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 A6126C10DCE for ; Fri, 1 Dec 2023 10:37:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378304AbjLAKhe (ORCPT ); Fri, 1 Dec 2023 05:37:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378266AbjLAKha (ORCPT ); Fri, 1 Dec 2023 05:37:30 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3DA22F4 for ; Fri, 1 Dec 2023 02:37:36 -0800 (PST) Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 5061221C55; Fri, 1 Dec 2023 10:37:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1701427054; 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=3AKHXuA9rkIsDSYU4VYYdpC7Z1E4D6XbgmPzoeVMV08=; b=CY5cWtFOcN9jOy0PFWPsrJrLEpFGDaWd6f52ktF+iZ2lmZWLHChlb++7dLUkPDxpsYNoZw cVbos4WRyBhkKA8Ojovn8rsa3/Xmd6J20OADutV0XA77pLK1p9OIdUqTTHXWbt62jgMy89 E4D5c0wnfPIpqefwkppJvFnM515DRS8= Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 2EDF81379A; Fri, 1 Dec 2023 10:37:34 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id D1qICG63aWXNZAAAD6G6ig (envelope-from ); Fri, 01 Dec 2023 10:37:34 +0000 Date: Fri, 1 Dec 2023 11:37:33 +0100 From: Michal Hocko To: Pingfan Liu Cc: Baoquan He , Donald Dutile , Jiri Bohac , Tao Liu , Vivek Goyal , Dave Young , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/4] kdump: crashkernel reservation from CMA Message-ID: References: <91a31ce5-63d1-7470-18f7-92b039fda8e6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Authentication-Results: smtp-out1.suse.de; none X-Spamd-Result: default: False [-1.19 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; RCPT_COUNT_SEVEN(0.00)[9]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_NOT_FQDN(0.50)[]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-0.59)[81.62%] Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 01-12-23 08:54:20, Pingfan Liu wrote: [...] > > I am not aware of any method to detect a driver is going to configure a > > RDMA. > > > > If there is a pattern, scripts/coccinelle may give some help. But I am > not sure about that. I am not aware of any pattern. > > > If this can be resolved, I think this method is promising. > > > > Are you indicating this is a mandatory prerequisite? > > IMHO, that should be mandatory. Otherwise for any unexpected kdump > kernel collapses, it can not shake off its suspicion. I appreciate your carefulness! But I do not really see how such a detection would work and be maintained over time. What exactly is the scope of such a tooling? Should it be limited to RDMA drivers? Should we protect from stray writes in general? Also to make it clear. Are you going to nak the proposed solution if there is no such tooling available? -- Michal Hocko SUSE Labs