From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sender4-op-o10.zoho.com (sender4-op-o10.zoho.com [136.143.188.10]) by sourceware.org (Postfix) with ESMTPS id 5EB71383EB34 for ; Tue, 13 Dec 2022 19:13:27 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 5EB71383EB34 Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=yottadb.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=yottadb.com ARC-Seal: i=1; a=rsa-sha256; t=1670958805; cv=none; d=zohomail.com; s=zohoarc; b=XYt4SFH4H754jq+MCIUtXp/IR98b7EfjTUMJUBfADTlkAK+EmN0z2Zzu/V84iE7/xqS5OzEmozFP1BJgu7PkowRaZ8WxHJFeEXH1m0kGIZMWcsAQsZue+CNW2qK+cTI0bdseN8KN54f/SBUGLqvXS57DzjmeUARsvLxJW2kbKaM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1670958805; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=pTXHTdN+9n/ibqAIZSmAI9KwXCING63TJFuAGqEAcYE=; b=jczh+dnNprQK9AkoJm0S6+421mv+9xdCQ5AyzN9BvY6r7lZNA556oXddYLerBxOZZeQ8RsACGgvLHh0ehYm8k8xqRB32SM3M3GeiEBWY8T83z1+iZe0paSNl93/dOutYtzeJzchR9Togx+eAVGMhEVndO1YCINucxUdHTixJ99M= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=yottadb.com; spf=pass smtp.mailfrom=nars@yottadb.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1670958805; s=bam5eec4; d=yottadb.com; i=nars@yottadb.com; h=From:From:To:To:Cc:Cc:References:In-Reply-To:Subject:Subject:Date:Date:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=pTXHTdN+9n/ibqAIZSmAI9KwXCING63TJFuAGqEAcYE=; b=SiMHWZlvx5BT+umbtrN6W/Ait1WHEeFM2Lq2CaEZyXPGDLwGxr7eTxgdF6Uo3rYH CfsiCcf7AUtsjpbD+t2U9dVveJbLRGhnyjAPNl0UpX29ZL/Rx5kPrLnrvqtD9/s2lnm 38hialQs9XImLfsMMn3GAxKY/0sPYpTtvr+YSn6s= Received: from NARSWIN10 (static-71-162-243-192.phlapa.fios.verizon.net [71.162.243.192]) by mx.zohomail.com with SMTPS id 1670958804269425.00962627692957; Tue, 13 Dec 2022 11:13:24 -0800 (PST) From: "Narayanan Iyer" To: "'Noah Goldstein'" Cc: References: <0a1f01d90f1f$96c7ce60$c4576b20$@yottadb.com> In-Reply-To: Subject: RE: Bug 29863 - Segmentation fault in memcmp-sse2.S if memory contents can concurrently change Date: Tue, 13 Dec 2022 14:13:22 -0500 Message-ID: <0b2901d90f26$f82b4720$e881d560$@yottadb.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQKROsKQEAZD5rTjp9SCqSDmRSA/8wI8iibmrOnzPQA= Content-Language: en-us X-Antivirus: Avast (VPS 221213-2, 12/13/2022), Outbound message X-Antivirus-Status: Clean X-ZohoMailClient: External X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,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: Noah, Thank you for acknowledging that it is a bug. In case it helps, I found in our testing cluster, that a system which = uses sysdeps/x86_64/multiarch/memcmp-sse2.S has the bug whereas a system = that uses sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S does not have the = bug. So it is possible, the issue is only in the sse2 version. Thanks, Narayanan. -----Original Message----- From: Noah Goldstein [mailto:goldstein.w.n@gmail.com]=20 Sent: Tuesday, December 13, 2022 2:08 PM To: Narayanan Iyer Cc: libc-alpha@sourceware.org Subject: Re: Bug 29863 - Segmentation fault in memcmp-sse2.S if memory = contents can concurrently change On Tue, Dec 13, 2022 at 10:20 AM Narayanan Iyer via Libc-alpha wrote: > > Hi, > > I had created a glibc bug report at = https://sourceware.org/bugzilla/show_bug.cgi?id=3D29863 > > And have included the title of that report in the email subject as = well. > > It has been a week since I created the issue and I did not hear = anything back. I believe this is a regression in glibc 2.36 and have = provided enough information in the bug report (along with the commit = that caused the regression). > > Given the upcoming glibc 2.37 release, I was asked (by Carlos O'Donell = ) to raise it on this mailing list to get the = attention of the glibc developers. > > I am hoping one of you could take a quick look at the bug report and = see if it is worth fixing it in time for glibc 2.37. > > Thanks, > Narayanan. > > The fix: https://sourceware.org/git/?p=3Dglibc.git;a=3Dblob;f=3Dsysdeps/x86_64/mul= tiarch/memcmp-sse2.S;h=3Dafd450d0206d6633da9fbc4607a7fa6aeb4e137c;hb=3DHE= AD#l46 ``` -# define SIZE_OFFSET (CHAR_PER_VEC * 2) +# define SIZE_OFFSET 0 ``` Is this something we have to support? I believe other functions / implementations of memcmp will suffer from a similar bug.