From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933785AbbA2CY5 (ORCPT ); Wed, 28 Jan 2015 21:24:57 -0500 Received: from mail-lb0-f169.google.com ([209.85.217.169]:52362 "EHLO mail-lb0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754105AbbA2CYy (ORCPT ); Wed, 28 Jan 2015 21:24:54 -0500 MIME-Version: 1.0 In-Reply-To: <20150128174817.GQ19109@linux.vnet.ibm.com> References: <7665538633a500255d7da9ca5985547f6a2aa191.1416604491.git.luto@amacapital.net> <54C17139.1040706@oracle.com> <20150123180455.GA3192@pd.tnic> <54C2B396.9090106@oracle.com> <20150128174817.GQ19109@linux.vnet.ibm.com> From: Andy Lutomirski Date: Wed, 28 Jan 2015 13:02:33 -0800 Message-ID: Subject: Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context To: Paul McKenney Cc: Sasha Levin , Borislav Petkov , X86 ML , Linus Torvalds , "linux-kernel@vger.kernel.org" , Peter Zijlstra , Oleg Nesterov , Tony Luck , Andi Kleen , Josh Triplett , =?UTF-8?B?RnLDqWTDqXJpYyBXZWlzYmVja2Vy?= Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 28, 2015 at 9:48 AM, Paul E. McKenney wrote: > On Wed, Jan 28, 2015 at 08:33:06AM -0800, Andy Lutomirski wrote: >> On Fri, Jan 23, 2015 at 5:25 PM, Andy Lutomirski wrote: >> > On Fri, Jan 23, 2015 at 12:48 PM, Sasha Levin wrote: >> >> On 01/23/2015 01:34 PM, Andy Lutomirski wrote: >> >>> On Fri, Jan 23, 2015 at 10:04 AM, Borislav Petkov wrote: >> >>>> On Fri, Jan 23, 2015 at 09:58:01AM -0800, Andy Lutomirski wrote: >> >>>>>> [ 543.999079] Call Trace: >> >>>>>> [ 543.999079] dump_stack (lib/dump_stack.c:52) >> >>>>>> [ 543.999079] lockdep_rcu_suspicious (kernel/locking/lockdep.c:4259) >> >>>>>> [ 543.999079] atomic_notifier_call_chain (include/linux/rcupdate.h:892 kernel/notifier.c:182 kernel/notifier.c:193) >> >>>>>> [ 543.999079] ? atomic_notifier_call_chain (kernel/notifier.c:192) >> >>>>>> [ 543.999079] notify_die (kernel/notifier.c:538) >> >>>>>> [ 543.999079] ? atomic_notifier_call_chain (kernel/notifier.c:538) >> >>>>>> [ 543.999079] ? debug_smp_processor_id (lib/smp_processor_id.c:57) >> >>>>>> [ 543.999079] do_debug (arch/x86/kernel/traps.c:652) >> >>>>>> [ 543.999079] ? trace_hardirqs_on (kernel/locking/lockdep.c:2609) >> >>>>>> [ 543.999079] ? do_int3 (arch/x86/kernel/traps.c:610) >> >>>>>> [ 543.999079] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2554 kernel/locking/lockdep.c:2601) >> >>>>>> [ 543.999079] debug (arch/x86/kernel/entry_64.S:1310) >> >>>>> >> >>>>> I don't know how to read this stack trace. Are we in do_int3, >> >>>>> do_debug, or both? I didn't change do_debug at all. >> >>>> >> >>>> It looks like we're in do_debug. do_int3 is only on the stack but not >> >>>> part of the current frame if I can trust the '?' ... >> >>>> >> >>> >> >>> It's possible that an int3 happened and I did something wrong on >> >>> return that caused a subsequent do_debug to screw up, but I don't see >> >>> how my patch would have caused that. >> >>> >> >>> Were there any earlier log messages? >> >> >> >> Nope, nothing odd before or after. >> > >> > Trinity just survived for a decent amount of time for me with my >> > patches, other than a bunch of apparently expected OOM kills. I have >> > no idea how to tell trinity how much memory to use. >> >> A longer trinity run on a larger VM survived (still with some OOM >> kills, but no taint) with these patches. I suspect that it's a >> regression somewhere else in the RCU changes. I have >> CONFIG_PROVE_RCU=y, so I should have seen the failure if it was there, >> I think. > > If by "RCU changes" you mean my changes to the RCU infrastructure, I am > going to need more of a hint than I see in this thread thus far. ;-) > I can't help much, since I can't reproduce the problem. Presumably if it's a bug in -tip, someone else will trigger it, too. --Andy