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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2DF20C2BA19 for ; Tue, 14 Apr 2020 17:31:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CD8AA2054F for ; Tue, 14 Apr 2020 17:31:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD8AA2054F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3E8508E0033; Tue, 14 Apr 2020 13:31:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 399528E0001; Tue, 14 Apr 2020 13:31:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2880D8E0033; Tue, 14 Apr 2020 13:31:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0202.hostedemail.com [216.40.44.202]) by kanga.kvack.org (Postfix) with ESMTP id 0EB248E0001 for ; Tue, 14 Apr 2020 13:31:17 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id BFF2D1CDA for ; Tue, 14 Apr 2020 17:31:16 +0000 (UTC) X-FDA: 76707151752.11.hour21_4551baaf94435 X-HE-Tag: hour21_4551baaf94435 X-Filterd-Recvd-Size: 2748 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Apr 2020 17:31:16 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 834FC30E; Tue, 14 Apr 2020 10:31:15 -0700 (PDT) Received: from [192.168.0.14] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1A25F3F6C4; Tue, 14 Apr 2020 10:31:09 -0700 (PDT) Subject: Re: [PATCH 0/3] kexec/memory_hotplug: Prevent removal and accidental use To: Dave Young Cc: Baoquan He , Anshuman Khandual , Catalin Marinas , Bhupesh Sharma , kexec@lists.infradead.org, linux-mm@kvack.org, Eric Biederman , Andrew Morton , Will Deacon , linux-arm-kernel@lists.infradead.org References: <20200326180730.4754-1-james.morse@arm.com> <20200330135522.GE6352@MiWiFi-R3L-srv> <2bdfbb1c-49da-d476-4a38-f91937105ae3@arm.com> <20200331034612.GB83248@dhcp-128-65.nay.redhat.com> From: James Morse Message-ID: <7cfeaf4e-a869-16be-3fe6-521a41d94508@arm.com> Date: Tue, 14 Apr 2020 18:31:05 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200331034612.GB83248@dhcp-128-65.nay.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Dave, On 31/03/2020 04:46, Dave Young wrote: > I agreed that file load is still not widely used, but in the long run > we should not maintain both of them all the future time. Especially > when some kernel-userspace interfaces need to be introduced, file load > will have the natural advantage. We may keep the kexec_load for other > misc usecases, but we can use file load for the major modern > linux-to-linux loading. I'm not saying we can do it immediately, just > thought we should reduce the duplicate effort and try to avoid hacking if > possible. Sure. My aim here is to never debug this problem again. > Anyway about this particular issue, I wonder if we can just reload with > a udev rule as replied in another mail. What if it doesn't? I can't find such a rule on my debian machine. I don't think user-space can be relied on for something like this. The best we could hope for here is a dying gasp from the old kernel: | kexec: memory layout changed since kexec load, this may not work. | Bye! ... assuming anyone sees such a message. Thanks, James