Well, I was using my Sun-3/110 to attack the ffs_alloccgblk panic, and
when I was working on a vnd filesystem I got

panic: locking against myself
Stopped at      _Debugger+0x6:  unlk    a6
db> trace
_Debugger(e01aa84,e0875aa,eda7934,10,eda7940) + 6
_panic(e0875aa,e5758f0,e75e7d4,e8d4000,eda79a8) + 34
_ufs_lock(eda79a0) + 64
_vndstrategy(e75e7d4,eda79d4,e0265ca,eda79cc,2004) + f6
_spec_strategy(eda79cc) + 24
_bwrite(e75e7d4,eda79f4,e0266e2,eda79ec,e0bdba0) + b8
_vn_bwrite(eda79ec,e0bdba0,e75e7d4,eda7a08,e026c36) + c
_bawrite(e75e7d4) + 36
_getnewbuf(0,0) + 7a
_getblk(e5ab400,ffffcff4,2000,0,0) + c4
_ufs_bmaparray(e5ab400,31f0,eda7b28,0,0) + 15a
_ufs_bmap(eda7b0c) + 3c
_vndstrategy(e75c104,eda7b64,e0265ca,eda7b5c,2004) + 13e
_spec_strategy(eda7b5c) + 24
_bwrite(e75c104,eda7b84,e0266e2,eda7b7c,e0bdba0) + b8
_vn_bwrite(eda7b7c,e0bdba0,e75c104,eda7b98,e026c36) + c
_bawrite(e75c104) + 36
_getnewbuf(0,0) + 7a
_getblk(e5a4400,0,1400,0,0) + c4
_bread(e5a4400,0,1400,ffffffff,eda7c28) + 20
_ffs_blkatoff(eda7ca0) + 82
_ufs_lookup(eda7d04) + 3f0
_lookup(eda7ea0) + 234
_namei(eda7ea0) + 16a
_check_exec(e58e800,eda7ee8,40,3f,0) + 24
_sys_execve(e58e800,eda7f84,eda7f7c) + c2
_syscall(3b) + 13a
_trap0() + e
db> c
syncing disks... panic: locking against myself
Stopped at      _Debugger+0x6:  unlk    a6
db> c
dumping not supported yet :)
Kernel rebooting...
Boot: sd(0,0,0)
Invalid Page Bus Error:
  Vaddr: 0E58E7FF, Paddr: 000007FF, Type 0, Read, FC 5, Size 1 at 0x00004014
>

I'm not going to have time to look at this in any detail today.  I hope
someone has some idea what's wrong....

					der Mouse

			    mouse@collatz.mcrcim.mcgill.edu