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Thu, 12 Aug 2021 01:56:43 -0700 (PDT) MIME-Version: 1.0 References: <3773f984cbd64f008af9b03e82fc1b317cda9fda.1628709663.git.andreyknvl@gmail.com> In-Reply-To: <3773f984cbd64f008af9b03e82fc1b317cda9fda.1628709663.git.andreyknvl@gmail.com> From: Marco Elver Date: Thu, 12 Aug 2021 10:56:32 +0200 Message-ID: Subject: Re: [PATCH 6/8] kasan: test: clean up ksize_uaf To: andrey.konovalov@linux.dev Cc: Andrew Morton , Andrey Konovalov , Andrey Ryabinin , Dmitry Vyukov , Alexander Potapenko , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 98926503D86E X-Stat-Signature: qw66usiksupkr5xxe8zcj98foaqftibg Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b="hPI9bp/G"; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf05.hostedemail.com: domain of elver@google.com designates 209.85.210.52 as permitted sender) smtp.mailfrom=elver@google.com X-HE-Tag: 1628758604-324337 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 11 Aug 2021 at 21:23, wrote: > > From: Andrey Konovalov > > Some KASAN tests use global variables to store function returns values > so that the compiler doesn't optimize away these functions. > > ksize_uaf() doesn't call any functions, so it doesn't need to use > kasan_int_result. Use volatile accesses instead, to be consistent with > other similar tests. > > Signed-off-by: Andrey Konovalov Reviewed-by: Marco Elver Although I do wonder if the compiler might one day mess with the volatile reads. At least this way we might also catch if the compiler messes up volatile reads. ;-) > --- > lib/test_kasan.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/lib/test_kasan.c b/lib/test_kasan.c > index efd0da5c750f..e159d24b3b49 100644 > --- a/lib/test_kasan.c > +++ b/lib/test_kasan.c > @@ -731,8 +731,8 @@ static void ksize_uaf(struct kunit *test) > kfree(ptr); > > KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr)); > - KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *ptr); > - KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *(ptr + size)); > + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); > + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]); > } > > static void kasan_stack_oob(struct kunit *test) > -- > 2.25.1 >