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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F5F9C3F6B0 for ; Tue, 23 Aug 2022 19:26:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231881AbiHWT0Y (ORCPT ); Tue, 23 Aug 2022 15:26:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231635AbiHWT0F (ORCPT ); Tue, 23 Aug 2022 15:26:05 -0400 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CF5813DBA4; Tue, 23 Aug 2022 11:12:15 -0700 (PDT) Received: by mail-pj1-x102e.google.com with SMTP id r14-20020a17090a4dce00b001faa76931beso18027129pjl.1; Tue, 23 Aug 2022 11:12:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :from:to:cc; bh=w6Y6IjnB/7GXBq23acV5syGhC64cBXwxU4OuyhZd8CQ=; b=IaP7cFBpGcNi3/hhyxFebsnvxJsMy54QTl7EkiYLgJCebOU1/sY6ya+8Jj7s9gc5zJ m96Jd0oUB9ii7t+kjHWa0AYbqnMm5HXw9j51y4fR0GTSjpmruV6mcpR1pH2bNOo7Eh9J 1+m93Urk2CcVD+dQQvvEOgbAJqBAErrzKbUqYPqCFKfnC9JQXmYBIYNVyoJZVAbB6LO2 5fvVxUuzhxJTX2ZCcqC78LL+jJzs7uc6dP6iwGIMRwK76xIIh3W8VDmSaT8p0QyXPYzZ WxnHrnIHJWsGCnNde81/z4kR2sB4563gvDfugD+mJi4dvRasMOT9T+3eMQq+GiKhQ+Kp xOkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :x-gm-message-state:from:to:cc; bh=w6Y6IjnB/7GXBq23acV5syGhC64cBXwxU4OuyhZd8CQ=; b=bY7IFJWo7EOkjQAhMK4xYCvW/Fi12t7Wl7B5zuFElR4MXyNlSqrcrNCxry+TEVvLW/ MNrGKzJCd/NxPrwy1uZzN6Zez4KBNyor1WAxbIlqZxqrMvuAiI6I2pEmkGg6SYPZBkQC +BEqSlDVH8YHoyzUNDCWp0i+fvFYlMZpl3NWI48E6YO6N5ck1qqPuh2iYb9rMAlo92kM 2Jq+PhrF3W9nBe4ca+72QGQR948pfGXbJceBvLuQWGQyH473CkhrMun4aSdFnaUzjQq/ MXiK3/UNaYWVsbMBrUP2wI7BsDZpz1TIquRYSbBrcg62FFDrBY8/PA0oHsxauor3X3+C 2IOQ== X-Gm-Message-State: ACgBeo2ML8rxxKuFNqRishtP5+5BMWieVKOAEDXTZe8kmtXxxJ5ajs+L 9p97UkG7Fxp+S7SLkKR/Svk= X-Google-Smtp-Source: AA6agR5OMzXPWSEia1ICuDVxlmd5kDRtjxcPzDjzeIQnJSzFFes7fZNXVlt3vyVCqQga04y7fD0YmQ== X-Received: by 2002:a17:902:d712:b0:172:e2f8:7f02 with SMTP id w18-20020a170902d71200b00172e2f87f02mr11541384ply.26.1661278334213; Tue, 23 Aug 2022 11:12:14 -0700 (PDT) Received: from localhost ([2620:10d:c090:400::5:90fa]) by smtp.gmail.com with ESMTPSA id l9-20020a170902f68900b0016be96e07d1sm10712480plg.121.2022.08.23.11.12.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Aug 2022 11:12:13 -0700 (PDT) Sender: Tejun Heo Date: Tue, 23 Aug 2022 08:12:12 -1000 From: Tejun Heo To: Jing-Ting Wu Cc: Michal =?iso-8859-1?Q?Koutn=FD?= , Zefan Li , Johannes Weiner , Matthias Brugger , Jonathan.JMChen@mediatek.com, Lixiong.Liu@mediatek.com, wsd_upstream@mediatek.com, Wenju.Xu@mediatek.com, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: Re: [PATCH 1/1] cgroup: Fix race condition at rebind_subsystems() Message-ID: References: <20220823054148.29346-1-Jing-Ting.Wu@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220823054148.29346-1-Jing-Ting.Wu@mediatek.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 23, 2022 at 01:41:46PM +0800, Jing-Ting Wu wrote: > Root cause: > The rebind_subsystems() is no lock held when move css object from A > list to B list,then let B's head be treated as css node at > list_for_each_entry_rcu(). > > Solution: > Add grace period before invalidating the removed rstat_css_node. > > Reported-by: Jing-Ting Wu > Suggested-by: Michal Koutný > Signed-off-by: Jing-Ting Wu > Tested-by: Jing-Ting Wu > Link: https://lore.kernel.org/linux-arm-kernel/d8f0bc5e2fb6ed259f9334c83279b4c011283c41.camel@mediatek.com/T/ Applied to cgroup/for-6.0-fixes w/ stable tag added. Thanks. -- tejun