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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 DB90EC43331 for ; Mon, 30 Mar 2020 08:49:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AED7020732 for ; Mon, 30 Mar 2020 08:49:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NIorDYb7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729741AbgC3ItQ (ORCPT ); Mon, 30 Mar 2020 04:49:16 -0400 Received: from mail-qk1-f195.google.com ([209.85.222.195]:35880 "EHLO mail-qk1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729451AbgC3ItQ (ORCPT ); Mon, 30 Mar 2020 04:49:16 -0400 Received: by mail-qk1-f195.google.com with SMTP id d11so18105248qko.3 for ; Mon, 30 Mar 2020 01:49:15 -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=1MvP6jjTClxZjomf4y/1rTjGh6SHCpZ+cZ78lowmGv8=; b=NIorDYb71y+7N2hKRlp459wSMGgmYVKq560Mqrp50kXGZ5X1N4RQG8zmyAGaMTgmdu /lte169yYFNWz9xu2FXn9x/5/AnDgx+Js5Yp9fQNJ2zqN/EJJgSpoThMp2ASaRu74cII eQFMD6a4VIYD+2/ukQ1lePK7USRLwTht8TGVzxkVxbPRRuL49hEIQ8Fh02CVS8MjBp6w /4UUUC0BpnyaE3siOwbjfcDRllJsn9kr+crGB4Zyzwa0taRL20wNBzaGS/r1OyFb1QP+ dljUWmj7XoazBtedDLO+hMrvobuLwhnbE2lJTEzfZQXjFxixzUn5fIueto0FhUBK5ANC 7SPg== 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=1MvP6jjTClxZjomf4y/1rTjGh6SHCpZ+cZ78lowmGv8=; b=sRDKehb1yc2YOUD+puo3F3K8a4oPiOEjCl6UHID13PPWF4Sdl5V90PRf1/FGtd9X8v KgSImKc4ZEMlVD3fdGW1i6Wqo2T4vaoTd3y2LNl0cOwJ3er3GExvXNakDGmvkHYyDlO6 6sa24y8sZqjP5+5KQXPdskPgmlVeYfZz8v52n5tYq+kFlRMmiXJbca9LTp+ZfTw8kJmB yhyp+ZV/KYCcKcgGROaS0JMd/LzhWLqbjmNJhAN/h9gKCdfZQk9qtPdfASPANTA758I5 criHaBYKR9YykRn/HH7Zj/PbpgIJFpwV55M8W7dqziZBjP6j9Js5/iM1I9o3qT360ap6 fSug== X-Gm-Message-State: ANhLgQ2qGWMF+kIxJQoVR8oMXSHH4CVEmfYjYse1wp4kUIKhILJl+vtE l0L13f8zDtgvTy9Xo5qw1Tz3zwTtd5aWvUm7UqqCug== X-Google-Smtp-Source: ADFU+vvlvHS5oQnOdCxt81qF7x6wm/zJf8J4tpcLPxVGfcXFv9+a0L5awM5x4RTeoTRt8rXpmBKr+hKoCBFa0/LAA9E= X-Received: by 2002:a05:620a:348:: with SMTP id t8mr9415600qkm.407.1585558154683; Mon, 30 Mar 2020 01:49:14 -0700 (PDT) MIME-Version: 1.0 References: <20200327223646.20779-1-gpiccoli@canonical.com> <7fe65aef-94e1-b51a-0434-b1fe9d402d7b@i-love.sakura.ne.jp> In-Reply-To: From: Dmitry Vyukov Date: Mon, 30 Mar 2020 10:49:03 +0200 Message-ID: Subject: Re: [PATCH V3] kernel/hung_task.c: Introduce sysctl to print all traces when a hung task is detected To: Guilherme Piccoli Cc: Tetsuo Handa , LKML , syzkaller , kernelci@groups.io, CKI Project , kbuild test robot , workflows@vger.kernel.org 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 Mon, Mar 30, 2020 at 2:43 AM Guilherme Piccoli wrote: > > Hi Tetsuo and Dmitry, thanks for noticing this Tetsuo. And sorry for > not looping you in the patch Dmitry, I wasn't aware that you were > working with testing. By the way, I suggest people interested in linux > testing to create a ML; I'd be glad to have looped such list, but I > couldn't find information about a group dealing with testing. > > So Tetsuo, you got it right: just change it to > "sysctl.kernel.hung_task_all_cpu_backtrace=1" and that should work > fine, once Vlastimil's patch gets merged (and I hope it happens soon). > Cheers, > > > Guilherme +LKML, workflows, syzkaller, kernelci, cki, kbuild Tetsuo, thanks for notifying again. Yes, kernel devs breaking all testing happens from time to time and currently there is no good way to address this. Other things I remember is the introduction of CONFIG_DEBUG_MEMORY, which defaults to =n and disables KASAN, which in turn produced an explosion of assorted crashes caused by memory corruptions; also periodic changes in kernel crash messages which I assume all testing systems parse and need to understand. Is there already a mailing list for this? Or should we create one? I.e. announce and changes that may need actions from all testing systems. Another thing that may benefit from announcements is addition of new useful debugging configs. Currently they are introduced silently and don't reach the target audience.