Re: [PATCH mm] another fix for "kasan: improve vmalloc tests"

From: Marco Elver <elver@google.com>
To: Andrey Konovalov <andreyknvl@gmail.com>
Cc: 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 <kasan-dev@googlegroups.com>,
	Linux Memory Management List <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrey Konovalov <andreyknvl@google.com>,
	kernel test robot <lkp@intel.com>
Subject: Re: [PATCH mm] another fix for "kasan: improve vmalloc tests"
Date: Tue, 22 Feb 2022 19:10:55 +0100	[thread overview]
Message-ID: <CANpmjNN3-qX_brk9PTW0MkF0H=-DeM+n_ccge_QQ07oKBPx74w@mail.gmail.com> (raw)
In-Reply-To: <CA+fCnZf2jE1N8j9iQRtOnQsTP=2CQOGYqREbzypPQa-=UXjhDA@mail.gmail.com>

On Tue, 22 Feb 2022 at 19:08, Andrey Konovalov <andreyknvl@gmail.com> wrote:
>
> On Tue, Feb 22, 2022 at 6:50 PM Marco Elver <elver@google.com> wrote:
> >
> > On Tue, 22 Feb 2022 at 18:10, <andrey.konovalov@linux.dev> wrote:
> > >
> > > From: Andrey Konovalov <andreyknvl@google.com>
> > >
> > > set_memory_rw/ro() are not exported to be used in modules and thus
> > > cannot be used in KUnit-compatible KASAN tests.
> > >
> > > Drop the checks that rely on these functions.
> > >
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> > > ---
> > >  lib/test_kasan.c | 6 ------
> > >  1 file changed, 6 deletions(-)
> > >
> > > diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> > > index ef99d81fe8b3..448194bbc41d 100644
> > > --- a/lib/test_kasan.c
> > > +++ b/lib/test_kasan.c
> > > @@ -1083,12 +1083,6 @@ static void vmalloc_helpers_tags(struct kunit *test)
> > >         KUNIT_ASSERT_TRUE(test, is_vmalloc_addr(ptr));
> > >         KUNIT_ASSERT_NOT_ERR_OR_NULL(test, vmalloc_to_page(ptr));
> > >
> > > -       /* Make sure vmalloc'ed memory permissions can be changed. */
> > > -       rv = set_memory_ro((unsigned long)ptr, 1);
> > > -       KUNIT_ASSERT_GE(test, rv, 0);
> > > -       rv = set_memory_rw((unsigned long)ptr, 1);
> > > -       KUNIT_ASSERT_GE(test, rv, 0);
> >
> > You can still test it by checking 'ifdef MODULE'. You could add a
> > separate test which is skipped if MODULE is defined. Does that work?
>
> Yes, putting it under ifdef will work. I thought that having a
> discrepancy between built-in and module tests is weird, but I see the
> kprobes tests doing this, so maybe it's not such a bad idea. Will do
> in v2.

Additionally you could have the test skip with kunit_skip(), so it's
at least visible. The code itself has to be #ifdef'd I guess because
set_memory_*() aren't even declared ifdef MODULE (I think?).