From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-x232.google.com (mail-oi1-x232.google.com [IPv6:2607:f8b0:4864:20::232]) by sourceware.org (Postfix) with ESMTPS id 0EB08384F481; Thu, 24 Nov 2022 03:04:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 0EB08384F481 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-oi1-x232.google.com with SMTP id l127so363542oia.8; Wed, 23 Nov 2022 19:04:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=lzPKRdgKYkS7xAIofXnJoCm6jbfc5TdSBFXn+uiGDDI=; b=IjwpNuThLeRMPHGi7ngPiyGWTSAvqBZynk1Ro+Pw1LZPIwVWsYxsF4SeZMtE0sqpnu 8uhIcitvIhyAXfKdcLv42nYLGUh5zb7n9GlBljV7OEm0PIl1BoW0UkGdleFGIKrdFdUt 1TQa5APgLmsEoIVXsG17NjgTB7irnYbgyQwYZzEbNW5p6FmVrh3htq8WBaXUi+lgYysl Alg3uI67IKEZ4Ux1FwM2zPZvVYV/Lw7regtuNK3RyGbA5uzauf/zWotrZAm3EyXag94E 0GaaJ7z++bBWB6M5OXGJ59jpNedazgaOWMwrDor80HoJWqQ0dl6LT2lvdl/KBMaNeJxC z1vQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=lzPKRdgKYkS7xAIofXnJoCm6jbfc5TdSBFXn+uiGDDI=; b=Ejmh4h+o+pKlHgZA70CWpOV+o+0d2E7MvmxfDFEhf2fTm0YYVW0edxsKV0CXcP62uC T1/ODdV17FVIp0a+gqD4Vr/BJ0MFRyP6w6ZpDtssPuLhao+GQ0e7TDvfuSi9K3GJhChP Q3SVN0uGVS+p+LOjJG/qkQgi/XIBaUfnR4lUFjNTdPfqW+oPLTgKUtjO125PTo7uGgs5 RoB+qgKxhwFPGVM7+XikKTn3vTl9rsloha1bBwgBlA31qmVS3RqD0R+jAQZXGIOZiDh4 haw94RUrbkhMWTlELmdLpevMklJIPCR9sKVXM5Zd+YZBVPmy+wjONLiOkrMA9oXuiieH AIxw== X-Gm-Message-State: ANoB5plkFCfuZOmFH/40p0iiy4qgFeXSRjifVrcKSvNxPcylXAp9CPjQ 3Gh+7/HPtgKojfAZ59fV6cevuKc+M8rvD7ECPpZK9u/w X-Google-Smtp-Source: AA0mqf5yp1DdvXzJbyCX26LeqBE3o+Hqm6l80NnbxprjWcVG6B07xWhLBl+hArR3ycfmSHvk5SuaKiCDFeBz1LRO4e4= X-Received: by 2002:a05:6808:1824:b0:357:65d7:1427 with SMTP id bh36-20020a056808182400b0035765d71427mr15885566oib.105.1669259086241; Wed, 23 Nov 2022 19:04:46 -0800 (PST) MIME-Version: 1.0 References: <20220921005804.7131-1-goldstein.w.n@gmail.com> In-Reply-To: From: Sunil Pandey Date: Wed, 23 Nov 2022 19:04:10 -0800 Message-ID: Subject: Re: [PATCH v1] x86: Fix wcsnlen-avx2 page cross length comparison [BZ #29591] To: "H.J. Lu" Cc: Libc-stable Mailing List , Noah Goldstein , libc-alpha@sourceware.org Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-7.2 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,GIT_PATCH_0,HK_RANDOM_ENVFROM,HK_RANDOM_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Wed, Nov 23, 2022 at 4:23 PM H.J. Lu wrote: > > On Wed, Nov 23, 2022 at 2:21 PM Sunil Pandey wrote: > > > > On Wed, Sep 21, 2022 at 3:02 PM H.J. Lu via Libc-alpha > > wrote: > > > > > > On Tue, Sep 20, 2022 at 5:58 PM Noah Goldstein wrote: > > > > > > > > Previous implementation was adjusting length (rsi) to match > > > > bytes (eax), but since there is no bound to length this can cause > > > > overflow. > > > > > > > > Fix is to just convert the byte-count (eax) to length by dividing by > > > > sizeof (wchar_t) before the comparison. > > > > > > > > Full check passes on x86-64 and build succeeds w/ and w/o multiarch. > > > > --- > > > > string/test-strnlen.c | 70 +++++++++++++++----------- > > > > sysdeps/x86_64/multiarch/strlen-avx2.S | 7 +-- > > > > 2 files changed, 43 insertions(+), 34 deletions(-) > > > > > > > > diff --git a/string/test-strnlen.c b/string/test-strnlen.c > > > > index 4a9375112a..5cbaf4b734 100644 > > > > --- a/string/test-strnlen.c > > > > +++ b/string/test-strnlen.c > > > > @@ -73,7 +73,7 @@ do_test (size_t align, size_t len, size_t maxlen, int max_char) > > > > { > > > > size_t i; > > > > > > > > - align &= 63; > > > > + align &= (getpagesize () / sizeof (CHAR) - 1); > > > > if ((align + len) * sizeof (CHAR) >= page_size) > > > > return; > > > > > > > > @@ -90,38 +90,50 @@ do_test (size_t align, size_t len, size_t maxlen, int max_char) > > > > static void > > > > do_overflow_tests (void) > > > > { > > > > - size_t i, j, len; > > > > + size_t i, j, al_idx, repeats, len; > > > > const size_t one = 1; > > > > uintptr_t buf_addr = (uintptr_t) buf1; > > > > + const