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 D1407C001B3 for ; Wed, 5 Jul 2023 07:09:57 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=tKdIALsR; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4QwrQD1SBcz3bpt for ; Wed, 5 Jul 2023 17:09:56 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=tKdIALsR; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linuxfoundation.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=gregkh@linuxfoundation.org; receiver=lists.ozlabs.org) Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QwrPG102Zz300t for ; Wed, 5 Jul 2023 17:09:06 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 405A961453; Wed, 5 Jul 2023 07:09:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57875C433C7; Wed, 5 Jul 2023 07:09:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1688540940; bh=KNHJu+0CLU4ZCQdLgEFri5D+Z9BwIrdluwuvuUeNttE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tKdIALsR0dMkHa9DJuKzvIPN6d8h9dFfEniOOt9bWgEKNcQIdf7any+sOkoPLEKea +95s2KQ452fHNF4mzK3LiP0iF8hrCJ186zokGs38t/pxGUAu4cT3Fhxu8f4UEm1j6P LCmtLDw3WijgFusqsM7zA87m4MVC7ID+D/hmFgPI= Date: Wed, 5 Jul 2023 08:08:58 +0100 From: Greg KH To: Suren Baghdasaryan Subject: Re: Fwd: Memory corruption in multithreaded user space program while calling fork Message-ID: <2023070509-undertow-pulverize-5adc@gregkh> References: <5c7455db-4ed8-b54f-e2d5-d2811908123d@leemhuis.info> <2023070359-evasive-regroup-f3b8@gregkh> <2023070453-plod-swipe-cfbf@gregkh> <20230704091808.aa2ed3c11a5351d9bf217ac9@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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: , Cc: Jacob Young , Linux regressions mailing list , Linux Kernel Mailing List , Linux Memory Management , Bagas Sanjaya , Andrew Morton , Laurent Dufour , Linux PowerPC , Linux ARM Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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. > > 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