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 E5447C43381 for ; Sat, 16 Mar 2019 14:58:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E9AD218E0 for ; Sat, 16 Mar 2019 14:58:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ohI59Hp9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727103AbfCPO6B (ORCPT ); Sat, 16 Mar 2019 10:58:01 -0400 Received: from mail-it1-f194.google.com ([209.85.166.194]:34514 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726959AbfCPO6A (ORCPT ); Sat, 16 Mar 2019 10:58:00 -0400 Received: by mail-it1-f194.google.com with SMTP id l4so5947924ite.1 for ; Sat, 16 Mar 2019 07:58:00 -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=cqNuOcONm2jWu25it3fsvccpcGtkuXyVvZc3t7gminQ=; b=ohI59Hp9Xqa9mZzWhUUzp3wgphcKvo9b9v66irOMPpbSsgxHUK5yltufRlP769NHeS W0YOFcg5prs3MHdeMkRRKYSmmOwrKh1E90A3wJpM3UZh4jJ8bCtBY6TyEkVecLZEoVhG MUvCoAA0SExDiczWmtnECWHl+PYHsAFoSWcr7FaqWYLmixKRoqPjUQ/NO4TSk0p3LkrS gn3jy3pF0nKdMQxW7mqpE5XNoEgjShUptqOmW2p3GAtVBGZVu7kIblVJisCURB4Yc+1I ahVhGbf3lEEj5s3N+U1U+YbKdlPgNz2CBb8xUHrJuxzW59aHvYQvIot4+sVGZgekr/XQ tynQ== 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=cqNuOcONm2jWu25it3fsvccpcGtkuXyVvZc3t7gminQ=; b=ffqh/Eu4xYMH4/1F6vi9yo+WhkSrx80AQbt4gPAAhCGPRHNq+PSefbjk2U0E7RgZBm YMhdvMj8ZPi0meWf/+UIrhW69meSQWvCRd5bZLK2s4GKGTi5jwKKQDrnUELeVdxDp0BQ /0ydel/D6jLdh05u7ckpw79v4me17tZjExBmjoKZCMlgr+YEC3WScqhhP6SrlwZMUg7S 83b45eYlvk/n2QT6ZYQ/Gk+bpw+qQrK8PKneLkS+/iPqoMdIWUJRqD0IiWXDrtDmLNxU JDJqZlGQmyfM+QgVFS3vewNASTIHJr+UEekLZqFUj0vSfzqDdnOBQ93hNsE3r7XPm5cH Bwxg== X-Gm-Message-State: APjAAAVR6zvflUZKDThQzzsFOeBZNQyt22x2z/rrNDnhbEXkxS5LrrD+ BJlyqWGYYENpvAi+mtx+tY/mFLb4c4feDQ7GIJM4+g== X-Google-Smtp-Source: APXvYqzPOP2gOOc5DBV9XuzuV2a193mEHyb528qgbNc3Bp2i3MBfGzuYoxuk7o/48MumZcUSZcljDgINrFTYeIRh34Y= X-Received: by 2002:a02:94a1:: with SMTP id x30mr5818458jah.82.1552748279613; Sat, 16 Mar 2019 07:57:59 -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> In-Reply-To: <647012f4-c221-addf-51ab-586014e8f435@i-love.sakura.ne.jp> From: Dmitry Vyukov Date: Sat, 16 Mar 2019 15:57:48 +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 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.