PREEMPT problems

Michel Dänzer michel at
Wed Apr 7 09:28:39 EST 2004

On Tue, 2004-04-06 at 02:51, Benjamin Herrenschmidt wrote:
> > Sure enough, -rc2-ben0 is now behaving just as badly as -rc3-ben0.
> > Probably just fluctuation.
> >
> > > I also added a WARN_ON(), do you see it triggered in dmesg ?
> Still can't reproduce any problem here. You are using xfs right ?

Yes. Colin, what about you?

> Maybe it's a filesystem issue... or some driver (USB device ?)

The only USB device I'm using regularly is a mouse.

> that you are using that is allergic to preempt ?

I don't think I'm using anything exotic... do you think ALSA could cause
such problems? The filesystem seems more likely to me, but what do I

> It would be useful if you could spot one of those stuck processes
> and get a backtrace from it. For that, use P<pid> in xmon to get the
> ksp then b<ksp value> to get a backtrace.

I'm back to a non-preempt kernel for the time being, but I'll try to do
that if I ever feel adventurous again, and provided I find out how to
get into xmon.

Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Libre software enthusiast    |

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