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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=fbHIgAlgSq4iB7quTf2qhHGKCCFRoCrwGuazo473FaY=; b=ltbmJ99KB5ov74hQUfTwduh5L+SEplIH4O+rwi1jxcEgCdOkT4afmimqHH0rMIeD6m soCjrR+8Tmgs5fk+Rs/gULRK1+rXE2R9kB7NxZR/+94Ya3xAIyWb4hb7oJ7Pu04RHtBp r2blQdQGWNZitX4Srrl0fOovWBUw0bKcg7g80PqMpa7KY1h87ThkmVrvRDhNqGE68ZYS wd1swayq9DtehfAThYg7w2i+5mbu2kQRgEja3ah9knQhqNVQooubi/4o5aLjx4OyblCl 941+XoJaXz9P4RTJxMzcbj0ESMaKqd0psfAzFgbLfdAQCphjLTPVt18sWLfQqQPdeVEV 1DQA== X-Gm-Message-State: AOAM5310jKT0Lpm0V+who6bIR0fT/nNC4I1tUdpsCWGrRwJR4YgxirgC HUfprWGklJW2Rv3QQhbcVLY5QIQrs0BGKbIn X-Google-Smtp-Source: ABdhPJya/d6yn0EDnpT6RqwEgHj+ltwjXL6ylzd9QMErYv21t8cbLpDO8rzJrk1EjI3fAWp9SFLBVqSSmZ7oOn9/ X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:ad4:5a50:: with SMTP id ej16mr8471157qvb.25.1610653001425; Thu, 14 Jan 2021 11:36:41 -0800 (PST) Date: Thu, 14 Jan 2021 20:36:19 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH v3 03/15] kasan: clean up comments in tests From: Andrey Konovalov To: Andrew Morton , Catalin Marinas , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Marco Elver X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210114_143645_189955_AC4E45E6 X-CRM114-Status: GOOD ( 21.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Branislav Rankov , Andrey Konovalov , Kevin Brodsky , Will Deacon , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Andrey Ryabinin , Peter Collingbourne , Evgenii Stepanov Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Clarify and update comments in KASAN tests. Link: https://linux-review.googlesource.com/id/I6c816c51fa1e0eb7aa3dead6bda1f339d2af46c8 Reviewed-by: Marco Elver Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko --- lib/test_kasan.c | 59 +++++++++++++++++++++++++---------------- lib/test_kasan_module.c | 5 ++-- 2 files changed, 39 insertions(+), 25 deletions(-) diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 2947274cc2d3..6f46e27c2af7 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -28,10 +28,9 @@ #define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE) /* - * We assign some test results to these globals to make sure the tests - * are not eliminated as dead code. + * Some tests use these global variables to store return values from function + * calls that could otherwise be eliminated by the compiler as dead code. */ - void *kasan_ptr_result; int kasan_int_result; @@ -39,14 +38,13 @@ static struct kunit_resource resource; static struct kunit_kasan_expectation fail_data; static bool multishot; +/* + * Temporarily enable multi-shot mode. Otherwise, KASAN would only report the + * first detected bug and panic the kernel if panic_on_warn is enabled. + */ static int kasan_test_init(struct kunit *test) { - /* - * Temporarily enable multi-shot mode and set panic_on_warn=0. - * Otherwise, we'd only get a report for the first case. - */ multishot = kasan_save_enable_multi_shot(); - return 0; } @@ -56,12 +54,12 @@ static void kasan_test_exit(struct kunit *test) } /** - * KUNIT_EXPECT_KASAN_FAIL() - Causes a test failure when the expression does - * not cause a KASAN error. This uses a KUnit resource named "kasan_data." Do - * Do not use this name for a KUnit resource outside here. - * + * KUNIT_EXPECT_KASAN_FAIL() - check that the executed expression produces a + * KASAN report; causes a test failure otherwise. This relies on a KUnit + * resource named "kasan_data". Do not use this name for KUnit resources + * outside of KASAN tests. */ -#define KUNIT_EXPECT_KASAN_FAIL(test, condition) do { \ +#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \ fail_data.report_expected = true; \ fail_data.report_found = false; \ kunit_add_named_resource(test, \ @@ -69,7 +67,7 @@ static void kasan_test_exit(struct kunit *test) NULL, \ &resource, \ "kasan_data", &fail_data); \ - condition; \ + expression; \ KUNIT_EXPECT_EQ(test, \ fail_data.report_expected, \ fail_data.report_found); \ @@ -121,7 +119,8 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test) return; } - /* Allocate a chunk that does not fit into a SLUB cache to trigger + /* + * Allocate a chunk that does not fit into a SLUB cache to trigger * the page allocator fallback. */ ptr = kmalloc(size, GFP_KERNEL); @@ -168,7 +167,9 @@ static void kmalloc_large_oob_right(struct kunit *test) { char *ptr; size_t size = KMALLOC_MAX_CACHE_SIZE - 256; - /* Allocate a chunk that is large enough, but still fits into a slab + + /* + * Allocate a chunk that is large enough, but still fits into a slab * and does not trigger the page allocator fallback in SLUB. */ ptr = kmalloc(size, GFP_KERNEL); @@ -469,10 +470,13 @@ static void ksize_unpoisons_memory(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); real_size = ksize(ptr); - /* This access doesn't trigger an error. */ + + /* This access shouldn't trigger a KASAN report. */ ptr[size] = 'x'; - /* This one does. */ + + /* This one must. */ KUNIT_EXPECT_KASAN_FAIL(test, ptr[real_size] = 'y'); + kfree(ptr); } @@ -568,7 +572,7 @@ static void kmem_cache_invalid_free(struct kunit *test) return; } - /* Trigger invalid free, the object doesn't get freed */ + /* Trigger invalid free, the object doesn't get freed. */ KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p + 1)); /* @@ -585,7 +589,10 @@ static void kasan_memchr(struct kunit *test) char *ptr; size_t size = 24; - /* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 */ + /* + * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. + * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. + */ if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { kunit_info(test, "str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT"); @@ -610,7 +617,10 @@ static void kasan_memcmp(struct kunit *test) size_t size = 24; int arr[9]; - /* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 */ + /* + * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. + * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. + */ if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { kunit_info(test, "str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT"); @@ -634,7 +644,10 @@ static void kasan_strings(struct kunit *test) char *ptr; size_t size = 24; - /* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 */ + /* + * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. + * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. + */ if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { kunit_info(test, "str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT"); @@ -706,7 +719,7 @@ static void kasan_bitops_generic(struct kunit *test) } /* - * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes; + * Allocate 1 more byte, which causes kzalloc to round up to 16 bytes; * this way we do not actually corrupt other memory. */ bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL); diff --git a/lib/test_kasan_module.c b/lib/test_kasan_module.c index 3b4cc77992d2..eee017ff8980 100644 --- a/lib/test_kasan_module.c +++ b/lib/test_kasan_module.c @@ -123,8 +123,9 @@ static noinline void __init kasan_workqueue_uaf(void) static int __init test_kasan_module_init(void) { /* - * Temporarily enable multi-shot mode. Otherwise, we'd only get a - * report for the first case. + * Temporarily enable multi-shot mode. Otherwise, KASAN would only + * report the first detected bug and panic the kernel if panic_on_warn + * is enabled. */ bool multishot = kasan_save_enable_multi_shot();