From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2007354-1523975811-2-11071709842524399713 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, RCVD_IN_DNSWL_NONE -0.0001, SPF_HELO_PASS -0.001, SPF_PASS -0.001, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='104.47.37.100', Host='mail-cys01nam02on0100.outbound.protection.outlook.com', Country='US', FromHeader='com', MailFrom='com', XOriginatingCountry='US' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: Alexander.Levin@microsoft.com ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1523975809; b=P/36ZRtc7h2Nk+ytdj3Ix0BzxZ9iPW5Vg9CmA88IBnwCyWxmsd R0IF/XqmoxbDYiuZ1okQpqSzGC73sVqrrEcatKpYhjmFqU5k01LVN9MbW7fR5GVv WhQemuE8zqdgp5Kvb/M4+kKs8Lwl+cRVC/wioI3EOVSt20fxA4MPM1+SAdsjXFyY /UrFUPf/PdBXooNhNDr0+j0qDjWDqI4FgYtXMYtu+f0i5NMAVnY2dHYVK8v64cxm YxiFc4FUiphXmMlAmg+FaKV5gNCzw7m8sKFlt1FIaFehoAqjUoFaZzowI7WOEmgU ZlycdWHcqERfVxgIRt8emc98N0D/l6MASQQw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :references:in-reply-to:content-type:content-id :content-transfer-encoding:mime-version; s=fm2; t=1523975809; bh=pK1R4FGKOa0937aMjDix6wABn+3OQ9VlRRC02xHaoAI=; b=TtZa5QUJg+yh /TZamgEkea6kiKehRBd8xHF87rZ+EjD3w5rl0ieDUP5PiQtYOUNxAloXlxJqVpZG asb1/w1JzL8+pF+JTnxNjFahBDzCT95yphoLIAR0YSgLqeVPi/NFtPlcTyUmbPkv m29ymSdAl39QQ5nFdub6sVitFzx7O159IfcpkhhwRgU8OUVqEkBzJxz97ExgaXln 6U8ezVBPOyBp0EOhtFNhvpSZ8kbYxBLklnkqnyuTjF5JyPj76svAmfNYRdQ8z2Au Xj6lsni5AZDfeMf17Y86frrSSLpDRxCvP6Ws90qkvHzs2DQMrpKqSTv1APKS7dfV 90vx4gzr4A== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=microsoft.com header.i=@microsoft.com header.b=TiKwxMYK x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=selector1; dmarc=pass (p=reject,d=none) header.from=microsoft.com; iprev=pass policy.iprev=104.47.37.100 (mail-cys01nam02on0100.outbound.protection.outlook.com); spf=pass smtp.mailfrom=Alexander.Levin@microsoft.com smtp.helo=NAM02-CY1-obe.outbound.protection.outlook.com; x-aligned-from=pass (Address match); x-cm=none score=0; x-ptr=fail x-ptr-helo=NAM02-CY1-obe.outbound.protection.outlook.com x-ptr-lookup=mail-cys01nam02on0100.outbound.protection.outlook.com; x-return-mx=pass smtp.domain=microsoft.com smtp.result=pass smtp_is_org_domain=yes header.domain=microsoft.com header.result=pass header_is_org_domain=yes; x-tls=pass version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128; x-vs=clean score=-100 state=0 Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=microsoft.com header.i=@microsoft.com header.b=TiKwxMYK x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=selector1; dmarc=pass (p=reject,d=none) header.from=microsoft.com; iprev=pass policy.iprev=104.47.37.100 (mail-cys01nam02on0100.outbound.protection.outlook.com); spf=pass smtp.mailfrom=Alexander.Levin@microsoft.com smtp.helo=NAM02-CY1-obe.outbound.protection.outlook.com; x-aligned-from=pass (Address match); x-cm=none score=0; x-ptr=fail x-ptr-helo=NAM02-CY1-obe.outbound.protection.outlook.com x-ptr-lookup=mail-cys01nam02on0100.outbound.protection.outlook.com; x-return-mx=pass smtp.domain=microsoft.com smtp.result=pass smtp_is_org_domain=yes header.domain=microsoft.com header.result=pass header_is_org_domain=yes; x-tls=pass