
> > CONFIG_TRACEPOINTS, which CONFIG_KASAN_TEST relies on since the patch this
> > thread is based on, isn't defined for arm64, AFAICT.
> >
> > If I comment out the dependency on CONFIG_TRACEPOINTS, the tests appear to run,
> > but KUnit isn't picking up the KASan output.
> >
> > If I revert the patch, the above .kunitconfig appears to work fine on arm64 and
> > the tests pass.
> >
> > The above .kunitconfig works as intended on X86, no changes necessary.
> >
> > Am I missing something?
> 
> Hi Paul,
> 
> I've been successfully running KASAN tests with CONFIG_TRACEPOINTS
> enabled on arm64 since this patch landed.

Interesting ... 

> What happens when you try running the tests with .kunitconfig? Does
> CONFIG_TRACEPOINTS or CONFIG_KASAN_KUNIT_TEST get disabled during
> kernel building? 

Yes, exactly, that's what's happening.

Here's the output kunit.py is giving me. I replaced CONFIG_DEBUG_KERNEL with 
CONFIG_TRACEPOINTS in my .kunitconfig. Otherwise, it's identical with the one I 
posted above.

	➜   ./tools/testing/kunit/kunit.py run --kunitconfig=mm/kasan/.kunitconfig --arch=arm64
	Configuring KUnit Kernel ...
	Regenerating .config ...
	Populating config with:
	$ make ARCH=arm64 O=.kunit olddefconfig
	ERROR:root:Not all Kconfig options selected in kunitconfig were in the generated .config.
	This is probably due to unsatisfied dependencies.
	Missing: CONFIG_KASAN_KUNIT_TEST=y, CONFIG_TRACEPOINTS=y

Does CONFIG_TRACEPOINTS have some dependency I'm not seeing? I couldn't find a 
reason why it would get disabled, but I could definitely be wrong.

> Or tests just don't get executed?
> 
> Thanks!

Many thanks,
Paul