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=-8.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 7C2EEC43381 for ; Sat, 16 Mar 2019 15:10:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 49C9D218E0 for ; Sat, 16 Mar 2019 15:10:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Vd2UZ7IC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727146AbfCPPK2 (ORCPT ); Sat, 16 Mar 2019 11:10:28 -0400 Received: from mail-it1-f193.google.com ([209.85.166.193]:39579 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726064AbfCPPK2 (ORCPT ); Sat, 16 Mar 2019 11:10:28 -0400 Received: by mail-it1-f193.google.com with SMTP id l15so15403709iti.4 for ; Sat, 16 Mar 2019 08:10:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JkTDSbQzw2+olZOctVQP5qL+c8FHI1uVKJOTh59K2fg=; b=Vd2UZ7ICAZJeelXJO0a24gBxjI/N1dvEETUO2K2AAsvinVoE5NgPhmN/gUtlG8sY/S ZByZLfm6/3s8VUgHAGJxzphro7G2uh1zR+B4O/cPGNAq4WiGf7V+kGERxcSQF0Eci16q PAfoVIB4dT/cZt9+nxu8JK3rjC5OjFCqbqOtV+gtUWH6T1+Ei7reOexdmdTSf7mGU0XG EzzWJi4KTuZiGfcmX3pO7OwuGxcHwSpotbroczSFNVrFI60vjl+91EXM0vep//ZQp9lA xL6Z5Yyt0O5VTge0x4f4TtWFFGFGW6+ubiZX4aTNx+W6PVgh4O1xEuCMYqSD5R7OE7Qf WbPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JkTDSbQzw2+olZOctVQP5qL+c8FHI1uVKJOTh59K2fg=; b=NajhiNDeCqsiOdWwmF7oGvoYTL0ZGRgfka5Pg2sKsMm2NMGspyWrFWdg5cpcBGfp43 MsR097PyXKunEPneYcPjD/1TfZpK4+c6Ah5LGw2+fB0KrbFwOBzlIWX56Sdo+pqjkdIa OnLzHW7LWXJndGAT1wHIXT4vdaGcqFmpyxNHKpLQ/dLjCn2Z4Bv4/4YDNBkuHtgheW7s 2bU1mDx8m3xEvEQoqXLKdz2Rp3RPFuyim2iedHlTI5GZlX8drDDmRAY85JAIUsYihTef 85wRL1n3tzcFHNgfNItK46w5Vbi2g1pNVYLvj5eKq7aNGDihoR8GJGh32auFW4fHTFxH XFTA== X-Gm-Message-State: APjAAAU+iWveMg3eyI36FdGBTiOeDL9TR7kpQ9u0Yl/AoZ5sWf78djpu 5gUkvoh4S3vDqlxPe3DbiorG/A5T+FQ0JeE3Y3sMfw== X-Google-Smtp-Source: APXvYqzMYzWAgmneuO87STKTvpCpiLzed682ROwOpKqYJ2NtjQpKxTvQ5sHk2uCSAof8lSey8xGHQGbOSqP+f8Pvcqw= X-Received: by 2002:a24:674a:: with SMTP id u71mr5552481itc.12.1552749027098; Sat, 16 Mar 2019 08:10:27 -0700 (PDT) MIME-Version: 1.0 References: <0a0d282b-6757-5f42-b888-ef52b040aaa1@i-love.sakura.ne.jp> <20190316141410.GA18654@tigerII.localdomain> <647012f4-c221-addf-51ab-586014e8f435@i-love.sakura.ne.jp> <2a48dee7-b649-65a4-be5d-8b3374013cee@i-love.sakura.ne.jp> In-Reply-To: <2a48dee7-b649-65a4-be5d-8b3374013cee@i-love.sakura.ne.jp> From: Dmitry Vyukov Date: Sat, 16 Mar 2019 16:10:15 +0100 Message-ID: Subject: Re: [syzbot? printk?] no WARN_ON() messages printed before "Kernel panic - not syncing: panic_on_warn set ..." To: Tetsuo Handa Cc: Sergey Senozhatsky , Petr Mladek , Sergey Senozhatsky , LKML , syzkaller Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 16, 2019 at 4:02 PM Tetsuo Handa wrote: > > On 2019/03/16 23:57, Dmitry Vyukov wrote: > > On Sat, Mar 16, 2019 at 3:53 PM Tetsuo Handa > > wrote: > >> > >> On 2019/03/16 23:16, Dmitry Vyukov wrote: > >>>>> Maybe try running with "ignore_loglevel" kernel command line option added? > >>>> > >>>> Right, that's something I would expect 0-day and syzkaller to do. > >>> > >>> to double-check: enabling this won't lead to verbose/debug level of logging? > >>> > >> > >> I don't know what "verbose/debug level" means. But enabling this option causes > >> KERN_{EMERG,ALERT,CRIT,ERR,WARNING,NOTICE,INFO,DEBUG} be printed equally. > >> > >> "ignore loglevel setting (prints all kernel messages to the console)" > >> > >> static bool suppress_message_printing(int level) > >> { > >> return (level >= console_loglevel && !ignore_loglevel); > >> } > > > > Then I don't think it's suitable: there will be too much output. > > > > Then, we need to find what test is changing console_loglevel. > Maybe add debug BUG_ON() in linux-next.git using CONFIG_DEBUG_AID_FOR_SYZBOT ? Is there a single place to catch this? I could run syzkaller locally first with the check.