version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfMHWvU7lmGkCKDHroeMIApoccbYlWQhoNzHvckr88wWt02Bef11t4cfr/w6lYElFfnpCjp+66ouqOnSdezjiYpmHzNLoYLFt51V9uLt7QI7cvRk0v01Q POXpyPBdio1QrWO3kIFeJc0wB4l7TQBgdMVYx+yPNQVkvT/u0Fy81Z4SRGTckOi1+RIt1Ue5vQqKz/W/yoCiGvvrwMF5PoHICxixzWMz/52hOiuTR/RSN/MA YE9uu1s/uVWQ/P8YJcuD7Q== X-CM-Analysis: v=2.3 cv=FKU1Odgs c=1 sm=1 tr=0 a=ENVodV5vEat0xvru/pPgWQ==:117 a=wRwT6uffUbIA:10 a=t_PdEiP4ckcA:10 a=F7qjIGpQ-GgA:10 a=kj9zAlcOel0A:10 a=xqWC_Br6kY4A:10 a=Kd1tUaAdevIA:10 a=Lf-vpJhqX20A:10 a=VwQbUJbxAAAA:8 a=D19gQVrFAAAA:8 a=B9MCPAVda64oPgiEUu8A:9 a=CjuIK1q_8ugA:10 a=AjGcO6oz07-iQ99wixmX:22 a=W4TVW4IDbPiebHqcZpNg:22 X-ME-CMScore: 0 X-ME-CMCategory: none From: Sasha Levin To: Michal Hocko CC: Petr Mladek , Greg KH , Pavel Machek , Steven Rostedt , Linus Torvalds , "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "linux-mm@kvack.org" , Cong Wang , Dave Hansen , Johannes Weiner , Mel Gorman , Vlastimil Babka , Peter Zijlstra , Jan Kara , Mathieu Desnoyers , Tetsuo Handa , Byungchul Park , Tejun Heo Subject: Re: [PATCH AUTOSEL for 4.14 015/161] printk: Add console owner and waiter logic to load balance console writes Thread-Topic: [PATCH AUTOSEL for 4.14 015/161] printk: Add console owner and waiter logic to load balance console writes Thread-Index: AQHTz5h7IvK2v80d0k6VVqDoPwJEM6P4GK8AgAnYKwCAAX5DAIAAHfKAgAADdYCAAAWWgIAABF0AgAACQQCAAAJjAIAAAleAgAAEfoCAAAGdAIAAAgMAgAEp94CAABt1AIAABtkAgAAOAICAAAwWAIAAA+OA Date: Tue, 17 Apr 2018 14:36:44 +0000 Message-ID: <20180417143641.GV2341@sasha-vm> References: <20180416122244.146aec48@gandalf.local.home> <20180416163107.GC2341@sasha-vm> <20180416124711.048f1858@gandalf.local.home> <20180416165258.GH2341@sasha-vm> <20180416170010.GA11034@amd> <20180417104637.GD8445@kroah.com> <20180417122454.rwkwpsfvyhpzvvx3@pathway.suse.cz> <20180417124924.GE17484@dhcp22.suse.cz> <20180417133931.GS2341@sasha-vm> <20180417142246.GH17484@dhcp22.suse.cz> In-Reply-To: <20180417142246.GH17484@dhcp22.suse.cz> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [52.168.54.252] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;DM5PR2101MB0728;7:AetOvqyzicx4qimOon94yKmvsAh16jiIupwj9g83Un0KuPH7n5ES6F6E3Sghdrz1TcRtER1IIGKt3BVGQ1KqcBUI15347ym1YwST9KeTYYHEZR9QcBzZj0JUq/YrrWc7lgwR5es22AhXCE6A7SKnEP/EpA2QfbERg2R3qF3HCkM6VESsj3Ljq2h5iKCaAph3KnuZ279Qf+TNgLc8Cn3PYkLSGHPfC+G4hrpP7rKn5IOhfHIJfkmsIRsHXArEw4Xb;20:gD+UeHzWER1BxXRad9DGtUhGNwkX7q5MHQCcosHFzf4EcMLpAdUqriJVh7Gr8zBKEQu1UoEofyEBRKenAKO7lOVbog20H50/j6xrnumwKw0La33uGQc+0fWCx7SnUGUEElUt44hpcvnV4kZmrAMa6t2wp8pMIAgTtF7R3zIAshI= x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(48565401081)(4534165)(4627221)(201703031133081)(201702281549075)(5600026)(2017052603328)(7193020);SRVR:DM5PR2101MB0728; x-ms-traffictypediagnostic: DM5PR2101MB0728: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Alexander.Levin@microsoft.com; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(84791874153150); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(61425038)(6040522)(2401047)(5005006)(8121501046)(10201501046)(93006095)(93001095)(3002001)(3231232)(944501359)(52105095)(6055026)(61426038)(61427038)(6041310)(20161123558120)(20161123564045)(20161123562045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123560045)(6072148)(201708071742011);SRVR:DM5PR2101MB0728;BCL:0;PCL:0;RULEID:;SRVR:DM5PR2101MB0728; x-forefront-prvs: 