Re: Oops in trace_hardirqs_on (powerpc)

From: Steven Rostedt
Date: Mon Dec 20 2010 - 15:43:42 EST


On Sun, 2010-12-19 at 14:27 +0100, Jörg Sommer wrote:
> Hi Steven,
>
> Steven Rostedt hat am Mon 27. Sep, 21:58 (-0400) geschrieben:
> > On Mon, 2010-09-27 at 14:50 +0200, Jörg Sommer wrote:
> > > Hello Steven,
> > >
> > > Steven Rostedt hat am Wed 22. Sep, 15:44 (-0400) geschrieben:
> > > > Sorry for the late reply, but I was on vacation when you sent this, and
> > > > I missed it while going through email.
> > > >
> > > > Do you still have this issue?
> > >
> > > No. I've rebuild my kernel without TRACE_IRQFLAGS and the problem
> > > vanished, as expected. The problem is, that in some cases the stack is
> > > only two frames deep, which causes the macro CALLER_ADDR1 makes an
> > > invalid access. Someone told me, there a workaround for the problem on
> > > i386, too.
> > >
> > > % sed -n 2p arch/x86/lib/thunk_32.S
> > > * Trampoline to trace irqs off. (otherwise CALLER_ADDR1 might crash)
> >
> > Yes, I remember that problem. When I get back from Tokyo, I'll tried to
> > remember to fix it.
>
> Did you've fixed this problem? The bug report is still marked as open.
> https://bugzilla.kernel.org/show_bug.cgi?id=16573
>

Ah, this email got lost in the hundreds I had when I got back from
Tokyo, sorry about that again :-(

Anyway, it looks like this only affects 32 bit PPC as I can't reproduce
it with my 64 bit one. And also, unfortunately, my 32bit ppc got taken
from me by my kids, so I can't test it on that either.

I'll look to see if I can write up a patch. Perhaps you could test it
for me.

Thanks,

-- Steve


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