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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 285ACC47404 for ; Fri, 11 Oct 2019 22:16:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD50F2196E for ; Fri, 11 Oct 2019 22:16:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570832197; bh=M1UCWtUQBgIjYG4651k6EPCtET4bBtdbxlyASuHK0mo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=IEzxDfx74HSqIa/911xfsZkA8id04oqRL/ttr/mmQ+DZmpnrzdF/TsVUpaFP3zJuo L8reIKqIgJWRvKWS9t9G/xb58HtDhNe1GlIUmKZztYvJUI+nE9MDQhN3DRtoHpAoAc +wgg7ZeTcM9Phbutax3qyyq8nZRa6Q/wKYIrZ+b8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729397AbfJKWQf (ORCPT ); Fri, 11 Oct 2019 18:16:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:36914 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729124AbfJKWQf (ORCPT ); Fri, 11 Oct 2019 18:16:35 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A53F9206CD; Fri, 11 Oct 2019 22:16:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570832195; bh=M1UCWtUQBgIjYG4651k6EPCtET4bBtdbxlyASuHK0mo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=CPXMhtAQCg6yCVsqHqY7yrIWbqdBfmUiop4Rh8U1wiqL+qqTxu2kcQyM0ztXuLOi9 gcrmh6X3VluuEsKamMJVzIlILQjiX8ukDnY4x1wSAnsZEyKPZZ1vsEXEk4+6/KtU1b /cP8xYxgIvk2o3RrgxFPDoJdCmJkJWhCofl1nW9U= Date: Fri, 11 Oct 2019 15:16:34 -0700 From: Andrew Morton To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Greg Kroah-Hartman , "Rafael J. Wysocki" , Michal Hocko , "Aneesh Kumar K.V" Subject: Re: [PATCH v1] drivers/base/memory.c: Don't access uninitialized memmaps in soft_offline_page_store() Message-Id: <20191011151634.0b566c9e32e8d0e11181d025@linux-foundation.org> In-Reply-To: <20191010141200.8985-1-david@redhat.com> References: <20191010141200.8985-1-david@redhat.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 10 Oct 2019 16:12:00 +0200 David Hildenbrand wrote: > Uninitialized memmaps contain garbage and in the worst case trigger kernel > BUGs, especially with CONFIG_PAGE_POISONING. They should not get > touched. > > Right now, when trying to soft-offline a PFN that resides on a memory > block that was never onlined, one gets a misleading error with > CONFIG_PAGE_POISONING: > :/# echo 5637144576 > /sys/devices/system/memory/soft_offline_page > [ 23.097167] soft offline: 0x150000 page already poisoned > > But the actual result depends on the garbage in the memmap. > > soft_offline_page() can only work with online pages, it returns -EIO in > case of ZONE_DEVICE. Make sure to only forward pages that are online > (iow, managed by the buddy) and, therefore, have an initialized memmap. > > Add a check against pfn_to_online_page() and similarly return -EIO. > > Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visible after d0dc12e86b319 Should this be cc:stable? What is the relationship between this and some similar fixes in the series "mm/memory_hotplug: Shrink zones before removing memory", v6? Should any of the patches in "mm/memory_hotplug: Shrink zones before removing memory", v6 be cc:stable?