From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756821Ab0EZToM (ORCPT ); Wed, 26 May 2010 15:44:12 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:40715 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757167Ab0EZToI (ORCPT ); Wed, 26 May 2010 15:44:08 -0400 Date: Wed, 26 May 2010 12:44:02 -0700 From: "Paul E. McKenney" To: Heiko Carstens Cc: linux-kernel@vger.kernel.org, Dagmar Volkmann Subject: Re: rcu: inet_timewait_sock.h:227 invoked rcu_dereference_check() without protection Message-ID: <20100526194402.GD2934@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20100526154507.GC2232@osiris.boeblingen.de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100526154507.GC2232@osiris.boeblingen.de.ibm.com> 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 Wed, May 26, 2010 at 05:45:07PM +0200, Heiko Carstens wrote: > Hi Paul, > > we got the following RCU trace here while doing some tests with 2.6.34 > vanilla with some extra patches on top, but which do not touch RCU nor > inet code. > Would be nice if you could have a look at it. Hello, Heiko, This is fixed by commit 7ec75c582e639d956ce3afd499f67febe6f902a4 in Linus's tree. Thanx, Paul > May 21 09:05:16 h0515017 kernel: =================================================== > May 21 09:05:16 h0515017 kernel: [ INFO: suspicious rcu_dereference_check() usage. ] > May 21 09:05:16 h0515017 kernel: --------------------------------------------------- > May 21 09:05:16 h0515017 kernel: /home/autobuild/BUILD/linux-2.6.34-20100520/include/net/inet_timewait_sock.h:227 invoked rcu_dereference_check() without protection! > May 21 09:05:16 h0515017 kernel: > May 21 09:05:16 h0515017 kernel: other info that might help us debug this: > May 21 09:05:16 h0515017 kernel: > May 21 09:05:16 h0515017 kernel: > May 21 09:05:16 h0515017 kernel: rcu_scheduler_active = 1, debug_locks = 0 > May 21 09:05:16 h0515017 kernel: 1 lock held by swapper/0: > May 21 09:05:16 h0515017 kernel: #0: (/home/autobuild/BUILD/linux-2.6.34-20100520/net/ipv4/tcp_minisocks.c:41){+.-...}, at: [<0000000000158398>] run_timer_softirq+0x1b4/0x354 > May 21 09:05:16 h0515017 kernel: > May 21 09:05:16 h0515017 kernel: stack backtrace: > May 21 09:05:16 h0515017 kernel: CPU: 0 Not tainted 2.6.34-42.x.20100520-s390xdefault #1 > May 21 09:05:16 h0515017 kernel: Process swapper (pid: 0, task: 0000000000812a18, ksp: 0000000000807e00) > May 21 09:05:16 h0515017 kernel: 0000000000000000 000000003ffa7bc8 0000000000000002 0000000000000000 > May 21 09:05:16 h0515017 kernel: 000000003ffa7c68 000000003ffa7be0 000000003ffa7be0 000000000056ba7c > May 21 09:05:16 h0515017 kernel: 0000000000000000 0000000000000002 00000000000002d8 0000000000000000 > May 21 09:05:16 h0515017 kernel: 000000000000000d 0000000000000000 000000003ffa7c38 000000000000000e > May 21 09:05:16 h0515017 kernel: 00000000005c48a8 0000000000105a20 000000003ffa7bc8 000000003ffa7c10 > May 21 09:05:16 h0515017 kernel: Call Trace: > May 21 09:05:16 h0515017 kernel: ([<000000000010596e>] show_trace+0x142/0x148) > May 21 09:05:16 h0515017 kernel: [<00000000004a5068>] __inet_twsk_kill+0x140/0x14c > May 21 09:05:16 h0515017 kernel: [<00000000004a566c>] inet_twdr_do_twkill_work+0x90/0x130 > May 21 09:05:16 h0515017 kernel: [<00000000004a585a>] inet_twdr_hangman+0x5e/0xec > May 21 09:05:16 h0515017 kernel: [<000000000015842a>] run_timer_softirq+0x246/0x354 > May 21 09:05:16 h0515017 kernel: [<00000000001514ae>] __do_softirq+0xfa/0x1b8 > May 21 09:05:16 h0515017 kernel: [<0000000000112608>] do_softirq+0xe4/0xe8 > May 21 09:05:16 h0515017 kernel: [<0000000000150f3c>] irq_exit+0xc0/0xe0 > May 21 09:05:16 h0515017 kernel: [<000000000010f9ce>] do_extint+0x126/0x17c > May 21 09:05:16 h0515017 kernel: [<0000000000119e5c>] ext_no_vtime+0x28/0x2c > May 21 09:05:16 h0515017 kernel: [<0000000000116c10>] vtime_stop_cpu+0xac/0x100 > May 21 09:05:16 h0515017 kernel: ([<0000000000116bb6>] vtime_stop_cpu+0x52/0x100) > May 21 09:05:16 h0515017 kernel: [<000000000010c1a8>] cpu_idle+0xf8/0x190 > May 21 09:05:16 h0515017 kernel: [<0000000000859cf0>] start_kernel+0x3b4/0x418 > May 21 09:05:16 h0515017 kernel: [<0000000000100020>] _stext+0x20/0x80 > May 21 09:05:16 h0515017 kernel: INFO: lockdep is turned off. > > Thanks, > Heiko