From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758127AbYFVW2b (ORCPT ); Sun, 22 Jun 2008 18:28:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755131AbYFVW2X (ORCPT ); Sun, 22 Jun 2008 18:28:23 -0400 Received: from bu3sch.de ([62.75.166.246]:56314 "EHLO vs166246.vserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754015AbYFVW2X (ORCPT ); Sun, 22 Jun 2008 18:28:23 -0400 From: Michael Buesch To: Arnd Bergmann Subject: Re: Oops when using growisofs Date: Mon, 23 Jun 2008 00:28:20 +0200 User-Agent: KMail/1.9.6 (enterprise 0.20070907.709405) Cc: "linux-kernel" , Jens Axboe References: <200806221818.24372.mb@bu3sch.de> <200806222322.05706.arnd@arndb.de> <200806230005.51356.mb@bu3sch.de> In-Reply-To: <200806230005.51356.mb@bu3sch.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200806230028.20643.mb@bu3sch.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 23 June 2008 00:05:51 Michael Buesch wrote: > > Note: r9 and r3 are both NULL pointers. r3 is the value returned from alloc_page_buffers. > > R9 is a copy of that, which gets accessed. > > Hm, yeah. I looked at that code already, but I can't see how it could return > a NULL pointer. Well, actually, it can return a NULL pointer. 928 head = NULL; 929 offset = PAGE_SIZE; 930 while ((offset -= size) >= 0) { ... 949 } 950 return head; So if size, which is a passed in as parameter, is > PAGE_SIZE it will return NULL. The size parameter is calculated by doing blocksize = 1 << inode->i_blkbits; in an earlier function in the callchain. So, well. I dunno what i_blkbits is. There's no docs in struct inode. -- Greetings Michael.