From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756388Ab0FQANq (ORCPT ); Wed, 16 Jun 2010 20:13:46 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:55583 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755476Ab0FQANp (ORCPT ); Wed, 16 Jun 2010 20:13:45 -0400 Date: Wed, 16 Jun 2010 17:13:43 -0700 From: "Paul E. McKenney" To: Miles Lane Cc: linux-kernel@vger.kernel.org Subject: Re: 2.6.35-rc3 - include/linux/fdtable.h:85 invoked rcu_dereference_check() without protection! Message-ID: <20100617001343.GL2457@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jun 13, 2010 at 02:36:03AM -0400, Miles Lane wrote: > [ 2074.377176] [ INFO: suspicious rcu_dereference_check() usage. ] > [ 2074.377180] --------------------------------------------------- > [ 2074.377185] include/linux/fdtable.h:85 invoked > rcu_dereference_check() without protection! > [ 2074.377189] > [ 2074.377190] other info that might help us debug this: > [ 2074.377191] > [ 2074.377195] > [ 2074.377196] rcu_scheduler_active = 1, debug_locks = 1 > [ 2074.377200] no locks held by gvfsd/4402. > [ 2074.377203] > [ 2074.377204] stack backtrace: > [ 2074.377209] Pid: 4402, comm: gvfsd Not tainted 2.6.35-rc3 #1 > [ 2074.377213] Call Trace: > [ 2074.377226] [] lockdep_rcu_dereference+0x9d/0xa5 > [ 2074.377235] [] fcheck_files+0x5c/0xc9 > [ 2074.377242] [] fget_light+0x35/0x96 > [ 2074.377250] [] do_sys_poll+0x1ff/0x3e5 > [ 2074.377257] [] ? __pollwait+0x0/0xc7 > [ 2074.377264] [] ? pollwake+0x0/0x4f > [ 2074.377271] [] ? pollwake+0x0/0x4f > [ 2074.377277] [] ? pollwake+0x0/0x4f > [ 2074.377285] [] ? __sock_recvmsg_nosec+0x65/0x6e > [ 2074.377292] [] ? __sock_recvmsg+0x49/0x54 > [ 2074.377299] [] ? sock_aio_read+0xc2/0xd6 > [ 2074.377307] [] ? do_sync_read+0xc6/0x103 > [ 2074.377316] [] ? security_file_permission+0x11/0x13 > [ 2074.377324] [] ? sysret_check+0x2e/0x69 > [ 2074.377331] [] sys_poll+0x50/0xbb > [ 2074.377338] [] system_call_fastpath+0x16/0x1b Hmmm... This was supposed to have been fixed by the following: http://lkml.org/lkml/2010/5/11/489 The rcu_my_thread_group_empty() function that it depends on is in mainline, but this is not. Checking the -vfs tree... Not seeing it there, either. I will repost the patch. Thank you for following up on this!!! Thanx, Paul