Re: [PATCH v1 8/8] kunit: Add tests for faults

From: "Mickaël Salaün" <mic@digikod.net>
To: Kees Cook <keescook@chromium.org>
Cc: Brendan Higgins <brendanhiggins@google.com>,
	 David Gow <davidgow@google.com>, Rae Moar <rmoar@google.com>,
	 Shuah Khan <skhan@linuxfoundation.org>,
	Alan Maguire <alan.maguire@oracle.com>,
	 Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	 "H . Peter Anvin" <hpa@zytor.com>,
	Ingo Molnar <mingo@redhat.com>,
	 James Morris <jamorris@linux.microsoft.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	 "Madhavan T . Venkataraman" <madvenka@linux.microsoft.com>,
	Marco Pagani <marpagan@redhat.com>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	 Stephen Boyd <sboyd@kernel.org>,
	Thara Gopinath <tgopinath@microsoft.com>,
	 Thomas Gleixner <tglx@linutronix.de>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	 Wanpeng Li <wanpengli@tencent.com>,
	Zahra Tarkhani <ztarkhani@microsoft.com>,
	kvm@vger.kernel.org,  linux-hardening@vger.kernel.org,
	linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-security-module@vger.kernel.org,
	linux-um@lists.infradead.org, x86@kernel.org
Subject: Re: [PATCH v1 8/8] kunit: Add tests for faults
Date: Fri, 1 Mar 2024 20:16:05 +0100	[thread overview]
Message-ID: <20240301.aekiung2aL7K@digikod.net> (raw)
In-Reply-To: <202402291027.6F0E4994@keescook>

On Thu, Feb 29, 2024 at 10:28:18AM -0800, Kees Cook wrote:
> On Thu, Feb 29, 2024 at 06:04:09PM +0100, Mickaël Salaün wrote:
> > The first test checks NULL pointer dereference and make sure it would
> > result as a failed test.
> > 
> > The second and third tests check that read-only data is indeed read-only
> > and trying to modify it would result as a failed test.
> > 
> > This kunit_x86_fault test suite is marked as skipped when run on a
> > non-x86 native architecture.  It is then skipped on UML because such
> > test would result to a kernel panic.
> > 
> > Tested with:
> > ./tools/testing/kunit/kunit.py run --arch x86_64 kunit_x86_fault
> > 
> > Cc: Brendan Higgins <brendanhiggins@google.com>
> > Cc: David Gow <davidgow@google.com>
> > Cc: Rae Moar <rmoar@google.com>
> > Cc: Shuah Khan <skhan@linuxfoundation.org>
> > Signed-off-by: Mickaël Salaün <mic@digikod.net>
> 
> If we can add some way to collect WARN/BUG output for examination, I
> could rewrite most of LKDTM in KUnit! I really like this!

Thanks!  About the WARN/BUG examination, I guess the easier way would be
to do in in user space by extending kunit_parser.py.

> 
> > ---
> >  lib/kunit/kunit-test.c | 115 ++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 114 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c
> > index f7980ef236a3..57d8eff00c66 100644
> > --- a/lib/kunit/kunit-test.c
> > +++ b/lib/kunit/kunit-test.c
> > @@ -10,6 +10,7 @@
> >  #include <kunit/test-bug.h>
> >  
> >  #include <linux/device.h>
> > +#include <linux/init.h>
> >  #include <kunit/device.h>
> >  
> >  #include "string-stream.h"
> > @@ -109,6 +110,117 @@ static struct kunit_suite kunit_try_catch_test_suite = {
> >  	.test_cases = kunit_try_catch_test_cases,
> >  };
> >  
> > +#ifdef CONFIG_X86
> 
> Why is this x86 specific?

Because I didn't test on other architecture, and it looks it crashed on
arm64. :)

I'll test on arm64 and change this condition with !CONFIG_UML.

> 
> -- 
> Kees Cook
> 