From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-xd2d.google.com (mail-io1-xd2d.google.com [IPv6:2607:f8b0:4864:20::d2d]) by sourceware.org (Postfix) with ESMTPS id F40B03858C83 for ; Tue, 15 Feb 2022 16:50:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org F40B03858C83 Received: by mail-io1-xd2d.google.com with SMTP id w7so24614533ioj.5 for ; Tue, 15 Feb 2022 08:50:23 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Ta7VgTa6mjcGyH+7uedODiibGLg/haFsdQIm/pXum+Y=; b=XUFcUMpf0FUOJ2av+kiFs7PzUKPPVRTWl0PGp8Uk33+8BuvHnmMOyPMV42IaSdqs72 zUyHkPsaRII26sZ6YbInUvsh/8Of0wtu09cQSNwg8N1r/3kCzijDI/7xVXrz5Q2MuiMR 4iTsjq0CKFS3D6cLnhkw8naYLMnEx1sBPqxyV4BkiGv5V5DhSo3YmLrrVccnqsAuRuYZ Ttu9p1+KuUMYdNN8BEIRNb0O73j+R2Qk8LAeYwe/9qIzzO+KPWv6vceaVI2ndz2JhmNB /8CeyuBUE4Xt2qq+VQ9QSWFH3L8dE2DmFFs5Kkujxmx1N00AyhU2zSt7T8BSzkNayA0R YuXA== X-Gm-Message-State: AOAM5327vwwvgStAUa3lYIUqqLBb5tQ7oKPD9RWhfvMvNAEk1Z01JR/t yrtrjMPqMJDJHWrjAN8OmH0FfbtRIRw= X-Google-Smtp-Source: ABdhPJxdIiKz5vvR3IMVphPFmAPtBK63vRkAMLB8aMkwtv0UPXIRSek3bUZuE7V7TwuOcS6VlrGGqA== X-Received: by 2002:a05:6602:17cf:: with SMTP id z15mr1556777iox.188.1644943823253; Tue, 15 Feb 2022 08:50:23 -0800 (PST) Received: from localhost.localdomain (node-17-161.flex.volo.net. [76.191.17.161]) by smtp.googlemail.com with ESMTPSA id s3sm19397625ilp.57.2022.02.15.08.50.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Feb 2022 08:50:22 -0800 (PST) From: Noah Goldstein To: libc-alpha@sourceware.org Subject: [PATCH v2] x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896] Date: Tue, 15 Feb 2022 10:49:36 -0600 Message-Id: <20220215164935.302235-1-goldstein.w.n@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220215162751.281955-1-goldstein.w.n@gmail.com> References: <20220215162751.281955-1-goldstein.w.n@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE, UNWANTED_LANGUAGE_BODY autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Feb 2022 16:50:25 -0000 In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would call strcmp-avx2 and wcsncmp-avx2 respectively. This would have not checks around vzeroupper and would trigger spurious aborts. This commit fixes that. test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass. Note not tested on a machine that supports RTM (non available). --- Did not test the test case. I believe this will cover the bug and is correct but do not have the hardware to check. HJ, can you test this? sysdeps/x86/tst-strncmp-rtm.c | 11 +++++++++++ sysdeps/x86_64/multiarch/strcmp-avx2.S | 8 ++------ sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S | 1 + sysdeps/x86_64/multiarch/strncmp-avx2.S | 1 + sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S | 2 +- sysdeps/x86_64/multiarch/wcsncmp-avx2.S | 2 +- 6 files changed, 17 insertions(+), 8 deletions(-) diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c index 09ed6fa0d6..20ebba319a 100644 --- a/sysdeps/x86/tst-strncmp-rtm.c +++ b/sysdeps/x86/tst-strncmp-rtm.c @@ -45,8 +45,19 @@ function (void) return 1; } +__attribute__ ((noinline, noclone)) +static int +function_overflow (void) +{ + if (strncmp (string1, string2, SIZE_MAX) == 0) + return 0; + else + return 1; +} + static int do_test (void) { return do_test_1 ("strncmp", LOOP, prepare, function); + return do_test_1 ("strncmp", LOOP, prepare, function_overflow); } diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S index 07a5a2c889..52ff5ad724 100644 --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S @@ -193,10 +193,10 @@ L(ret_zero): .p2align 4,, 5 L(one_or_less): jb L(ret_zero) -# ifdef USE_AS_WCSCMP /* 'nbe' covers the case where length is negative (large unsigned). */ - jnbe __wcscmp_avx2 + jnbe OVERFLOW_STRCMP +# ifdef USE_AS_WCSCMP movl (%rdi), %edx xorl %eax, %eax cmpl (%rsi), %edx @@ -205,10 +205,6 @@ L(one_or_less): negl %eax orl $1, %eax # else - /* 'nbe' covers the case where length is negative (large - unsigned). */ - - jnbe __strcmp_avx2 movzbl (%rdi), %eax movzbl (%rsi), %ecx subl %ecx, %eax diff --git a/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S b/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S index 37d1224bb9..68bad365ba 100644 --- a/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S +++ b/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S @@ -1,3 +1,4 @@ #define STRCMP __strncmp_avx2_rtm #define USE_AS_STRNCMP 1 +#define OVERFLOW_STRCMP __strcmp_avx2_rtm #include "strcmp-avx2-rtm.S" diff --git a/sysdeps/x86_64/multiarch/strncmp-avx2.S b/sysdeps/x86_64/multiarch/strncmp-avx2.S index 1678bcc235..f138e9f1fd 100644 --- a/sysdeps/x86_64/multiarch/strncmp-avx2.S +++ b/sysdeps/x86_64/multiarch/strncmp-avx2.S @@ -1,3 +1,4 @@ #define STRCMP __strncmp_avx2 #define USE_AS_STRNCMP 1 +#define OVERFLOW_STRCMP __strcmp_avx2 #include "strcmp-avx2.S" diff --git a/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S b/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S index 4e88c70cc6..f467582cbe 100644 --- a/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S +++ b/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S @@ -1,5 +1,5 @@ #define STRCMP __wcsncmp_avx2_rtm #define USE_AS_STRNCMP 1 #define USE_AS_WCSCMP 1 - +#define OVERFLOW_STRCMP __wcscmp_avx2_rtm #include "strcmp-avx2-rtm.S" diff --git a/sysdeps/x86_64/multiarch/wcsncmp-avx2.S b/sysdeps/x86_64/multiarch/wcsncmp-avx2.S index 4fa1de4d3f..e9ede522b8 100644 --- a/sysdeps/x86_64/multiarch/wcsncmp-avx2.S +++ b/sysdeps/x86_64/multiarch/wcsncmp-avx2.S @@ -1,5 +1,5 @@ #define STRCMP __wcsncmp_avx2 #define USE_AS_STRNCMP 1 #define USE_AS_WCSCMP 1 - +#define OVERFLOW_STRCMP __wcscmp_avx2 #include "strcmp-avx2.S" -- 2.25.1