Re: [RFC PATCH 2/2] KUnit: KASAN Integration

From: Patricia Alfonso <trishalfonso@google.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Brendan Higgins <brendanhiggins@google.com>,
	David Gow <davidgow@google.com>, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	vincent.guittot@linaro.org, LKML <linux-kernel@vger.kernel.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	"open list:KERNEL SELFTEST FRAMEWORK" 
	<linux-kselftest@vger.kernel.org>,
	kunit-dev@googlegroups.com
Subject: Re: [RFC PATCH 2/2] KUnit: KASAN Integration
Date: Fri, 28 Feb 2020 17:23:07 -0800	[thread overview]
Message-ID: <CAKFsvUJFovti=enpOefqMbtQpeorihQhugH3-1nv0BBwevCwQg@mail.gmail.com> (raw)
In-Reply-To: <CACT4Y+YFewcbRnY62wLHueVNwyXCSZwO8K7SUR2cg=pxZv8uZA@mail.gmail.com>

On Thu, Feb 27, 2020 at 6:43 AM Dmitry Vyukov <dvyukov@google.com> wrote:
>
> On Thu, Feb 27, 2020 at 3:44 AM 'Patricia Alfonso' via kasan-dev
> <kasan-dev@googlegroups.com> wrote:
> >
> > Integrate KASAN into KUnit testing framework.
> >  - Fail tests when KASAN reports an error that is not expected
> >  - Use KUNIT_EXPECT_KASAN_FAIL to expect a KASAN error in KASAN tests
> >  - KUnit struct added to current task to keep track of the current test
> > from KASAN code
> >  - Booleans representing if a KASAN report is expected and if a KASAN
> >  report is found added to kunit struct
> >  - This prints "line# has passed" or "line# has failed"
> >
> > Signed-off-by: Patricia Alfonso <trishalfonso@google.com>
> > ---
> > If anyone has any suggestions on how best to print the failure
> > messages, please share!
> >
> > One issue I have found while testing this is the allocation fails in
> > kmalloc_pagealloc_oob_right() sometimes, but not consistently. This
> > does cause the test to fail on the KUnit side, as expected, but it
> > seems to skip all the tests before this one because the output starts
> > with this failure instead of with the first test, kmalloc_oob_right().
>
> I don't follow this... we don't check output in any way, so how does
> output affect execution?...
>
I'm sorry. I think I was just reading the results wrong before - no
wonder I was confused!

I just recreated the error and it does work as expected.

>
> > --- a/tools/testing/kunit/kunit_kernel.py
> > +++ b/tools/testing/kunit/kunit_kernel.py
> > @@ -141,7 +141,7 @@ class LinuxSourceTree(object):
> >                 return True
> >
> >         def run_kernel(self, args=[], timeout=None, build_dir=''):
> > -               args.extend(['mem=256M'])
> > +               args.extend(['mem=256M', 'kasan_multi_shot'])
>
> This is better done somewhere else (different default value if
> KASAN_TEST is enabled or something). Or overridden in the KASAN tests.
> Not everybody uses tools/testing/kunit/kunit_kernel.py and this seems
> to be a mandatory part now. This means people will always hit this, be
> confused, figure out they need to flip the value, and only then be
> able to run kunit+kasan.
>
I agree. Is the best way to do this with "bool multishot =
kasan_save_enable_multi_shot();"  and
"kasan_restore_multi_shot(multishot);" inside test_kasan.c like what
was done in the tests before?

-- 
Thank you,
Patricia Alfonso