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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, 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 0A378C04AB1 for ; Thu, 9 May 2019 10:36:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBE5320644 for ; Thu, 9 May 2019 10:36:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="q7BtAowi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726600AbfEIKg2 (ORCPT ); Thu, 9 May 2019 06:36:28 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:43480 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725869AbfEIKg1 (ORCPT ); Thu, 9 May 2019 06:36:27 -0400 Received: by mail-pl1-f195.google.com with SMTP id n8so941460plp.10 for ; Thu, 09 May 2019 03:36:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=bHZmeHYkLEL+rg5709BsrdM/vHK9Q/g3rJek3ZFgWD0=; b=q7BtAowibgLk5SBQD+sjAALwhMqRAvExXByjUTtprxBc4hByjteLgSgtKSBYuFyfjN gAqJEeMXIUqpZwwwV+ZACaplr/xdE44xziW714X7OKam3EC3ykl3cN05OcO59vR9K73L U1WIeg1bjIa2x1//M1IN0iGvWSNS+5XzlMU1Ul+Z875GnYAiP9Ej/pN9JYNeDJqSdb8H wzt4yS/lHCFgn2AjkQC5r3koZGPosGWn8LqVaXORVfziPEpuwTtjAEzwcIV5bxtXb6AM sE6YLsjyMB4k+HuaQL/hKtXWC0gPGkcpdwE4nTAbihWssi5mkNdh94YF/huCr8W4vld6 IIuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=bHZmeHYkLEL+rg5709BsrdM/vHK9Q/g3rJek3ZFgWD0=; b=Tvb+FWkfAXLt4ovhNaUSqpbEXeblbFeyFfFSYtpT/3G3bPuTw384sGaAFbRVX8bLbg BYWbMU6iGFUiZi1JxrE16KRNCHA0kVULqzGvtrDf9S3ybgYicdvaUXYN/J6O50cZA97H 4rhpjJL3QnqMgqTKFe6jVPHDhAaEJM/H4i0NOCBEAEBEQ2dvoWPRRO2UH1c8MOhpoGHv ZC8bzxY91yqu6n3ieFBg+/qAnI9e55SnbsWOKc+oyycuQ4MArvotAHGv1hK1R8uRYFwQ OAeO8BJyfmtX42vyOw7SCbVlcpi/V75YdTSsDRmkTntJ5Gxh4A0Pap5EZ6ijSVyHb8f7 x6Gw== X-Gm-Message-State: APjAAAU6i/KpqisSBw1DzN9HAzA9xTa1AIH/yK/j+W/1D2beOmFzZgKE BA8GvyGUVCSTtEWmje3zLYc= X-Google-Smtp-Source: APXvYqzgoQjjox51KD2bI0JzcBAKJmhMOmojw6RxQz0qp4nGKq9DFDAJq4wvcGExnmd//CayYmeoAQ== X-Received: by 2002:a17:902:694c:: with SMTP id k12mr3815704plt.149.1557398186919; Thu, 09 May 2019 03:36:26 -0700 (PDT) Received: from localhost ([39.7.47.21]) by smtp.gmail.com with ESMTPSA id h189sm2727625pfc.125.2019.05.09.03.36.25 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 09 May 2019 03:36:26 -0700 (PDT) Date: Thu, 9 May 2019 19:36:23 +0900 From: Sergey Senozhatsky To: Tetsuo Handa Cc: Sergey Senozhatsky , Dmitry Vyukov , Sergey Senozhatsky , Petr Mladek , LKML , syzkaller Subject: Re: [syzbot? printk?] no WARN_ON() messages printed before "Kernel panic - not syncing: panic_on_warn set ..." Message-ID: <20190509103623.GA3369@jagdpanzerIV> References: <20190318125019.GA2686@tigerII.localdomain> <20190318140937.GA29374@tigerII.localdomain> <20190319123500.GA18754@tigerII.localdomain> <127c9c3b-f878-174f-7065-66dc50fcabcf@i-love.sakura.ne.jp> <20190509095823.GA23572@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (05/09/19 19:26), Tetsuo Handa wrote: > >> By the way, recently we are hitting false positives caused by "WARNING:" > >> string from not WARN() messages but plain printk() messages (e.g. > >> > >> https://syzkaller.appspot.com/bug?id=31bdef63e48688854fde93e6edf390922b70f8a4 > >> https://syzkaller.appspot.com/bug?id=faae4720a75cadb8cd0dbda5c4d3542228d37340 > >> > >> ) and we need to avoid emitting "WARNING:" string from plain printk() messages > >> during fuzzing testing. I guess we want to add something like > >> CONFIG_DEBUG_AID_FOR_SYZBOT to all kernels in order to mask such string... > > > > I thought that we have MSG_FORMAT_SYSLOG exactly for things like these, > > so you can look at actual message level <%d> and then decide if it's a > > warning or a false alarm. > > Since syzbot needs to use console output, message level is not available. Sorry, not following. MSG_FORMAT_SYSLOG should add message level to console output. Booting the kernel with console_msg_format=syslog will change msg_print_text() behaviour, and you'll get on your serial console messages in [print_time][print_caller] message text\n format. Does this work for you? -ss