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=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 C735EC0044C for ; Thu, 1 Nov 2018 10:30:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 71A762081B for ; Thu, 1 Nov 2018 10:30:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 71A762081B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728153AbeKATdN (ORCPT ); Thu, 1 Nov 2018 15:33:13 -0400 Received: from mx2.suse.de ([195.135.220.15]:58558 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727453AbeKATdN (ORCPT ); Thu, 1 Nov 2018 15:33:13 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 26389ADD3; Thu, 1 Nov 2018 10:30:51 +0000 (UTC) Date: Thu, 1 Nov 2018 11:30:50 +0100 From: Michal Hocko To: =?utf-8?B?56a56Iif6ZSu?= Cc: akpm@linux-foundation.org, rientjes@google.com, kirill.shutemov@linux.intel.com, aarcange@redhat.com, penguin-kernel@i-love.sakura.ne.jp, guro@fb.com, yang.s@alibaba-inc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wind Yu Subject: Re: [PATCH v15 1/2] Reorganize the oom report in dump_header Message-ID: <20181101103050.GG23921@dhcp22.suse.cz> References: <1538226387-16600-1-git-send-email-ufo19890607@gmail.com> <20181031135049.GO32673@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 01-11-18 18:09:39, 禹舟键 wrote: > Hi Michal > The null pointer is possible when calling the dump_header, this bug was > detected by LKP. Below is the context 3 months ago. Yeah I remember it was 0day report but I coundn't find it in my email archive. Do you happen to have a message-id? Anyway if (__ratelimit(&oom_rs)) dump_header(oc, p); + if (oc) + dump_oom_summary(oc, victim); Clearly cannot solve any NULL ptr because oc is never NULL unless I am missing something terribly. -- Michal Hocko SUSE Labs