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 EE32CC4332F for ; Wed, 18 May 2022 13:17:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237614AbiERNRb (ORCPT ); Wed, 18 May 2022 09:17:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237454AbiERNR2 (ORCPT ); Wed, 18 May 2022 09:17:28 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7106A0D1F; Wed, 18 May 2022 06:17:25 -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=OR5WoGq1CiBDAgHBnMc6HRC3gZH7AlGvCLosZhpaTuo=; b=TbYUoDwLrw469UplQy2vOqzaUT pf9sYNhexiBEPGvwhLTHv/6lRpXHwZ6JfGGGGlsulYDVL6Ab6bTmmTfDu2arTCnucsnl3GTbcEJxy upUnjbTokylG1GlBlNoIFnEYhQoJuUa0AZWIVQLFFH54ECZKBuEMlIuh1SegIV664GotghzpLED+P tR0zE2dTdCcBKJ1ysKdatz+cCxii4k2F+OmNsFrEsRpmHW6NOWBwJw1oxdcsL+W3TvLq2ZgOX3GYp M0Pw2BUK0uK+s/Hb66H/45XrhqyaGuP4iDdvJd10W7kvlAK6+nwFNgEfr5ANXylTesYuPYEKJpUan NoQkEgFA==; Received: from 200-161-159-120.dsl.telesp.net.br ([200.161.159.120] helo=[192.168.1.60]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1nrJY9-009xvH-Gp; Wed, 18 May 2022 15:17:13 +0200 Message-ID: Date: Wed, 18 May 2022 10:16:20 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list Content-Language: en-US To: Petr Mladek Cc: David Gow , Evan Green , Julius Werner , Scott Branden , bcm-kernel-feedback-list@broadcom.com, Sebastian Reichel , linux-pm@vger.kernel.org, Florian Fainelli , akpm@linux-foundation.org, bhe@redhat.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.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-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, Alexander Gordeev , Andrea Parri , Ard Biesheuvel , Benjamin Herrenschmidt , Brian Norris , Christian Borntraeger , Christophe JAILLET , "David S. Miller" , Dexuan Cui , Doug Berger , Haiyang Zhang , Hari Bathini , Heiko Carstens , Justin Chen , "K. Y. Srinivasan" , Lee Jones , Markus Mayer , Michael Ellerman , Mihai Carabas , Nicholas Piggin , Paul Mackerras , Pavel Machek , Shile Zhang , Stephen Hemminger , Sven Schnelle , Thomas Bogendoerfer , Tianyu Lan , Vasily Gorbik , Wang ShaoBo , Wei Liu , zhenwei pi References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-20-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: netdev@vger.kernel.org On 18/05/2022 04:58, Petr Mladek wrote: > [...] >> I does similar things like kmsg_dump() so it should be called in >> the same location (after info notifier list and before kdump). >> >> A solution might be to put it at these notifiers at the very >> end of the "info" list or make extra "dump" notifier list. > > I just want to point out that the above idea has problems. > Notifiers storing kernel log need to be treated as kmsg_dump(). > In particular, we would need to know if there are any. > We do not need to call "info" notifier list before kdump > when there is no kernel log dumper registered. > Notifiers respect the priority concept, which is just a number that orders the list addition (and the list is called in order). I've used the last position to panic_print() [in patch 25] - one idea here is to "reserve" the last position (represented by INT_MIN) for notifiers that act like kmsg_dump(). I couldn't find any IIRC, but that doesn't prevent us to save this position and comment about that. Makes sense to you ? Cheers!