From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 21 Aug 2002 15:05:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 21 Aug 2002 15:05:01 -0400 Received: from pc2-cwma1-5-cust12.swa.cable.ntl.com ([80.5.121.12]:16368 "EHLO irongate.swansea.linux.org.uk") by vger.kernel.org with ESMTP id ; Wed, 21 Aug 2002 15:05:00 -0400 Subject: Re: PROBLEM: kernel BUG in buffer.c From: Alan Cox To: Peter Hicks Cc: linux-kernel@vger.kernel.org In-Reply-To: <3D63E0E8.1080202@POGGS.CO.UK> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.3 (1.0.3-6) Date: 21 Aug 2002 20:10:01 +0100 Message-Id: <1029957001.26845.120.camel@irongate.swansea.linux.org.uk> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2002-08-21 at 19:50, Peter Hicks wrote: > Hi everyone > > I've come across a BUG() in buffer.c, line 2497. I'm running 2.4.19 on a > Pentium III, with no other problems. I'd finished making a backup of an > IRIX installation CD, was mounting the freshly burnt CD, and was greeted > with a hung 'mount' and the following in dmesg: Well its definitely a kernel bug. We should never crash given a bad CD. In this case I think the problem is a little deeper. Our efs code doesn't appear to consider and error the case when its block size is below 2048 bytes. An EFS block is 512 bytes so we tell a 2K sectored device to use 512byte sectors. At this point the kernel rightfully realises that something deeply wrong is happening and aborted. I believe the fix is as follows Make EFS check its not asking for stupid block sizes You can then use a loopback mount to buffer the device and mount the CD that way. I'll fix the EFS code tomorrow