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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 61BC1C433EF for ; Thu, 19 May 2022 04:36:28 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4L3cWH0F3cz3cHn for ; Thu, 19 May 2022 14:36:27 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=TbYUoDwL; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=igalia.com (client-ip=178.60.130.6; helo=fanzine2.igalia.com; envelope-from=gpiccoli@igalia.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=TbYUoDwL; dkim-atps=neutral Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4L3D735pplz3c7G for ; Wed, 18 May 2022 23:17:35 +1000 (AEST) 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 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 X-Mailman-Approved-At: Thu, 19 May 2022 14:35:20 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Mackerras , Justin Chen , Pavel Machek , Alexander Gordeev , "K. Y. Srinivasan" , Wei Liu , stern@rowland.harvard.edu, xen-devel@lists.xenproject.org, Christian Borntraeger , linux-pm@vger.kernel.org, linux-um@lists.infradead.org, Nicholas Piggin , luto@kernel.org, Mihai Carabas , tglx@linutronix.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, senozhatsky@chromium.org, d.hatayama@jp.fujitsu.com, mhiramat@kernel.org, akpm@linux-foundation.org, linux-hyperv@vger.kernel.org, dave.hansen@linux.intel.com, linux-s390@vger.kernel.org, Stephen Hemminger , Vasily Gorbik , vgoyal@redhat.com, Sven Schnelle , Andrea Parri , linux-xtensa@linux-xtensa.org, john.ogness@linutronix.de, Scott Branden , Doug Berger , Markus Mayer , hidehiro.kawai.ez@hitachi.com, linux-arm-kernel@lists.infradead.org, kernel-dev@igalia.com, fabiomirmar@gmail.com, halves@canonical.com, alejandro.j.jimenez@oracle.com, feng.tang@intel.com, zhenwei pi , will@kernel.org, Florian Fainelli , bhe@redhat.com, corbet@lwn.net, Dexuan Cui , Evan Green , bcm-kernel-feedback-list@broadcom.com, Tianyu Lan , keescook@chromium.org, arnd@arndb.de, Haiyang Zhang , rostedt@goodmis.org, rcu@vger.kernel.org, bp@alien8.de, openipmi-developer@lists.sourceforge.net, Thomas Bogendoerfer , linux-parisc@vger.kernel.org, Sebastian Reichel , linux-alpha@vger.kernel.org, Brian Norris , "David S. Miller" , peterz@infradead.org, linux-remoteproc@vger.kernel.org, mikelley@microsoft.com, sparclinux@vger.kernel.org, Lee Jones , Ard Biesheuvel , linux-leds@vger.kernel.org, x86@kernel.org, mingo@redhat.com, dyoung@redhat.com, paulmck@kernel.org, Heiko Carstens , Shile Zhang , Wang ShaoBo , Christophe JAILLET , David Gow , linux-tegra@vger.kernel.org, andriy.shevchenko@linux.intel.com, Hari Bathini , linux-edac@vger.kernel.org, jgross@suse.com, netdev@vger.kernel.org, kernel@gpiccoli.net, kexec@lists.infradead.org, linux-mips@vger.kernel.org, Julius Werner , vkuznets@redhat.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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!