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

[Andrew Gilmore]

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?

Andrew