[lug] Spurious 8259A interrupt: IRQ7, then hang

[D. Stimits]

Andrew Gilmore wrote:

>
>
> D. Stimits wrote:
>
> > Andrew Gilmore wrote:
> >
> >> I've googled a bit for this one, but come up empty so far.
> >> If anyone has any ideas, that'd be great.
> >>
> >> This is my first seriously misbehaving system under Linux, and I'm 
> a bit
> >> annoyed.
> >>
> >> Symptoms:
> >>
> >> ssh session over ethernet hangs after a few CRs.
> >> Console immediately says:
> >> Spurious 8259A interrupt: IRQ7
> >
> >
> >
> > Perhaps this is not related at all...I once asked Alan Cox and some of
> > the kernel people about the spurious interrupt message, it is normal
> > and irrelevant, some kind of leftover message for developers. Whenever
> > I got lost interrupt, it was related to the IO-APIC on Intel chipsets
> > for SMP. Running with kernel option "noapic" fixed it (and also
> > removed responsiveness that SMP is famous for). With the old system
> > mentioned below, that couldn't possibly be an SMP issue, but I suspect
> > the spurious interrupt is itself in no way related. People suggesting
> > cables and similar possibilities are likely on target. Out of
> > curiousity, what does /proc/interrupts contain? Are any of the related
> > pci devices (like the ethernet card) in any way famous for not liking
> > to share interrupts? There are a significant number of older pci
> > devices that didn't share as well as newer ones...try changing slot of
> > the ethernet card, possibly video card also.
>
>
> Just for fun, I tried noapic. Heh, no dice. The most annoying part of
> this is that I have to have two systems up, and reset after every failure.
>
> I am definitely going to try taking the video card out, and checking for
> shared interrupts.
>
> Since the system is at home, the turnaround time on these suggestions is
> fairly long. Thanks for any ideas you have.
>
> I assume this is a hardware problem, but is there any possibility that
> it is actually a kernel problem?


Of course it could be a kernel problem, especially with respect to a 
specific hardware driver...just don't bank too much on the "spurious 
interrupt" having anything significant to do with it.

D. Stimits, stimits AT attbi.com