Deadlocks with recent SMP current
Scott Long
scottl at samsco.org
Fri Aug 13 13:11:38 PDT 2004
Lukas Ertl wrote:
> On Fri, 13 Aug 2004, Robert Watson wrote:
>
>> will eventually get a solid hang. I tried it on a new SMP box with an
>> NMI
>> button I received yesterday but was unable to get into the debugger. I'm
>> in the process of de-obfuscating the NMI path to increase the chances of
>> successfully getting into the debugger and then I'll try again to see
>> what
>> I can figure out.
>
>
> I have an NMI-enabled SMP box too, and the only message I got when
> sending an NMI to the deadlocked system was 'kernel trap 12 with
> interrupts disabled', but nothing more.
>
> If you want me to test something, feel free to shout out.
>
> cheers,
> le
>
The NMI handler(s) try to do far too much and often get caught up in
mutexes. I've locally changed it to just call either kdb_backtrace() or
kdb_enter() and then reboot. We might want to consider looking for
a general solution for this in 5.3.
Scott
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