spin_lock using kernel-smp-2.4.20-3.4

I have been using Aurora for quite some time now, a single
SuperSparc-(II) firewall SS20 (sun4m), a dual SuperSparc-(II) test
compile machine for linux-sparc gcc (which I'd rather have running my
quad Ross HyperSparc) and an single CPU UltraSparc I test compile
machine for linux64-sparc gcc. They all the run kernel-2.4.20-3.4sparc
kernel, in their respective flavour...

The dual sun4m system hangs quite often (say once a day), and it's a
spin_lock all the time...

Today, it looked like this:

spin_lock(f3d1e73c) CPU#0 stuck at f0086f44, owner PC(fbe8c400:PC(0)
spin_lock(f3d1e73c) CPU#1 stuck at f002cbbc, owner PC(fbe8c400:PC(0)

and, although they're not oopses, running ksymoops I get this:

[chj@sparky chj]$ ksymoops oops.file
ksymoops 2.4.4 on sparc 2.4.20-3.4sparcsmp.  Options used
     -V (default)
     -k /proc/ksyms (default)
     -l /proc/modules (default)
     -o /lib/modules/2.4.20-3.4sparcsmp/ (default)
     -m /boot/System.map-2.4.20-3.4sparcsmp (default)
 
Warning: You did not tell me where to find symbol information.  I will
assume that the log matches the kernel and modules that are running
right now and I'll use the default options above for symbol resolution.
If the current kernel and/or modules do not match the log, you can get
more accurate output by telling me the kernel version and where to find
map, modules, ksyms etc.  ksymoops -h explains the options.
 
Error (expand_objects): cannot stat(/lib/esp.o) for esp
ksymoops: No such file or directory
/usr/bin/find: /lib/modules/2.4.20-3.4sparcsmp/build: No such file or directory
Error (pclose_local): find_objects pclose failed 0x100
Warning (map_ksym_to_module): cannot match loaded module esp to a unique module
object.  Trace may not be reliable.
spin_lock(f3d1e73c) CPU#0 stuck at f0086f44, owner PC(fbe8c400:PC(0)
Using defaults from ksymoops -t elf32-sparc -a sparc
spin_lock(f3d1e73c) CPU#1 stuck at f002cbbc, owner PC(fbe8c400:PC(0)
Warning (Oops_read): Code line not seen, dumping what data is available
 
>>PC;  f0086f44 <task_dumpable+10/40>   <=====
>>PC;  fbe8c400 <end+bbc7fa8/e048c08>   <=====
Trace; f3d1e73c <end+3a5a2e4/e048c08>
>>PC;  f002cbbc <here+1c/13c>   <=====
>>PC;  fbe8c400 <end+bbc7fa8/e048c08>   <=====
Trace; f3d1e73c <end+3a5a2e4/e048c08>
 
 
3 warnings and 2 errors issued.  Results may not be reliable.
[chj@sparky chj]$

Not of much help I guess... Is there anything I can do to further look
into what/where things go wrong?

TIA,

/ChJ