Messages in this thread | | | Date | Tue, 02 Nov 2010 11:28:17 +0100 | From | Tejun Heo <> | Subject | Re: open() on /dev/tty takes 30 seconds on 2.6.36 |
| |
Hello,
On 10/31/2010 12:36 PM, Arnd Bergmann wrote: > 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: >> [<ffffffff81050c60>] warn_slowpath_common+0x85/0x9d >> [<ffffffff81050c92>] warn_slowpath_null+0x1a/0x1c >> [<ffffffff81066861>] worker_enter_idle+0xd6/0xe2 >> [<ffffffff81068453>] worker_thread+0x182/0x19b >> [<ffffffff810682d1>] ? worker_thread+0x0/0x19b >> [<ffffffff8106ba81>] kthread+0x82/0x8a >> [<ffffffff8100aae4>] kernel_thread_helper+0x4/0x10 >> [<ffffffff8106b9ff>] ? kthread+0x0/0x8a >> [<ffffffff8100aae0>] ? 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.
Hmmm... that's a condition which shouldn't happen regardless of being blocked on mutex or whatever. It means that internal book keeping used to manage concurrency went out of sync somehow. I've re-read the code managing nr_running but couldn't spot where the problem could be. Is there any way to reproduce the problem?
Thanks.
-- tejun
| |