From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755265AbaE2DpA (ORCPT ); Wed, 28 May 2014 23:45:00 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:14776 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751217AbaE2Do6 (ORCPT ); Wed, 28 May 2014 23:44:58 -0400 X-IronPort-AV: E=Sophos;i="4.98,932,1392134400"; d="scan'208";a="31165308" Message-ID: <5386AABD.5070708@cn.fujitsu.com> Date: Thu, 29 May 2014 11:34:21 +0800 From: Gu Zheng User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: Dave Chinner CC: , linux-kernel Subject: Re: xfs: possible deadlock warning References: <538571D4.70904@cn.fujitsu.com> <20140528060050.GK8554@dastard> In-Reply-To: <20140528060050.GK8554@dastard> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.100] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dave, On 05/28/2014 02:00 PM, Dave Chinner wrote: > On Wed, May 28, 2014 at 01:19:16PM +0800, Gu Zheng wrote: >> Hi all, >> When running the latest Linus' tree, the following possible deadlock warning occurs. > > false positive. There isn't a deadlock between inode locks on > different filesystems. i.e. there is no dependency between shmem > inodes and xfs inodes, nor on their security contexts. Nor can you > take a page fault on a directory inode, which is the XFS inode lock > class it's complaining about. If it's really a noisy, can we avoid this? Thanks, Gu > > Fundamentally, the problem here is shmem instantiating a new inode > with the mmap_sem held. That's just plain wrong... Agree, it's better to prepare the file before going into the protection region. > > > Cheers, > > Dave.