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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 9CB57C65C20 for ; Mon, 8 Oct 2018 16:03:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D6E321471 for ; Mon, 8 Oct 2018 16:03:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D6E321471 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726960AbeJHXPz (ORCPT ); Mon, 8 Oct 2018 19:15:55 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:52776 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726452AbeJHXPz (ORCPT ); Mon, 8 Oct 2018 19:15:55 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 893ADED1; Mon, 8 Oct 2018 09:03:29 -0700 (PDT) Received: from [10.1.196.46] (melchizedek.cambridge.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E3B813F5BC; Mon, 8 Oct 2018 09:03:28 -0700 (PDT) Subject: Re: 4.19-rcX: WARN_ON() arch/arm64/kernel/setup.c:271 reserve_memblock_reserved_regions To: Paolo Pisati Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20181008151138.GA19635@harukaze> From: James Morse Message-ID: <47fa0375-ed69-0cbc-9dcb-0cafb9184f24@arm.com> Date: Mon, 8 Oct 2018 17:03:27 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <20181008151138.GA19635@harukaze> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paolo! On 08/10/2018 16:11, Paolo Pisati wrote: > This on my dragonboard 410c: > > ... > [ 0.170657] WARNING: CPU: 2 PID: 1 at arch/arm64/kernel/setup.c:271 reserve_memblock_reserved_regions+0xd4/0x150 > [ 0.170666] Modules linked in: > [ 0.170680] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-dirty #3 > [ 0.170687] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) > [ 0.170696] pstate: 20000005 (nzCv daif -PAN -UAO) > [ 0.170707] pc : reserve_memblock_reserved_regions+0xd4/0x150 > [ 0.170718] lr : reserve_memblock_reserved_regions+0xcc/0x150 > [ 0.170725] sp : ffff000008033d30 > [ 0.170899] Call trace: > [ 0.170910] reserve_memblock_reserved_regions+0xd4/0x150 > [ 0.170921] do_one_initcall+0x58/0x170 > [ 0.170931] kernel_init_freeable+0x1a4/0x264 > [ 0.170942] kernel_init+0x10/0x108 > [ 0.170952] ret_from_fork+0x10/0x18 > [ 0.170962] ---[ end trace c7ce9242331f7319 ]--- > [ 0.170974] name: reserved res: [mem 0xbff00000-0xbfffffff flags 0x200] John Stultz saw this on Hikey, > that memory region corresponds to the ramoops node: ... it was the ramoops description too. There is a patch: https://www.spinics.net/lists/arm-kernel/msg675580.html Which I need to re-spin. This is happening because your reserved-memory isn't described as memory. I mistakenly believed no-one would do this, and I really didn't want to walk both them memory and reserved lists at the same time! mm/page_alloc.c:zero_resv_unavail() has a comment about this: | * Once memblock is changed so such behaviour is not allowed: i.e. | * list of "reserved" memory must be a subset of list of "memory", then | * this code can be removed. > According to the comment in reserve_memblock_reserved_regions(): > and the reserved-memory region evades this condition, but i'm not entirely sure how to > properly fix this - any idea? Ideally reserved-memory would be described as memory. If you need it to be removed from the linear map (e.g. because it needs special memory attributes), use the binding's 'nomap' property. This causes early_init_dt_reserve_memory_arch() to remove the memory instead of marking it reserved. But! DT's that have this reserved-but-not-memory are already out there, so we should work around this in the kernel. Thanks, James