From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1449503-1526944232-2-10803793067230069626 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.248, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: cc='ISO-8859-1', plain='ISO-8859-1' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1526944232; b=gBor1yq9uY767XmVlbLnZJqaCC8l2GTsbGQ1h3/w1xEnN2/ZV/ 1AhW/lANvS/VlPCyuCeJ/3UiLsOK39RZgg+zWvJMEW/GFrdK1PwQYovbiCdADzA8 e21oO93fXB5mQNF2xGM+KKbiPrDD871o/9aLMgiq2MT3FwOigr1Wwi6RB0Sv4Kdd cjQo6IoHgyZJJSaoeNuqHKT7+lOO7NZql19JH9n8rwfVQfMSqNn+MzlkUbdFE+Dp h/VX2X/6U4l89aTlxGTreEIYn9HlCQSoPS8PO2dGwFyurKWzZhXTw+M7zTC/76ob ZOpk3LRXldvFnEGyXOIUQL+s6HrvWG2Qzdlw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :in-reply-to:references:mime-version:content-type :content-transfer-encoding:sender:list-id; s=fm2; t=1526944232; bh=xSqpWsOSj7tyJu9vJQxmd1tB0wd/zxJq6G14L4Q5uuQ=; b=c3dsLDZlsEZk XliC8weY4Zf8IMz0SbJ3vW1HfZ/RYByPZPT+71oYasp86aRIq9PegTyRqv0IlZdD e9qjwXYW90hy6I3ZkDBVz9nCPXI/1q/SmrbYBs9C8rr/YwPxlX1D5Vzyb0KBA8xD FQjvh50Y+XhIMhRE0qjv1SPqL+/ItSO0Fyh6p4Zyhb/mDlOs8sA2Ii5AUbvS/wxj YoP64l+g6WhQNjQ5BdkTfoUygDXsrQltcqJT3kybAnxiAj3/oW0Txt95WgBGxO8o CGpSHH7BRP0COrZiMR/wB5A6c7HyOAJ9VletjYiBG39o0vYXQQRh+9LxMLZHGT2u iTzwOovV0g== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linux-foundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linux-foundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linux-foundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linux-foundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfKK8cmbQAj0VkPjBzuJZAHyGSI13ZSozHbTsCQFHroEFyogu7PowLeTa1EG7DDRZyBOUX9hjbyzEz8cQ3LOfJs4LxB/4mOFIQ947GbSG1kinZM9CdF6B wKDwIDg/JAoKW6/uPmYfeaZDm+0nPoEJ4lrmXEtN77upucthDhcMvmzABqMqOqsPt6z/aTyp02okGsahamZbpru3KzOjx8Pc0tzPQi5WA6HZMLGNawkniC2h X-CM-Analysis: v=2.3 cv=NPP7BXyg c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=8nJEP1OIZ-IA:10 a=VUJBJC2UJ8kA:10 a=QyXUC8HyAAAA:8 a=VwQbUJbxAAAA:8 a=20KFwNOVAAAA:8 a=gXLdhW2jAAAA:8 a=0h-UnUqaR0D1f81tj1UA:9 a=wPNLvfGTeEIA:10 a=AjGcO6oz07-iQ99wixmX:22 a=Dn9eIPSr_RzuO0KTJioD:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751019AbeEUXK3 convert rfc822-to-8bit (ORCPT ); Mon, 21 May 2018 19:10:29 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:52220 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbeEUXK3 (ORCPT ); Mon, 21 May 2018 19:10:29 -0400 Date: Mon, 21 May 2018 16:10:26 -0700 From: Andrew Morton To: Dan Williams Cc: stable@vger.kernel.org, Christoph Hellwig , =?ISO-8859-1?Q?J=E9r=F4me?= Glisse , Logan Gunthorpe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/5] mm, devm_memremap_pages: handle errors allocating final devres action Message-Id: <20180521161026.709d5f2876e44f151da3d179@linux-foundation.org> In-Reply-To: <152694212460.5484.13180030631810166467.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152694211402.5484.2277538346144115181.stgit@dwillia2-desk3.amr.corp.intel.com> <152694212460.5484.13180030631810166467.stgit@dwillia2-desk3.amr.corp.intel.com> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Mon, 21 May 2018 15:35:24 -0700 Dan Williams wrote: > The last step before devm_memremap_pages() returns success is to > allocate a release action to tear the entire setup down. However, the > result from devm_add_action() is not checked. > > Checking the error also means that we need to handle the fact that the > percpu_ref may not be killed by the time devm_memremap_pages_release() > runs. Add a new state flag for this case. > > Cc: > Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...") > Cc: Christoph Hellwig > Cc: "Jérôme Glisse" > Cc: Logan Gunthorpe > Signed-off-by: Dan Williams Why the cc:stable? The changelog doesn't describe the end-user-visible impact of the bug (it always should, for this reason). AFAICT we only go wrong when a small GFP_KERNEL allocation fails (basically never happens), with undescribed results :(