Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753904AbYJYJNp (ORCPT ); Sat, 25 Oct 2008 05:13:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751955AbYJYJNh (ORCPT ); Sat, 25 Oct 2008 05:13:37 -0400 Received: from einhorn.in-berlin.de ([192.109.42.8]:38553 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751771AbYJYJNg (ORCPT ); Sat, 25 Oct 2008 05:13:36 -0400 X-Envelope-From: stefanr@s5r6.in-berlin.de Message-ID: <4902E2FA.10209@s5r6.in-berlin.de> Date: Sat, 25 Oct 2008 11:12:26 +0200 From: Stefan Richter User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.16) Gecko/20080722 SeaMonkey/1.1.11 MIME-Version: 1.0 To: Johannes Weiner CC: Linux Kernel Mailing List , Andrea Righi , Dave Jones , Dave Airlie Subject: Re: lockdep splat from ioctl and mmap fops sharing lock References: <87ljwgj8p1.fsf@saeurebad.de> <87ej27jtvx.fsf@saeurebad.de> <49009375.1070209@s5r6.in-berlin.de> <8763njjmqt.fsf@saeurebad.de> In-Reply-To: <8763njjmqt.fsf@saeurebad.de> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1153 Lines: 29 Johannes Weiner wrote: > Stefan Richter writes: > >> Johannes Weiner wrote: >>> raw1394_ioctl() doing usercopy under fi->state_mutex >>> raw1394_mmap() taking fi->state_mutex under mmap_sem ... >> was the usage of mmap_sem changed after 2.6.27 or were my tests >> insufficient? > > In linux-next/-mm, copy_to/from_user have lockdep annotations telling > that they might fault and therefor acquire the mmap_sem in #PF. > > But since faults on ioctl parameters are so rare, without these > annotations you would probably never see a warning. Thanks for the report and explanation. I logged this as http://bugzilla.kernel.org/show_bug.cgi?id=11823 (dv1394, won't fix) and http://bugzilla.kernel.org/show_bug.cgi?id=11824 (raw1394, to be fixed in the 2.6.28-rc timeframe since it is a post 2.6.27 regression). -- Stefan Richter -=====-==--- =-=- ==--= http://arcgraph.de/sr/ -- 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/