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[2620:137:e000::1:20]) by mx.google.com with ESMTP id v6-20020a63f206000000b003c4a040f5bfsi6280473pgh.321.2022.05.19.05.50.48; Thu, 19 May 2022 05:51:00 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@suse.com header.s=susede1 header.b="qJ/FgyV3"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=suse.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234521AbiESHEE (ORCPT + 99 others); Thu, 19 May 2022 03:04:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229850AbiESHEB (ORCPT ); Thu, 19 May 2022 03:04:01 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B09CC275; Thu, 19 May 2022 00:04:00 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id CF6261F9DC; Thu, 19 May 2022 07:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1652943838; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=395st/CngVntAAOn5uSBsdHcf6UJsehUQOcbe6ab9wI=; b=qJ/FgyV3p4LuXUdkZjoAbs2+ewn4o7aNZN0S67D2rC96Mde70WoKxt5D1iYy3vIxFGNywX NYQFStO7xXozlUSKqQPZCblT/M2McgEFa5ttVGDSrZzFsBjH4DUBLxqHsrlOhubnXz8Ip9 VRfQAfc3f6HDJx77hS/XQSQpNXuMeJQ= Received: from suse.cz (unknown [10.100.201.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 813A52C141; Thu, 19 May 2022 07:03:55 +0000 (UTC) Date: Thu, 19 May 2022 09:03:52 +0200 From: Petr Mladek To: "Guilherme G. Piccoli" 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 Subject: Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list Message-ID: References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-20-gpiccoli@igalia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2022-05-18 10:16:20, Guilherme G. Piccoli wrote: > 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. I would ignore it for now. If anyone would want to safe the log then they would need to read it. They will most likely use the existing kmsg_dump() infastructure. In fact, they should use it to avoid a code duplication. Best Regards, Petr