From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751373AbaCTFeB (ORCPT ); Thu, 20 Mar 2014 01:34:01 -0400 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:37432 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750863AbaCTFeA (ORCPT ); Thu, 20 Mar 2014 01:34:00 -0400 Date: Thu, 20 Mar 2014 11:03:50 +0530 From: Srikar Dronamraju To: Peter Zijlstra Cc: davidlohr@hp.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, LKML , linuxppc-dev@lists.ozlabs.org, benh@kernel.crashing.org, paulus@samba.org, Paul McKenney Subject: Re: Tasks stuck in futex code (in 3.14-rc6) Message-ID: <20140320053350.GB30295@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20140319152619.GB10406@linux.vnet.ibm.com> <20140319154705.GB8557@laptop.programming.kicks-ass.net> <20140319170829.GD8557@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20140319170829.GD8557@laptop.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14032005-3568-0000-0000-000005209524 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Joy,.. let me look at that with ppc in mind. > > OK; so while pretty much all the comments from that patch are utter > nonsense (what was I thinking), I cannot actually find a real bug. > > But could you try the below which replaces a control dependency with a > full barrier. The control flow is plenty convoluted that I think the > control barrier isn't actually valid anymore and that might indeed > explain the fail. > Unfortunately the patch didnt help. Still seeing tasks stuck # ps -Ao pid,tt,user,fname,tmout,f,wchan | grep futex 14680 pts/0 root java - 0 futex_wait_queue_me 14797 pts/0 root java - 0 futex_wait_queue_me # :> /var/log/messages # echo t > /proc/sysrq-trigger # grep futex_wait_queue_me /var/log/messages | wc -l 334 # [ 6904.211478] Call Trace: [ 6904.211481] [c000000fa1f1b4d0] [0000000000000020] 0x20 (unreliable) [ 6904.211486] [c000000fa1f1b6a0] [c000000000015208] .__switch_to+0x1e8/0x330 [ 6904.211491] [c000000fa1f1b750] [c000000000702f00] .__schedule+0x360/0x8b0 [ 6904.211495] [c000000fa1f1b9d0] [c000000000147348] .futex_wait_queue_me+0xf8/0x1a0 [ 6904.211500] [c000000fa1f1ba60] [c0000000001486dc] .futex_wait+0x17c/0x2a0 [ 6904.211505] [c000000fa1f1bc10] [c00000000014a614] .do_futex+0x254/0xd80 [ 6904.211510] [c000000fa1f1bd60] [c00000000014b25c] .SyS_futex+0x11c/0x1d0 [ 6904.238874] [c000000fa1f1be30] [c00000000000a0fc] syscall_exit+0x0/0x7c [ 6904.238879] java S 00003fff825f6044 0 14682 14076 0x00000080 Is there any other information that I provide that can help? -- Thanks and Regards Srikar Dronamraju