From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752596AbbCKXQV (ORCPT ); Wed, 11 Mar 2015 19:16:21 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:33477 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751488AbbCKXQT (ORCPT ); Wed, 11 Mar 2015 19:16:19 -0400 Date: Wed, 11 Mar 2015 16:16:13 -0700 From: "Paul E. McKenney" To: Sasha Levin Cc: Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , LKML , Dave Jones Subject: Re: rcu: frequent rcu lockups Message-ID: <20150311231613.GO5412@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <55009E2C.7070100@oracle.com> <20150311201704.GL5412@linux.vnet.ibm.com> <5500A329.9060509@oracle.com> <20150311204108.GM5412@linux.vnet.ibm.com> <5500BF51.5000806@oracle.com> <20150311230133.GN5412@linux.vnet.ibm.com> <5500CA80.9010007@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5500CA80.9010007@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15031123-0021-0000-0000-000009295376 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 11, 2015 at 07:06:40PM -0400, Sasha Levin wrote: > On 03/11/2015 07:01 PM, Paul E. McKenney wrote: > >> With the commit I didn't hit it yet, but I do see 4 different WARNings: > > I wish that I could say that I am surprised, but the sad fact is that > > I am still shaking the bugs out. > > I have one more to add: > > [ 93.330539] WARNING: CPU: 1 PID: 8 at kernel/rcu/tree_plugin.h:476 rcu_gp_kthread+0x1eaa/0x4dd0() A bit different, but still in the class of a combining-tree bitmask handling bug. Thanx, Paul > [ 93.333515] Modules linked in: > [ 93.334678] CPU: 1 PID: 8 Comm: rcu_preempt Tainted: G W 4.0.0-rc3-next-20150311-sasha-00035-g0a45b48-dirty #2052 > [ 93.338402] ffff8800496f8000 00000000f3e72ee7 ffff880049ac7b28 ffffffff9ea97e89 > [ 93.339495] 0000000000000000 0000000000000000 ffff880049ac7b78 ffffffff941e242a > [ 93.339495] ffffffffa1721038 ffffffff9433bf2a ffffffffa1721040 ffff8800a2822000 > [ 93.339495] Call Trace: > [ 93.339495] [] dump_stack+0x4f/0x7b > [ 93.339495] [] warn_slowpath_common+0xca/0x130 > [ 93.339495] [] ? rcu_gp_kthread+0x1eaa/0x4dd0 > [ 93.339495] [] warn_slowpath_null+0x1a/0x20 > [ 93.339495] [] rcu_gp_kthread+0x1eaa/0x4dd0 > [ 93.339495] [] ? plist_check_head+0x3c/0x50 > [ 93.339495] [] ? cond_synchronize_rcu+0x20/0x20 > [ 93.339495] [] ? trace_hardirqs_on_caller+0x475/0x610 > [ 93.339495] [] ? _raw_spin_unlock_irq+0x69/0xa0 > [ 93.339495] [] ? __schedule+0x993/0x1b90 > [ 93.339495] [] ? ___preempt_schedule+0x12/0x14 > [ 93.339495] [] ? abort_exclusive_wait+0x1d0/0x1d0 > [ 93.339495] [] ? cond_synchronize_rcu+0x20/0x20 > [ 93.339495] [] kthread+0x216/0x2e0 > [ 93.339495] [] ? flush_kthread_work+0x300/0x300 > [ 93.339495] [] ? _raw_spin_unlock_irq+0x30/0xa0 > [ 93.339495] [] ? flush_kthread_work+0x300/0x300 > [ 93.339495] [] ret_from_fork+0x53/0x80 > [ 93.339495] [] ? flush_kthread_work+0x300/0x300 > > > Thanks, > Sasha >