From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lehmann Subject: Re: Silent corruption on AMD64 Date: Sat, 31 Mar 2007 20:20:42 -0700 Message-ID: <20070401032042.GU15189@vitelus.com> References: <20070401012736.GT15189@vitelus.com> <20070331195236.7c818ed5.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from vitelus.com ([63.99.9.247]:36158 "EHLO vitelus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751924AbXDADVS (ORCPT ); Sat, 31 Mar 2007 23:21:18 -0400 Content-Disposition: inline In-Reply-To: <20070331195236.7c818ed5.akpm@linux-foundation.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org On Sat, Mar 31, 2007 at 07:52:36PM -0700, Andrew Morton wrote: > Are you able to provide us with some before-and-after data so we > can see this corruption. > > See, if it's dropped-bits or shifted-data or eight-byte-aligned > kernel addresses or whatever, that helps us generate theories.. Sure. I created a large file containing the repeating ASCII string "abcdefgh", and subjected it to the corruption I described earlier. The correct hex sequence is: 61 62 63 64 65 66 67 68 Here were some of the permutations that I found in corrupted copies: 61 62 63 64 92 57 5C 0A 61 62 63 64 A2 2D E1 C7 61 62 63 64 11 38 0E B6 61 62 63 64 57 B1 EE 1F 61 62 63 64 E0 3D 10 21 61 62 63 64 97 E1 C0 F5 I did not observe any errors other than replacements of four-byte blocks. These errors always started at addresses in the file that had a remainder of 12 modulo 16 (i.e. the hex addresses always ended in 'C'). There was an average about one error per 300MB.