From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755484Ab0JaMHN (ORCPT ); Sun, 31 Oct 2010 08:07:13 -0400 Received: from moutng.kundenserver.de ([212.227.17.10]:60652 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755376Ab0JaMHJ (ORCPT ); Sun, 31 Oct 2010 08:07:09 -0400 From: Arnd Bergmann To: James Cloos Subject: Re: open() on /dev/tty takes 30 seconds on 2.6.36 Date: Sun, 31 Oct 2010 12:36:38 +0100 User-Agent: KMail/1.12.2 (Linux/2.6.35-16-generic; KDE/4.3.2; x86_64; ; ) Cc: Eli Billauer , Andrew Morton , linux-kernel@vger.kernel.org, Tejun Heo References: <4CCBCD8E.1020601@billauer.co.il> <201010310436.18613.arnd@arndb.de> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201010311236.38844.arnd@arndb.de> X-Provags-ID: V02:K0:0WXP+g/YZd+ZgDIH/luquCBbHDey6gYaopSRuMlKPtN wLEvlT5p2T7p9yFGls0idzCq7cs5Pc+LaqsVz/Bp9MkEWYigMH 2vL4mfs4lbjTUgcXCDhqPIPjakwZbRfDjOtVwSnbzQ2UqVtbNm iYPNNwZ4Lo0wbE6/oNs61lM3VtUWrqA7+u4q27zjuij0Dz40gd Wq2w7lnOHFO1Rm1t6m8VQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sunday 31 October 2010, James Cloos wrote: > WARNING: at kernel/workqueue.c:1180 worker_enter_idle+0xd6/0xe2() > Hardware name: MS-7642 > Modules linked in: tcp_diag inet_diag ipt_addrtype xt_dscp xt_string xt_owner xt_multiport xt_iprange xt_hashlimit xt_DSCP xt_NFQUEUE xt_mark xt_connmark tun snd_pcm_oss snd_mixer_oss snd_usb_audio snd_usbmidi_lib snd_rawmidi tpm_tis tpm ppdev parport_pc tpm_bios parport serio_raw edac_core k10temp pcspkr i2c_piix4 shpchp > Pid: 8061, comm: kworker/0:1 Not tainted 2.6.36-carbon1 #18 > Call Trace: > [] warn_slowpath_common+0x85/0x9d > [] warn_slowpath_null+0x1a/0x1c > [] worker_enter_idle+0xd6/0xe2 > [] worker_thread+0x182/0x19b > [] ? worker_thread+0x0/0x19b > [] kthread+0x82/0x8a > [] kernel_thread_helper+0x4/0x10 > [] ? kthread+0x0/0x8a > [] ? kernel_thread_helper+0x0/0x10 > ---[ end trace 756b0818a6415dca ]--- > > That was followed by a number of task blocked for more than 120 seconds > messages, all due to waiting for pty input or output. An example trace: This is triggered by an internal check in the workqueue handling that Tejun introduced. I guess it might be possible that this is triggered by a worker thread being blocked on a mutex, but I don't understand exactly what it is checking for. Arnd