size_t alignments[] = { 0, 1, 7, 9, 31, 33, 63, 65, 95, 97, 127, 129 }; > > > > > > > > - for (i = 0; i < 750; ++i) > > > > + for (al_idx = 0; al_idx < sizeof (alignments) / sizeof (alignments[0]); > > > > + al_idx++) > > > > { > > > > - do_test (1, i, SIZE_MAX, BIG_CHAR); > > > > - > > > > - do_test (0, i, SIZE_MAX - i, BIG_CHAR); > > > > - do_test (0, i, i - buf_addr, BIG_CHAR); > > > > - do_test (0, i, -buf_addr - i, BIG_CHAR); > > > > - do_test (0, i, SIZE_MAX - buf_addr - i, BIG_CHAR); > > > > - do_test (0, i, SIZE_MAX - buf_addr + i, BIG_CHAR); > > > > - > > > > - len = 0; > > > > - for (j = 8 * sizeof(size_t) - 1; j ; --j) > > > > - { > > > > - len |= one << j; > > > > - do_test (0, i, len - i, BIG_CHAR); > > > > - do_test (0, i, len + i, BIG_CHAR); > > > > - do_test (0, i, len - buf_addr - i, BIG_CHAR); > > > > - do_test (0, i, len - buf_addr + i, BIG_CHAR); > > > > - > > > > - do_test (0, i, ~len - i, BIG_CHAR); > > > > - do_test (0, i, ~len + i, BIG_CHAR); > > > > - do_test (0, i, ~len - buf_addr - i, BIG_CHAR); > > > > - do_test (0, i, ~len - buf_addr + i, BIG_CHAR); > > > > - > > > > - do_test (0, i, -buf_addr, BIG_CHAR); > > > > - do_test (0, i, j - buf_addr, BIG_CHAR); > > > > - do_test (0, i, -buf_addr - j, BIG_CHAR); > > > > - } > > > > + for (repeats = 0; repeats < 2; ++repeats) > > > > + { > > > > + size_t align = repeats ? (getpagesize () - alignments[al_idx]) > > > > + : alignments[al_idx]; > > > > + align /= sizeof (CHAR); > > > > + for (i = 0; i < 750; ++i) > > > > + { > > > > + do_test (align, i, SIZE_MAX, BIG_CHAR); > > > > + > > > > + do_test (align, i, SIZE_MAX - i, BIG_CHAR); > > > > + do_test (align, i, i - buf_addr, BIG_CHAR); > > > > + do_test (align, i, -buf_addr - i, BIG_CHAR); > > > > + do_test (align, i, SIZE_MAX - buf_addr - i, BIG_CHAR); > > > > + do_test (align, i, SIZE_MAX - buf_addr + i, BIG_CHAR); > > > > + > > > > + len = 0; > > > > + for (j = 8 * sizeof (size_t) - 1; j; --j) > > > > + { > > > > + len |= one << j; > > > > + do_test (align, i, len, BIG_CHAR); > > > > + do_test (align, i, len - i, BIG_CHAR); > > > > + do_test (align, i, len + i, BIG_CHAR); > > > > + do_test (align, i, len - buf_addr - i, BIG_CHAR); > > > > + do_test (align, i, len - buf_addr + i, BIG_CHAR); > > > > + > > > > + do_test (align, i, ~len - i, BIG_CHAR); > > > > + do_test (align, i, ~len + i, BIG_CHAR); > > > > + do_test (align, i, ~len - buf_addr - i, BIG_CHAR); > > > > + do_test (align, i, ~len - buf_addr + i, BIG_CHAR); > > > > + > > > > + do_test (align, i, -buf_addr, BIG_CHAR); > > > > + do_test (align, i, j - buf_addr, BIG_CHAR); > > > > + do_test (align, i, -buf_addr - j, BIG_CHAR); > > > > + } > > > > + } > > > > + } > > > > } > > > > } > > > > > > > > diff --git a/sysdeps/x86_64/multiarch/strlen-avx2.S b/sysdeps/x86_64/multiarch/strlen-avx2.S > > > > index 0593fb303b..b9b58ef599 100644 > > > > --- a/sysdeps/x86_64/multiarch/strlen-avx2.S > > > > +++ b/sysdeps/x86_64/multiarch/strlen-avx2.S > > > > @@ -544,14 +544,11 @@ L(return_vzeroupper): > > > > L(cross_page_less_vec): > > > > tzcntl %eax, %eax > > > > # ifdef USE_AS_WCSLEN > > > > - /* NB: Multiply length by 4 to get byte count. */ > > > > - sall $2, %esi > > > > + /* NB: Divide by 4 to convert from byte-count to length. */ > > > > + shrl $2, %eax > > > > # endif > > > > cmpq %rax, %rsi > > > > cmovb %esi, %eax > > > > -# ifdef USE_AS_WCSLEN > > > > - shrl $2, %eax > > > > -# endif > > > > VZEROUPPER_RETURN > > > > # endif > > > > > > > > -- > > > > 2.34.1 > > > > > > > > > > LGTM. > > > > > > Thanks. > > > > > > -- > > > H.J. > > > > I would like to backport this patch to affected release branches from > > 2.36 to 2.33. > > > > Any comments/suggestions or objections on this. > > > > OK. > > Thanks. > > > -- > H.J. Just ran testing from 2.32 to 2.26. All of them have this issue. Ok for 2.32 to 2.26 branches? --Sunil