I am having some weird problems on a kernel from a source supped last tuesday.
The kernel version is NetBSD/Atari1.4ZD. What I see happening is that all of
a sudden, everything stops working. A getty still echo's characters, but it
isn't really handling them.
If I let it dump into the debugger (so the keyboard interrupt still works), I
get the following stack trace:

Stopped at   _cpu_Debugger+0x6:      unlk    a6
db> t
_cpu_Debugger(0,0,0,164448,2b084b0) + 6
_kbdintr(2000) + 5c
mfp_kbd(?)
_mi_switch(2b084b0) + 10
_ltsleep(164af8,28,5146e,0,0) + 156
_sched_sync(2b084b0) + 1fc
_proc_trampoline() + 2

'ps' says:

db> ps

 PID             PPID       PGRP        UID S   FLAGS          COMMAND    WAIT
 273              229        229          0 3     0x4            isdnd vmmaplk
 242                1        242          0 3  0x4084            getty nanosle
 241                1        241          0 3  0x4086            getty   ttyin
 240                1        240          0 3  0x4086              ksh   pause
 239                1        239          0 3  0x4086              ksh   pause
 229                1        229          0 3    0x84            isdnd  select
 227                1        227          0 3    0x84            sshd1  select
 221                1        221          0 3    0x84            inetd  select
 212                1        212          0 3    0x84              lpd  select
 200                1        200          0 3   0x184             cron nanosle
 198                1        198          0 3    0x84           update   pause
 161                1        161          0 3    0x84          portmap  select
 157                1        157          0 3    0x84          syslogd  select
 54                 1         54          0 3    0x84        mount_mfs  mfsidl
 44                 1         44          0 3    0x84         slattach   pause
 37                 1         37          0 3    0x84           update   pause
 4                  0          0          0 3 0x20204          ioflush  syncer
 3                  0          0          0 3 0x20204           reaper vmmaplk
 2                  0          0          0 3 0x20204       pagedaemon daemon_
 1                  0          1          0 3  0x4084             init   pause
 0                 -1          0          0 3 0x20204          swapper schedul
 254              240        254          0 6  0x6006              vim        
 262              239        262          0 6  0x6006              scp        
 263                1        262          0 6  0x6006              ssh        

There is no current process...
Then I tried 'show map' but after the first entry everything hangs solid and
I had the hard reset.

db> show map
MAP 0xa93b6: [0x34006433->0x643200]
   #ent=1316310614, sz=18663, ref=3680366, version=1502108032, flags=0x7034d08c

Does anybody have an idea of what is going on here and how I can debug this?
The system seems to be pretty instable. I had multiple hangs of the time above
within an hour or 2. The last kernel that runs pretty stable (the one I tried
to upgrade from ;-) is NetBSD 1.4X.

Leo.