Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756407AbYFODaY (ORCPT ); Sat, 14 Jun 2008 23:30:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755587AbYFODaL (ORCPT ); Sat, 14 Jun 2008 23:30:11 -0400 Received: from E23SMTP03.au.ibm.com ([202.81.18.172]:37981 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755562AbYFODaJ (ORCPT ); Sat, 14 Jun 2008 23:30:09 -0400 Date: Sat, 14 Jun 2008 20:30:01 -0700 From: "Paul E. McKenney" To: Alexey Dobriyan Cc: Oleg Nesterov , Adrian Bunk , "Rafael J. Wysocki" , Linux Kernel Mailing List , Linus Torvalds Subject: Re: [Bug #10815] 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0 Message-ID: <20080615033001.GE26421@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20080613135255.GB21341@cs181133002.pp.htv.fi> <20080614144200.GA26421@linux.vnet.ibm.com> <20080614145839.GA10523@tv-sign.ru> <20080614181212.GB26421@linux.vnet.ibm.com> <20080614194338.GA4820@martell.zuzino.mipt.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080614194338.GA4820@martell.zuzino.mipt.ru> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3247 Lines: 80 On Sat, Jun 14, 2008 at 11:43:38PM +0400, Alexey Dobriyan wrote: > On Sat, Jun 14, 2008 at 11:12:12AM -0700, Paul E. McKenney wrote: > > On Sat, Jun 14, 2008 at 06:58:39PM +0400, Oleg Nesterov wrote: > > > On 06/14, Paul E. McKenney wrote: > > > > > > > > On Fri, Jun 13, 2008 at 04:52:55PM +0300, Adrian Bunk wrote: > > > > > On Sat, Jun 07, 2008 at 10:42:57PM +0200, Rafael J. Wysocki wrote: > > > > > > This message has been generated automatically as a part of a report > > > > > > of recent regressions. > > > > > > > > > > > > The following bug entry is on the current list of known regressions > > > > > > from 2.6.25. Please verify if it still should be listed. > > > > > > > > > > > > > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=10815 > > > > > > Subject : 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0 > > > > > > Submitter : Alexey Dobriyan > > > > > > Date : 2008-05-27 09:23 (12 days old) > > > > > > References : http://lkml.org/lkml/2008/5/27/9 > > > > > > Handled-By : Oleg Nesterov > > > > > > Linus Torvalds > > > > > > Paul E. McKenney > > > > > > Patch : http://lkml.org/lkml/2008/5/28/16 > > > > > > > > > > What happened with this issue? > > > > > > > > The patch listed above works for me, passes rcutorture, &c. However, > > > > I never have been able to reproduce the original problem, so cannot say > > > > whether it qualifies as a fix. > > > > > > I doubt very much RCU was the reason of this problem. > > > > Although I very much appreciate your confidence in my code, it is new > > code, so therefore under suspicion. > > > > > Alexey, how did you trigger this problem? > > > > One of them involved running LTP while doing 170 kernel builds in > > parallel. > > My gut feeling is that find_pid_ns oops, __d_lookup oops and > __call_for_each_cic oops are the same bug. > > And rcutorture failures I've mentioned to Paul privately. Yep, running rcutorture in parallel with LTP, which didn't reproduce for me either. Did the patch at http://lkml.org/lkml/2008/5/28/16 help? > Oleg, debugging you've posted never triggered. > > kerneloops suggests that I'm alone. :-( Assuming that the above patch didn't help... As a desperation measure, I could suggest the following patch. Signed-off-by: Paul E. McKenney --- rcupreempt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -urpNa -X dontdiff linux-2.6.26-rc4/kernel/rcupreempt.c linux-2.6.26-rc4-alexey/kernel/rcupreempt.c --- linux-2.6.26-rc4/kernel/rcupreempt.c 2008-05-30 04:39:01.000000000 -0700 +++ linux-2.6.26-rc4-alexey/kernel/rcupreempt.c 2008-06-14 20:24:53.000000000 -0700 @@ -77,7 +77,7 @@ * * GP in GP_STAGES stands for Grace Period ;) */ -#define GP_STAGES 2 +#define GP_STAGES 3 struct rcu_data { spinlock_t lock; /* Protect rcu_data fields. */ long completed; /* Number of last completed batch. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/