Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753517Ab2FSWhg (ORCPT ); Tue, 19 Jun 2012 18:37:36 -0400 Received: from g1t0028.austin.hp.com ([15.216.28.35]:37474 "EHLO g1t0028.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752990Ab2FSWhf convert rfc822-to-8bit (ORCPT ); Tue, 19 Jun 2012 18:37:35 -0400 From: "Pearson, Greg" To: Andrew Morton CC: "tj@kernel.org" , "hpa@linux.intel.com" , "shangw@linux.vnet.ibm.com" , "mingo@elte.hu" , "yinghai@kernel.org" , "benh@kernel.crashing.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v4] mm/memblock: fix overlapping allocation when doubling reserved array Thread-Topic: [PATCH v4] mm/memblock: fix overlapping allocation when doubling reserved array Thread-Index: AQHNTazT7gA1rM+IWEu4nQq9TARp25cCNneAgAAFvYA= Date: Tue, 19 Jun 2012 22:35:08 +0000 Message-ID: <4FE0FE9B.8020401@hp.com> References: <1340063278-31601-1-git-send-email-greg.pearson@hp.com> <20120619151435.10c16aed.akpm@linux-foundation.org> In-Reply-To: <20120619151435.10c16aed.akpm@linux-foundation.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120618 Thunderbird/14.0 x-originating-ip: [16.210.48.11] Content-Type: text/plain; charset=US-ASCII Content-ID: <3177E2BB60E9DF4792AAA88EEC01117A@Compaq.com> Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1558 Lines: 35 On 06/19/2012 04:14 PM, Andrew Morton wrote: > On Mon, 18 Jun 2012 17:47:58 -0600 > Greg Pearson wrote: > >> The __alloc_memory_core_early() routine will ask memblock for a range >> of memory then try to reserve it. If the reserved region array lacks >> space for the new range, memblock_double_array() is called to allocate >> more space for the array. If memblock is used to allocate memory for >> the new array it can end up using a range that overlaps with the range >> originally allocated in __alloc_memory_core_early(), leading to possible >> data corruption. > OK, but we have no information about whether it *does* lead to data > corruption. Are there workloads which trigger this? End users who are > experiencing problems? > > See, I (and others) need to work out whether this patch should be > included in 3.5 or even earlier kernels. To do that we often need the > developer to tell us what the impact of the bug is upon users. Please > always include this info when fixing bugs. Andrew, I'm currently working on a prototype system that exhibits the data corruption problem when doubling the reserved array while booting the system. This system will be a released product in the future. I'll remember to include this information in the patch next time. Thanks -- Greg-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/