0645BEB7AA x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(7916004)(39380400002)(376002)(346002)(366004)(396003)(39860400002)(54534003)(189003)(199004)(377424004)(305945005)(6506007)(68736007)(316002)(2906002)(3280700002)(5660300001)(1076002)(59450400001)(105586002)(33896004)(446003)(11346002)(39060400002)(486006)(86362001)(86612001)(478600001)(10090500001)(4326008)(966005)(26005)(72206003)(476003)(10290500003)(97736004)(99286004)(25786009)(33716001)(186003)(8936002)(6246003)(6512007)(6436002)(81156014)(6306002)(14454004)(5250100002)(81166006)(9686003)(33656002)(2900100001)(229853002)(76176011)(7736002)(7416002)(93886005)(6916009)(3846002)(6116002)(54906003)(3660700001)(22452003)(106356001)(6486002)(102836004)(53936002)(66066001)(8676002)(217873001);DIR:OUT;SFP:1102;SCL:1;SRVR:DM5PR2101MB0728;H:DM5PR2101MB1032.namprd21.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; x-microsoft-antispam-message-info: zn3rkckoa6an7RZ8V8U0ssfL92uDbYP5BOYHnk0hDDrFYLBr24OjL/Jx0v+7V0hOeJcZqMMPZIKCU0lrQhbNMQe60NFqHP9diczSev8sLFQQTySz6PyIwNQ2ghgcqBoAVrbSUXKHQUlMjiqBO93sSk9Gpn0vjncBuwJCx7ARO2ooe4J2RiZ454ItS4keMfNx spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Office365-Filtering-Correlation-Id: 22453e05-83c5-4878-0f28-08d5a470a48d X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 22453e05-83c5-4878-0f28-08d5a470a48d X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Apr 2018 14:36:44.5512 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB0728 X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Tue, Apr 17, 2018 at 04:22:46PM +0200, Michal Hocko wrote: >On Tue 17-04-18 13:39:33, Sasha Levin wrote: >[...] >> But mm/ commits don't come only from these people. Here's a concrete >> example we can discuss: >> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi= t/?id=3Dc61611f70958d86f659bca25c02ae69413747a8d > >I would be really careful. Because that reqiures to audit all callers to >be compliant with the change. This is just _too_ easy to backport >without noticing a failure. Now consider the other side. Is there any >real bug report backing this? This behavior was like that for quite some >time but I do not remember any actual bug report and the changelog >doesn't mention one either. It is about theoretical problem. https://lkml.org/lkml/2018/3/19/430 There's even a fun little reproducer that allowed me to confirm it's an issue (at least) on 4.15. Heck, it might even qualify as a CVE. >So if this was to be merged to stable then the changelog should contain >a big fat warning about the existing users and how they should be >checked. So what I'm asking is why *wasn't* it sent to stable? Yes, it requires additional work backporting this, but what I'm saying is that this didn't happen at all. >Besides that I can see Reviewed-by: akpm and Andrew is usually very >careful about stable backports so there probably _was_ a reson to >exclude stable. >--=20 >Michal Hocko >SUSE Labs=