Hi,
(x86_64; 2.6.16-rc6;
serial console configured but nothing connected to the serial port)
I'm seeing an occasional soft lockup, maybe in serial8250_console_write().
(drivers/serial/8250.c)
This function calls wait_for_xmitr() [inline], which in worst case
can spin for 1.010 seconds. Could this be the cause of a soft lockup?
[ 101.448855] BUG: soft lockup detected on CPU#0!
[ 101.448858] CPU 0:
[ 101.448860] Modules linked in:
[ 101.448863] Pid: 1, comm: swapper Not tainted 2.6.16-rc6 #3
[ 101.448866] RIP: 0010:[<ffffffff8013009b>] <ffffffff8013009b>{__do_softirq+75}
[ 101.448874] RSP: 0000:ffffffff804dc9a8 EFLAGS: 00000206
[ 101.448877] RAX: ffff81007f63dfd8 RBX: ffffffff804dc8f8 RCX: 000000000000000a
[ 101.448880] RDX: 0000000000000022 RSI: 0000000000000002 RDI: ffff81007f622740
[ 101.448883] RBP: ffffffff8010aef0 R08: 0000000000000083 R09: ffff81007f287638
[ 101.448886] R10: 0000000000000002 R11: 0000000000000000 R12: ffffffff804dc9c8
[ 101.448889] R13: ffffffff80529d00 R14: 0000000000000022 R15: ffffffff8010d34d
[ 101.448892] FS: 0000000000000000(0000) GS:ffffffff80529000(0000) knlGS:0000000000000000
[ 101.448895] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
[ 101.448898] CR2: 0000000000000000 CR3: 0000000000101000 CR4: 00000000000006e0
[ 101.448900]
[ 101.448900] Call Trace: <IRQ> <ffffffff8010bb92>{call_softirq+30}
[ 101.448908] <ffffffff8010d309>{do_softirq+49} <ffffffff8012fe63>{irq_exit+72}
[ 101.448915] <ffffffff80115ab1>{smp_apic_timer_interrupt+75} <ffffffff8010b536>{apic_timer_interrupt+98} <EOI>
[ 101.448923] <ffffffff8028607e>{serial8250_console_write+516} <ffffffff8012add7>{release_console_sem+335}
[ 101.448936] <ffffffff8012b188>{register_console+433} <ffffffff803134cb>{usb_serial_console_init+51}
[ 101.448943] <ffffffff80312556>{usb_serial_probe+3989} <ffffffff8012b8c3>{vprintk+721}
[ 101.448956] <ffffffff803a3bb7>{_spin_unlock_irq+9} <ffffffff8012b93f>{printk+103}
[ 101.448964] <ffffffff8013a084>{call_usermodehelper_keys+274} <ffffffff802f1dc8>{usb_probe_interface+223}
[ 101.448975] <ffffffff8028f1ff>{driver_probe_device+90} <ffffffff8028f35c>{__driver_attach+135}
[ 101.448983] <ffffffff8028f2d5>{__driver_attach+0} <ffffffff8028e726>{bus_for_each_dev+73}
[ 101.448990] <ffffffff8028f094>{driver_attach+28} <ffffffff8028ea48>{bus_add_driver+114}
[ 101.448996] <ffffffff8028f7f9>{driver_register+180} <ffffffff802f1c7a>{usb_register_driver+134}
[ 101.449003] <ffffffff803112e6>{usb_serial_register+570} <ffffffff805550fc>{belkin_sa_init+39}
[ 101.449012] <ffffffff8010820b>{init+451} <ffffffff8010b842>{child_rip+8}
[ 101.449020] <ffffffff80108048>{init+0} <ffffffff8010b83a>{child_rip+0}
---
* Randy.Dunlap <[email protected]> wrote:
> Hi,
>
> (x86_64; 2.6.16-rc6; serial console configured but nothing connected
> to the serial port)
>
> I'm seeing an occasional soft lockup, maybe in
> serial8250_console_write(). (drivers/serial/8250.c)
>
> This function calls wait_for_xmitr() [inline], which in worst case can
> spin for 1.010 seconds. Could this be the cause of a soft lockup?
hm, it shouldnt cause that. Could you try the attached patch [which is
the next-gen softlockup detector], do you get the message even with that
one applied?
Ingo
On Tue, 14 Mar 2006 22:40:49 +0100 Ingo Molnar wrote:
>
> * Randy.Dunlap <[email protected]> wrote:
>
> > Hi,
> >
> > (x86_64; 2.6.16-rc6; serial console configured but nothing connected
> > to the serial port)
> >
> > I'm seeing an occasional soft lockup, maybe in
> > serial8250_console_write(). (drivers/serial/8250.c)
> >
> > This function calls wait_for_xmitr() [inline], which in worst case can
> > spin for 1.010 seconds. Could this be the cause of a soft lockup?
>
> hm, it shouldnt cause that. Could you try the attached patch [which is
> the next-gen softlockup detector], do you get the message even with that
> one applied?
5/5 good boots with your new patch.
5/5 soft lockups without it.
Is this scheduled for post-2.6.16 ?
Thanks,
---
~Randy
* Randy.Dunlap <[email protected]> wrote:
> > > This function calls wait_for_xmitr() [inline], which in worst case can
> > > spin for 1.010 seconds. Could this be the cause of a soft lockup?
> >
> > hm, it shouldnt cause that. Could you try the attached patch [which is
> > the next-gen softlockup detector], do you get the message even with that
> > one applied?
>
> 5/5 good boots with your new patch.
> 5/5 soft lockups without it.
>
> Is this scheduled for post-2.6.16 ?
yes, in theory. Andrew?
Ingo
Ingo Molnar <[email protected]> wrote:
>
>
> * Randy.Dunlap <[email protected]> wrote:
>
> > > > This function calls wait_for_xmitr() [inline], which in worst case can
> > > > spin for 1.010 seconds. Could this be the cause of a soft lockup?
> > >
> > > hm, it shouldnt cause that. Could you try the attached patch [which is
> > > the next-gen softlockup detector], do you get the message even with that
> > > one applied?
> >
> > 5/5 good boots with your new patch.
> > 5/5 soft lockups without it.
> >
> > Is this scheduled for post-2.6.16 ?
>
> yes, in theory. Andrew?
>
Which? timer-irq-driven-soft-watchdog-cleanups.patch? Yup.