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Date:   Tue, 28 Nov 2023 16:12:31 +0100
From:   Maxime Ripard <mripard@kernel.org>
To:     Dan Carpenter <dan.carpenter@linaro.org>
Cc:     Naresh Kamboju <naresh.kamboju@linaro.org>,
        Richard Fitzgerald <rf@opensource.cirrus.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Kees Cook <keescook@chromium.org>,
        Daniel =?utf-8?B?RMOtYXo=?= <daniel.diaz@linaro.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Brendan Higgins <brendan.higgins@linux.dev>,
        David Gow <davidgow@google.com>,
        =?utf-8?B?TWHDrXJh?= Canal <mcanal@igalia.com>,
        Arthur Grillo <arthurgrillo@riseup.net>,
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        Ville =?utf-8?B?U3lyasOkbMOk?= <ville.syrjala@linux.intel.com>,
        kv-team <kv-team@linaro.org>
Subject: Re: [RFC] drm/tests: annotate intentional stack trace in
 drm_test_rect_calc_hscale()
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Hi Dan,

On Wed, Nov 15, 2023 at 05:42:17PM -0500, Dan Carpenter wrote:
> On Mon, Nov 06, 2023 at 02:58:12PM +0100, mripard@kernel.org wrote:
> > > But a similar thing is happening here where we have so many bogus
> > > warnings that we missed a real bug.
> >=20
> > IIRC, there was a similar discussion for lockdep issues. IMO, any
> > (unintended) warning should trigger a test failure.
> >=20
> > I guess that would require adding some intrumentation to __WARN somehow,
> > and also allowing tests to check whether a warning had been generated
> > during their execution for tests that want to trigger one.
>=20
> I think this is a good idea.  I was looking at how lockdep prints
> warnings (see print_circular_bug_header()).  It doesn't use WARN() it
> prints a bunch of pr_warn() statements and then a stack trace.  We would
> have to have a increment the counter manually in that situation.
>=20
> I'm writing a script to parse a dmesg and collect Oopses.

Do we need to? I was only expecting a boolean to be set or kunit_fail to
be called in the WARN/lockdep warning code path if a test is running?

> So now I know to look for WARN(), lockdep, and KASAN. What other bugs
> formats do we have? Probably someone like the syzbot devs have already
> has written a script like this?

I think you got most of it covered, I can't think of any other source of
failure right now.

Maxime

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