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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B788C43387 for ; Fri, 11 Jan 2019 00:23:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C31F206B7 for ; Fri, 11 Jan 2019 00:23:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728125AbfAKAXv (ORCPT ); Thu, 10 Jan 2019 19:23:51 -0500 Received: from mga14.intel.com ([192.55.52.115]:38525 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727545AbfAKAXu (ORCPT ); Thu, 10 Jan 2019 19:23:50 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Jan 2019 16:23:50 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,463,1539673200"; d="scan'208";a="134873707" Received: from shao2-debian.sh.intel.com (HELO [10.239.13.6]) ([10.239.13.6]) by fmsmga004.fm.intel.com with ESMTP; 10 Jan 2019 16:23:48 -0800 Subject: Re: [kbuild-all] [PATCH 2/2] memcg: do not report racy no-eligible OOM tasks To: Michal Hocko , kbuild test robot Cc: Tetsuo Handa , LKML , linux-mm@kvack.org, kbuild-all@01.org, Johannes Weiner , Andrew Morton References: <20190107143802.16847-3-mhocko@kernel.org> <201901081642.Q6tXklr0%fengguang.wu@intel.com> <20190108093959.GQ31793@dhcp22.suse.cz> From: Rong Chen Message-ID: Date: Fri, 11 Jan 2019 08:23:57 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20190108093959.GQ31793@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/08/2019 05:39 PM, Michal Hocko wrote: > On Tue 08-01-19 16:35:42, kbuild test robot wrote: > [...] >> All warnings (new ones prefixed by >>): >> >> include/linux/rcupdate.h:659:9: warning: context imbalance in 'find_lock_task_mm' - wrong count at exit >> include/linux/sched/mm.h:141:37: warning: dereference of noderef expression >> mm/oom_kill.c:225:28: warning: context imbalance in 'oom_badness' - unexpected unlock >> mm/oom_kill.c:406:9: warning: context imbalance in 'dump_tasks' - different lock contexts for basic block >>>> mm/oom_kill.c:918:17: warning: context imbalance in '__oom_kill_process' - unexpected unlock > What exactly does this warning say? I do not see anything wrong about > the code. find_lock_task_mm returns a locked task when t != NULL and > mark_oom_victim doesn't do anything about the locking. Am I missing > something or the warning is just confused? Thanks for your reply. It looks like a false positive. We'll look into it. Best Regards, Rong Chen > > [...] >> 00508538 Michal Hocko 2019-01-07 915 t = find_lock_task_mm(p); >> 00508538 Michal Hocko 2019-01-07 916 if (!t) >> 00508538 Michal Hocko 2019-01-07 917 continue; >> 00508538 Michal Hocko 2019-01-07 @918 mark_oom_victim(t); >> 00508538 Michal Hocko 2019-01-07 919 task_unlock(t); >> 647f2bdf David Rientjes 2012-03-21 920 }