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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77718C433EF for ; Wed, 11 May 2022 20:24:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347771AbiEKUY3 (ORCPT ); Wed, 11 May 2022 16:24:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238984AbiEKUYR (ORCPT ); Wed, 11 May 2022 16:24:17 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0345A72E01; Wed, 11 May 2022 13:24:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=LCKlEcL/+gLbho7zoJo89g9MDYx2GFkg8N7n1nlW+0g=; b=MQpyMZ3nMM+SlSF0Ic+7AggIHS wWCWxLFJNdpcNC/qKw1wNJR3uSo8xMkfiJlq7d2aikSbZG9yuq1pfGOyawWDcFgWnRsla4fbF455Y 3RXCIUoMIO9o6uix81B+J++RZraHoxYIg5AFTEzg2KmNpXSrs7BEjvRicrp5TYhs6s3mYN27kkyAz njPDxaRSeQ75fkZPzqisnL9xIuav4szhmycF8VItK7avDyCoEE8U/Zs7xTZO8x+jizmxi0qGskMhG GsWdK7oyZ7kJDFhpPsgWAmAhF7aiE+T5aNpN2RQ5WYTzC7ql7jtRy3esjCfYNiJNCeB+2D6JHceeB Ayva3vzg==; Received: from [177.183.162.244] (helo=[192.168.0.5]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1noss0-000Aod-US; Wed, 11 May 2022 22:23:41 +0200 Message-ID: <4b003501-f5c3-cd66-d222-88d98c93e141@igalia.com> Date: Wed, 11 May 2022 17:22:22 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH 11/30] um: Improve panic notifiers consistency and ordering Content-Language: en-US To: Petr Mladek , Anton Ivanov , Johannes Berg , Richard Weinberger Cc: akpm@linux-foundation.org, bhe@redhat.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-12-gpiccoli@igalia.com> From: "Guilherme G. Piccoli" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/05/2022 11:28, Petr Mladek wrote: > [...] > It is not clear to me why user mode linux should not care about > the other notifiers. It might be because I do not know much > about the user mode linux. > > Is the because they always create core dump or are never running > in a hypervisor or ...? > > AFAIK, the notifiers do many different things. For example, there > is a notifier that disables RCU watchdog, print some extra > information. Why none of them make sense here? > Hi Petr, my understanding is that UML is a form of running Linux as a regular userspace process for testing purposes. With that said, as soon as we exit in the error path, less "pollution" would happen, so users can use GDB to debug the core dump for example. In later patches of this series (when we split the panic notifiers in 3 lists) these UML notifiers run in the pre-reboot list, so they run after the informational notifiers for example (in the default level). But without the list split we cannot order properly, so my gut feeling is that makes sense to run them rather earlier than later in the panic process... Maybe Anton / Johannes / Richard could give their opinions - appreciate that, I'm not attached to the priority here, it's more about users' common usage of UML I can think of... Cheers, Guilherme