Scheduling deadlock on alpha?

[Garance A Drosihn]

At 9:58 PM -0800 2/15/04, Kris Kennaway wrote:
>One of the alpha package machines seems to have deadlocked; no
>processes are running, but the kernel itself responds to pings,
>and I can break to DDB:   ...etc...
>


>WITNESS was not enabled, and the machines are running
>
>FreeBSD axp1.FreeBSD.org 5.2-CURRENT FreeBSD 5.2-CURRENT #0: Wed Jan 
>21 13:30:26 PST 2004 
>kris at bento.FreeBSD.org:/local0/obj/alpha/a/asami/portbuild/alpha/src-client/sys/NETBOOT 
>alpha
>
>Scheduler is 4BSD.

Hmm.  Interesting.  UP or SMP?

As an interesting coincidence, I had my dual-Athlon machine lock
up on me at about 5am on Sunday.  I didn't realize it was down
until I needed to use that machine for something, so I just
rebooted the machine without doing much investigation.  I had to
turn the machine off and back on to get it's attention (ctrl-alt-
delete was ignored).

WITNESS is not enabled, and the machine is running:

FreeBSD santropez.netel.rpi.edu 5.2-CURRENT FreeBSD 5.2-CURRENT #0: 
Wed Jan 21 23:28:30 EST 2004 
root at santropez.netel.rpi.edu:/usr/obj/usr/src/sys/Dual-Athlon2k  i386

The machine had run continuously from the time I did that last
installworld/installkernel, without any reboots.  It was running
some Folding at Home clients, so it would have racked up a lot of CPU
time.  Other than those clients, it should have been pretty idle for
a few hours before it hung up.  It NFS-exports some directories to
another system, but that other system did not have the directories
mounted at the time of the crash.

I really doubt it's related, but it is interesting that both machines
happen to have kernels from the same day...

-- 
Garance Alistair Drosehn            =   gad at gilead.netel.rpi.edu
Senior Systems Programmer           or  gad at freebsd.org
Rensselaer Polytechnic Institute    or  drosih at rpi.edu