Re: [BUG 2.6.23-rc6-mm1] NMI Watchdog detected LOCKUP on CPU 0

Andrew Morton
2007-09-23T05:36:26Z

On Sun, 23 Sep 2007 13:30:40 +0800 Fengguang Wu <wfg@mail.ustc.edu.cn> wrote:

> > That's interensting. serial_in(). We have had NMI watchdog expiries when
> > the kernel is printing a large amount of stuff out a slow serial port with
> > interrutps disabled. But I thought we'd pretty much plugged those problems
> > by sprinkling touch_nmi_watchdog() in various places.
> >
> > Do you think this is what was happening on your system?
>
> Very likely. I'm running linux with cmdline
> "root=/dev/sda1 ro nmi_watchdog=1 console=ttyS0,115200 console=tty0",
> and doing a lot of printks at the time ;-)

OK. We need to find a suitable place to poke yet another
touch_nmi_watchdog(). Maybe we should give up and put one in
printk().

And you oopsed for different reasons in the nmi-watchdog handling
code too. I think I'll pretend I didn't see that.