From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752491Ab1HVNQZ (ORCPT ); Mon, 22 Aug 2011 09:16:25 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47368 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752175Ab1HVNQY (ORCPT ); Mon, 22 Aug 2011 09:16:24 -0400 Date: Mon, 22 Aug 2011 14:16:21 +0100 From: Al Viro To: Josh Boyer Cc: "Justin P. Mattock" , Peter Zijlstra , "linux-kernel@vger.kernel.org" Subject: Re: INFO: possible circular locking dependency detected 3.1.0-rc2-00190-g3210d19 Message-ID: <20110822131621.GS2203@ZenIV.linux.org.uk> References: <4E51CFD8.2090508@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 22, 2011 at 09:09:14AM -0400, Josh Boyer wrote: > We've had a report of this on 3.0.1 as well. Slightly different > scenario and fs, but the locks in question are the same. > https://bugzilla.redhat.com/show_bug.cgi?id=730998 > > It seems that with CONFIG_PROVE_LOCKING on, might_fault will always > attempt to grab mm->mmap_sem. The common flow here is that getdents > calls filldir, which calls copy_to_user, which is what is calling > might_fault. > > Beyond that, I'm a bit over my head at the moment because I don't know > if the VFS is right and we just need some more lockdep annotations or > if there really is a problem. Don't grab ->i_mutex in ->evict_inode(). Why are you doing that, anyway?