I was in the middle of building the net/wireshark package, and my
AlphaPC 164 running 4.99.9 locked up. It no longer responds to pings,
and the only thing that I can do on the serial console is break to ddb:

Stopped in pid 8.1 (pagedaemon) at      netbsd:cpu_Debugger+0x4:        ret     zero,(ra)
db> t
cpu_Debugger() at netbsd:cpu_Debugger+0x4
comintr() at netbsd:comintr+0x7f0
alpha_shared_intr_dispatch() at netbsd:alpha_shared_intr_dispatch+0x6c
sio_iointr() at netbsd:sio_iointr+0x3c
interrupt() at netbsd:interrupt+0x1e4
XentInt() at netbsd:XentInt+0x1c
--- interrupt (from ipl 1) ---
nfs_timer() at netbsd:nfs_timer+0x1bc
softclock() at netbsd:softclock+0x2fc
hardclock() at netbsd:hardclock+0x3e4
interrupt() at netbsd:interrupt+0x9c
XentInt() at netbsd:XentInt+0x1c
--- interrupt (from ipl 0) ---
uvmpdpol_balancequeue() at netbsd:uvmpdpol_balancequeue+0xa0
uvm_pageout() at netbsd:uvm_pageout+0x454
exception_return() at netbsd:exception_return
--- root of call graph ---
db> c
[ break ]
Stopped in pid 8.1 (pagedaemon) at      netbsd:cpu_Debugger+0x4:        ret     zero,(ra)
db> t
cpu_Debugger() at netbsd:cpu_Debugger+0x4
comintr() at netbsd:comintr+0x7f0
alpha_shared_intr_dispatch() at netbsd:alpha_shared_intr_dispatch+0x6c
sio_iointr() at netbsd:sio_iointr+0x3c
interrupt() at netbsd:interrupt+0x1e4
XentInt() at netbsd:XentInt+0x1c
--- interrupt (from ipl 0) ---
uvmpd_trylockowner() at netbsd:uvmpd_trylockowner+0x4
uvmpd_trydropswap() at netbsd:uvmpd_trydropswap+0x44
uvmpdpol_balancequeue() at netbsd:uvmpdpol_balancequeue+0x138
uvm_pageout() at netbsd:uvm_pageout+0x454
exception_return() at netbsd:exception_return
--- root of call graph ---
db> c
[ break ]
Stopped in pid 8.1 (pagedaemon) at      netbsd:cpu_Debugger+0x4:        ret     zero,(ra)
db> t
cpu_Debugger() at netbsd:cpu_Debugger+0x4
comintr() at netbsd:comintr+0x7f0
alpha_shared_intr_dispatch() at netbsd:alpha_shared_intr_dispatch+0x6c
sio_iointr() at netbsd:sio_iointr+0x3c
interrupt() at netbsd:interrupt+0x1e4
XentInt() at netbsd:XentInt+0x1c
--- interrupt (from ipl 0) ---
uvmpdpol_balancequeue() at netbsd:uvmpdpol_balancequeue+0x80
uvm_pageout() at netbsd:uvm_pageout+0x454
exception_return() at netbsd:exception_return
--- root of call graph ---
db>

So it looks like it might be stuck in uvmpdpol_balancequeue().

-- 
Name: Dave Huang         |  Mammal, mammal / their names are called /
INet: khym@azeotrope.org |  they raise a paw / the bat, the cat /
FurryMUCK: Dahan         |  dolphin and dog / koala bear and hog -- TMBG
Dahan: Hani G Y+C 31 Y++ L+++ W- C++ T++ A+ E+ S++ V++ F- Q+++ P+ B+ PA+ PL++