From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A9C6C77B6E for ; Tue, 28 Mar 2023 23:22:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229904AbjC1XWH (ORCPT ); Tue, 28 Mar 2023 19:22:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229762AbjC1XVk (ORCPT ); Tue, 28 Mar 2023 19:21:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1D371985 for ; Tue, 28 Mar 2023 16:21:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B383D619A3 for ; Tue, 28 Mar 2023 23:21:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A444C433D2; Tue, 28 Mar 2023 23:21:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1680045692; bh=cNOWiSoTtxQRbpDxc5WztpNrHtFKskPUnyFtfljvG5c=; h=Date:To:From:Subject:From; b=Cg0b6g8bAJYeJ44+lOfkuV2XsnEJ4xMs5CovK/IOsgKPKDhxsbcSYHIHZ09hUFfVp jpVcYerCNsA8RThwqBGQXVp2TxXk59TrgWfoRrlQEj7w3YNlSjFZxNPAyv2rDtnxeo 3qs4xtyTs8x0r6JJ0HDbDhJK528dWgK+0sO6WKKs= Date: Tue, 28 Mar 2023 16:21:31 -0700 To: mm-commits@vger.kernel.org, penguin-kernel@i-love.sakura.ne.jp, keescook@chromium.org, geert@linux-m68k.org, elver@google.com, deller@gmx.de, daniel@ffwll.ch, glider@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] kmsan-another-take-at-fixing-memcpy-tests.patch removed from -mm tree Message-Id: <20230328232132.1A444C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: kmsan: another take at fixing memcpy tests has been removed from the -mm tree. Its filename was kmsan-another-take-at-fixing-memcpy-tests.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Alexander Potapenko Subject: kmsan: another take at fixing memcpy tests Date: Fri, 3 Mar 2023 15:14:31 +0100 commit 5478afc55a21 ("kmsan: fix memcpy tests") uses OPTIMIZER_HIDE_VAR() to hide the uninitialized var from the compiler optimizations. However OPTIMIZER_HIDE_VAR(uninit) enforces an immediate check of @uninit, so memcpy tests did not actually check the behavior of memcpy(), because they always contained a KMSAN report. Replace OPTIMIZER_HIDE_VAR() with a file-local macro that just clobbers the memory with a barrier(), and add a test case for memcpy() that does not expect an error report. Also reflow kmsan_test.c with clang-format. Link: https://lkml.kernel.org/r/20230303141433.3422671-2-glider@google.com Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver Cc: Daniel Vetter Cc: Geert Uytterhoeven Cc: Helge Deller Cc: Kees Cook Cc: Tetsuo Handa Signed-off-by: Andrew Morton --- mm/kmsan/kmsan_test.c | 44 ++++++++++++++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 6 deletions(-) --- a/mm/kmsan/kmsan_test.c~kmsan-another-take-at-fixing-memcpy-tests +++ a/mm/kmsan/kmsan_test.c @@ -408,6 +408,37 @@ static void test_printk(struct kunit *te } /* + * Prevent the compiler from optimizing @var away. Without this, Clang may + * notice that @var is uninitialized and drop memcpy() calls that use it. + * + * There is OPTIMIZER_HIDE_VAR() in linux/compier.h that we cannot use here, + * because it is implemented as inline assembly receiving @var as a parameter + * and will enforce a KMSAN check. Same is true for e.g. barrier_data(var). + */ +#define DO_NOT_OPTIMIZE(var) barrier() + +/* + * Test case: ensure that memcpy() correctly copies initialized values. + * Also serves as a regression test to ensure DO_NOT_OPTIMIZE() does not cause + * extra checks. + */ +static void test_init_memcpy(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + volatile int src; + volatile int dst = 0; + + DO_NOT_OPTIMIZE(src); + src = 1; + kunit_info( + test, + "memcpy()ing aligned initialized src to aligned dst (no reports)\n"); + memcpy((void *)&dst, (void *)&src, sizeof(src)); + kmsan_check_memory((void *)&dst, sizeof(dst)); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* * Test case: ensure that memcpy() correctly copies uninitialized values between * aligned `src` and `dst`. */ @@ -420,7 +451,7 @@ static void test_memcpy_aligned_to_align kunit_info( test, "memcpy()ing aligned uninit src to aligned dst (UMR report)\n"); - OPTIMIZER_HIDE_VAR(uninit_src); + DO_NOT_OPTIMIZE(uninit_src); memcpy((void *)&dst, (void *)&uninit_src, sizeof(uninit_src)); kmsan_check_memory((void *)&dst, sizeof(dst)); KUNIT_EXPECT_TRUE(test, report_matches(&expect)); @@ -443,7 +474,7 @@ static void test_memcpy_aligned_to_unali kunit_info( test, "memcpy()ing aligned uninit src to unaligned dst (UMR report)\n"); - OPTIMIZER_HIDE_VAR(uninit_src); + DO_NOT_OPTIMIZE(uninit_src); memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src)); kmsan_check_memory((void *)dst, 4); KUNIT_EXPECT_TRUE(test, report_matches(&expect)); @@ -467,13 +498,14 @@ static void test_memcpy_aligned_to_unali kunit_info( test, "memcpy()ing aligned uninit src to unaligned dst - part 2 (UMR report)\n"); - OPTIMIZER_HIDE_VAR(uninit_src); + DO_NOT_OPTIMIZE(uninit_src); memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src)); kmsan_check_memory((void *)&dst[4], sizeof(uninit_src)); KUNIT_EXPECT_TRUE(test, report_matches(&expect)); } -static noinline void fibonacci(int *array, int size, int start) { +static noinline void fibonacci(int *array, int size, int start) +{ if (start < 2 || (start == size)) return; array[start] = array[start - 1] + array[start - 2]; @@ -482,8 +514,7 @@ static noinline void fibonacci(int *arra static void test_long_origin_chain(struct kunit *test) { - EXPECTATION_UNINIT_VALUE_FN(expect, - "test_long_origin_chain"); + EXPECTATION_UNINIT_VALUE_FN(expect, "test_long_origin_chain"); /* (KMSAN_MAX_ORIGIN_DEPTH * 2) recursive calls to fibonacci(). */ volatile int accum[KMSAN_MAX_ORIGIN_DEPTH * 2 + 2]; int last = ARRAY_SIZE(accum) - 1; @@ -515,6 +546,7 @@ static struct kunit_case kmsan_test_case KUNIT_CASE(test_uaf), KUNIT_CASE(test_percpu_propagate), KUNIT_CASE(test_printk), + KUNIT_CASE(test_init_memcpy), KUNIT_CASE(test_memcpy_aligned_to_aligned), KUNIT_CASE(test_memcpy_aligned_to_unaligned), KUNIT_CASE(test_memcpy_aligned_to_unaligned2), _ Patches currently in -mm which might be from glider@google.com are