From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756159Ab2CGVXB (ORCPT ); Wed, 7 Mar 2012 16:23:01 -0500 Received: from jonshouse.co.uk ([91.84.151.33]:35734 "EHLO mail.jonshouse.co.uk" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755176Ab2CGVWy (ORCPT ); Wed, 7 Mar 2012 16:22:54 -0500 Subject: Re: Random process lockup on ARM board: alsa-lib-1.0.25, FUTEX_WAIT_PRIVATE From: Jonathan Andrews Reply-To: jon@jonshouse.co.uk To: Darren Hart Cc: Huang Shijie , linux-kernel@vger.kernel.org In-Reply-To: <4F57C007.5050006@linux.intel.com> References: <1329393691.6830.20.camel@jonspc> <1329512682.29051.1.camel@jonspc> <1329570128.6670.0.camel@jonspc> <4F400BBF.9020707@ladisch.de> <1329603022.1089.57.camel@jonspc> <4F41FC28.1070605@ladisch.de> <1329926198.22918.10.camel@jonspc> <4F45167A.6080706@ladisch.de> <1330043397.4669.44.camel@jonspc> <4F57C007.5050006@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 07 Mar 2012 21:22:48 +0000 Message-ID: <1331155368.14407.109.camel@jonspc> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 (2.28.3-1.fc12) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-03-07 at 12:07 -0800, Darren Hart wrote: > > On 02/29/2012 01:12 AM, Huang Shijie wrote: > > Hi , > > > > I meet a similar problem with the latest futex code. > > > > I play the video and the processes will hang at the futex. > > Are either of you able to bisect the kernel? I'm not a kernel hacker what do you mean ? > At the very least can you > find two kernels where it works and where it does not? > > Hanging on FUTEX_WAIT_PRIVATE can be the symptom for higher level > problems including userspace locking issues and race conditions. My workload is UDP network audio. I have compiled my code with and without ALSA support. The version without ALSA seems to run forever, the version with ALSA works on ARM for between a few minutes and a few hours. On Intel the same futex stall problem occurs, but it may take runtime of days. I have two processes running. One RX process that takes UDP packets from the network mixes them and presents them to ALSA as an audio stream, the second process takes audio from the sound device and transmits it as a UDP audio stream. The two processes are independent. My workload is atypical as I need to both transmit and receive audio via UDP on a 27/7 basis. So far I have experienced the problem on 3 kernels, but I have tried only 3 kernels it may be all 2.6 kernels that suffer. My development PC is "Linux jonspc 2.6.32.26-175.fc12.i686 #1 SMP Wed Dec 1 21:52:04 UTC 2010 i686 athlon i386 GNU/Linux" My ARM board target: ARM / # uname -a Linux (none) 3.2.5 #2 Wed Feb 22 17:11:52 GMT 2012 armv4tl GNU/Linux And my ARM target running its older kernel was (2.6.36). I have an strace of the process running and stalling on the PC. The file is 2GB, its not a fast link sorry. http://www.jonshouse.co.uk/download/a_stop.txt Many thanks, Jon