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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F0860EB64DA for ; Wed, 5 Jul 2023 08:52:46 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Qwths1xqVz3c20 for ; Wed, 5 Jul 2023 18:52:45 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=leemhuis.info (client-ip=80.237.130.52; helo=wp530.webpack.hosteurope.de; envelope-from=regressions@leemhuis.info; receiver=lists.ozlabs.org) Received: from wp530.webpack.hosteurope.de (wp530.webpack.hosteurope.de [80.237.130.52]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QwthH3thBz301T for ; Wed, 5 Jul 2023 18:52:14 +1000 (AEST) Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1qGyF1-0002O0-Fp; Wed, 05 Jul 2023 10:52:03 +0200 Message-ID: <7668c45a-70b1-dc2f-d0f5-c0e76ec17145@leemhuis.info> Date: Wed, 5 Jul 2023 10:51:57 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: Fwd: Memory corruption in multithreaded user space program while calling fork Content-Language: en-US, de-DE To: Suren Baghdasaryan , Andrew Morton References: <5c7455db-4ed8-b54f-e2d5-d2811908123d@leemhuis.info> <2023070359-evasive-regroup-f3b8@gregkh> <2023070453-plod-swipe-cfbf@gregkh> <20230704091808.aa2ed3c11a5351d9bf217ac9@linux-foundation.org> <2023070509-undertow-pulverize-5adc@gregkh> From: "Linux regression tracking (Thorsten Leemhuis)" In-Reply-To: <2023070509-undertow-pulverize-5adc@gregkh> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1688547135;c9955e32; X-HE-SMSGID: 1qGyF1-0002O0-Fp X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Linux regressions mailing list Cc: Jacob Young , Linux regressions mailing list , Greg KH , Linux Kernel Mailing List , Linux Memory Management , Bagas Sanjaya , Laurent Dufour , Linux PowerPC , Linux ARM Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 05.07.23 09:08, Greg KH wrote: > On Tue, Jul 04, 2023 at 01:22:54PM -0700, Suren Baghdasaryan wrote: >> On Tue, Jul 4, 2023 at 9:18 AM Andrew Morton wrote: >>> On Tue, 4 Jul 2023 09:00:19 +0100 Greg KH wrote: >>>>>>>> Thanks! I'll investigate this later today. After discussing with >>>>>>>> Andrew, we would like to disable CONFIG_PER_VMA_LOCK by default until >>>>>>>> the issue is fixed. I'll post a patch shortly. >>>>>>> >>>>>>> Posted at: https://lore.kernel.org/all/20230703182150.2193578-1-surenb@google.com/ >>>>>> >>>>>> As that change fixes something in 6.4, why not cc: stable on it as well? >>>>> >>>>> Sorry, I thought since per-VMA locks were introduced in 6.4 and this >>>>> patch is fixing 6.4 I didn't need to send it to stable for older >>>>> versions. Did I miss something? >>>> >>>> 6.4.y is a stable kernel tree right now, so yes, it needs to be included >>>> there :) >>> >>> I'm in wait-a-few-days-mode on this. To see if we have a backportable >>> fix rather than disabling the feature in -stable. Andrew, how long will you remain in "wait-a-few-days-mode"? Given what Greg said below and that we already had three reports I know of I'd prefer if we could fix this rather sooner than later in mainline -- especially as Arch Linux and openSUSE Tumbleweed likely have switched to 6.4.y already or will do so soon. >> Ok, I think we have a fix posted at [2] and it's cleanly applies to >> 6.4.y stable branch as well. However fork() performance might slightly >> regress, therefore disabling per-VMA locks by default for now seems to >> be preferable even with this fix (see discussion at >> https://lore.kernel.org/all/54cd9ffb-8f4b-003f-c2d6-3b6b0d2cb7d9@google.com/). >> IOW, both [1] and [2] should be applied to 6.4.y stable. Both apply >> cleanly and I CC'ed stable on [2]. Greg, should I send [1] separately >> to stable@vger? > > We can't do anything for stable until it lands in Linus's tree, so if > you didn't happen to have the stable@ tag in the patch, just email us > the git SHA1 and I can pick it up that way. > > thanks, > > greg k-h Ciao, Thorsten