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=-13.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS 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 3F917C43464 for ; Sat, 19 Sep 2020 00:47:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E729F21D7B for ; Sat, 19 Sep 2020 00:47:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600476466; bh=GFKsAemW7eKRuJ6K11IiY8exAIttJyNQaweQ9T2fkIo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=Zdankv78cB6GanocPgqBUi2EAuV6096Ety53tBZj5UaHZtIgMeXc9cEPBSY1qihcV ROaS+vzr6ENlio6vzbpk6TLUIZQQoOOJU0Qh/i3uRbziLc3X5/jMEKjE05gXUPu4WC EKep8oafEkD13vtLgfcsbJxvl0z6HPytI4B31XoA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726293AbgISArp (ORCPT ); Fri, 18 Sep 2020 20:47:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:48058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726054AbgISArp (ORCPT ); Fri, 18 Sep 2020 20:47:45 -0400 Received: from X1 (unknown [67.22.170.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CC4D521D20; Sat, 19 Sep 2020 00:47:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600476465; bh=GFKsAemW7eKRuJ6K11IiY8exAIttJyNQaweQ9T2fkIo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=kuJSQHj6kqUn/d6d0FUUL3Wxi5+lt/cxNWDddHZZVy01MHrFaukn+IPCdx1woPla6 PJmxi9Nekevk02mColMXI0b04UuyfG7QcdY3NtDdJwIQhdHO2n6jerN+51Qw6jBT64 oC6Ea1iVCeglIjgWjfSzI6cxispirMrVInuXHP1E= Date: Fri, 18 Sep 2020 17:47:43 -0700 From: Andrew Morton To: Dave Young Cc: bhe@redhat.com, Eric Biederman , linux-kernel@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [PATCH] Only allow to set crash_kexec_post_notifiers on boot time Message-Id: <20200918174743.0994c59f058451948837dcb6@linux-foundation.org> In-Reply-To: <20200918032546.GA4180@dhcp-128-65.nay.redhat.com> References: <20200918032546.GA4180@dhcp-128-65.nay.redhat.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 18 Sep 2020 11:25:46 +0800 Dave Young wrote: > crash_kexec_post_notifiers enables running various panic notifier > before kdump kernel booting. This increases risks of kdump failure. > It is well documented in kernel-parameters.txt. We do not suggest > people to enable it together with kdump unless he/she is really sure. > This is also not suggested to be enabled by default when users are > not aware in distributions. > > But unfortunately it is enabled by default in systemd, see below > discussions in a systemd report, we can not convince systemd to change > it: > https://github.com/systemd/systemd/issues/16661 > > Actually we have got reports about kdump kernel hangs in both s390x > and powerpcle cases caused by the systemd change, also some x86 cases > could also be caused by the same (although that is in Hyper-V code > instead of systemd, that need to be addressed separately). > > Thus to avoid the auto enablement here just disable the param writable > permission in sysfs. > Well. I don't think this is at all a desirable way of resolving a disagreement with the systemd developers At the above github address I'm seeing "ryncsn added a commit to ryncsn/systemd that referenced this issue 9 days ago", "pstore: don't enable crash_kexec_post_notifiers by default". So didn't that address the issue?