linux-kernel - [PATCH 6/8] kasan: test: clean up ksize

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Date:   Wed, 11 Aug 2021 21:23:27 +0200
From:   andrey.konovalov@...ux.dev
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Andrey Konovalov <andreyknvl@...il.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Marco Elver <elver@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        kasan-dev@...glegroups.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 6/8] kasan: test: clean up ksize_uaf

From: Andrey Konovalov <andreyknvl@...il.com>

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 <andreyknvl@...il.com>
---
 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