Re: 2.6.23 regression: accessing invalid mmap'ed memory from gdb causes unkillable spinning

Ingo Molnar
2007-11-02T15:37:11Z

* Nick Piggin <npiggin@suse.de> wrote:

> > This means that even if some cpu is stuck in a spinlock loop with
> > interrupts disabled, you'd see it with this thing. The way it works
> > is that cross cpu vectored interrupts are disabled independently of
> > the processor interrupt level on sparc64.
>
> That's really sweet. I'd better put my code where my mouth is as
> well... this patch seems to be about the best we can do as a generic
> fallback without getting a dedicated vector (which has to be done in
> arch code anyway).

btw., in -rt we had something like this implemented as an NMI mechanism
(for x86) - that way it's guaranteed that we get some output even from
locked up CPUs.

Ingo