(Replying to my own mail here)
	I've just had this happen again (several times in fact) - this 
	time it was in stat() rather than lstat() but otherwise the stack
	trace was the same.
	I'm compiling a DDB/DIAGNOSTIC/DEBUG kernel now.

	I've tried going back to my previous -current kernel which was
	workign fine on another machine but it now panics under load
	too (arrg - its the start of term and I have a lot of unhappy users
	on this one :)

	If nothing blindingly obvious grabs me from the DEBUG kernel I guess
	I'll have to transfer everything back to SunOS here :(
	(I wish to hell I'd newfs'ed the disks in old 4.2 format - arrg :)

		David/abs

 D.K.Brownlee@city.ac.uk (MIME) +44 171 477 8186  {post,host}master  (abs)
Network Analyst, UCS, City University, Northampton Square, London EC1V 0HB.
        <<< Monochrome - Largest UK Internet BBS - telnet mono.org >>>
>=- Microsoft: Abort and Retry Cancel -or- NetBSD: http://www.netbsd.org -=<

On Sun, 1 Oct 1995, David Brownlee wrote:

> 	I've just installed yesterdays -current on a Sparc 2 & was doing
> 	some pretty intensive disk activity (3 or 4 parallel tars on 3 local
> 	disks & 1 nfs mount) when it paniced. (It was also serving a dozen
> 	connections from monochrome (a homebrew BBS system), which would
> 	ad to the load a little.
> 
> 	It nicely saved the crashdump... any idea what I should be doing 
> 	next? :) 
> 
> 	Thanks!
> 		David
> 
> (no debugging symbols found)...
> panic: free vnode isn't
> #0  0xf8007730 in snapshot ()
> (kgdb) bt
> #0  0xf8007730 in snapshot ()
> #1  0xf8007738 in snapshot ()
> #2  0xf80afa74 in boot ()
> #3  0xf801bb40 in panic ()
> #4  0xf80345d4 in getnewvnode ()
> #5  0xf808846c in ffs_vget ()
> #6  0xf808a798 in ufs_lookup ()
> #7  0xf8033ab4 in lookup ()
> #8  0xf8033560 in namei ()
> #9  0xf8038564 in lstat ()
> #10 0xf80b5e1c in syscall ()
> #11 0xf8006530 in trapbase ()
> (kgdb)
> 
> 
> dmesg:	(sd3 is an old 1Gb SCSI1 disk in a sun shoebox (with the bizarre
> 	tapedrive from hell) that I was using to copy data from (the disk not
> 	the tapedrive :)
> 
> NetBSD 1.0A (_SUN4C_) #0: Sat Sep 30 16:04:06 BST 1995
>     
> monoadm@gluon.mono.org:/mono/netbsd/arch/sparc/sys/arch/sparc/compile/_SUN4C_
> real mem = 33419264
> avail mem = 30081024
> using 407 buffers containing 1667072 bytes of memory
> bootpath: /sbus0/esp@0,800000/sd@0,0
> mainbus0 (root)
> cpu0 at mainbus0: SUNW,Sun 4/75 (RT601 or L64811 v2 @ 40 MHz, TMS390C602A 
> FPU)
> cpu0: cache chip bug; trap page uncached
> cpu0: 65536 byte write-through, 32 bytes/line, hw flush cache enabled
> memreg0 at mainbus0 ioaddr 0xf4000000
> clock0 at mainbus0 ioaddr 0xf2000000: mk48t02 (eeprom)
> timer0 at mainbus0 ioaddr 0xf3000000
> auxreg0 at mainbus0 ioaddr 0xf7400003
> zs0 at mainbus0 ioaddr 0xf1000000 pri 12, softpri 6
> zs0a: console i/o
> zs1 at mainbus0 ioaddr 0xf0000000 pri 12, softpri 6
> audio0 at mainbus0 ioaddr 0xf7201000 pri 13, softpri 4
> sbus0 at mainbus0 ioaddr 0xf8000000: clock = 20 MHz
> le0 at sbus0 slot 0 offset 0xc00000 pri 5: hardware address 08:00:20:0e:8d:a4
> dma0 at sbus0 slot 0 offset 0x400000: rev 1+
> esp0 at sbus0 slot 0 offset 0x800000 pri 3: ESP100A 20Mhz, target 7
> scsibus0 at esp0
> esp0 targ 0 lun 0: <QUANTUM, PD700S, 3110> SCSI2 0/direct fixed
> sd0 at scsibus0: 668MB, 2448 cyl, 8 head, 69 sec, 512 bytes/sec
> esp0 targ 1 lun 0: <HITACHI, DK315C-10, J0H3> SCSI2 0/direct fixed
> sd1 at scsibus0: 1005MB, 2483 cyl, 11 head, 75 sec, 512 bytes/sec
> esp0(2,0): MSGIN failed; trying alt selection
> esp: resetting SCSI bus
> esp0: stray interrupt
> esp0 targ 2 lun 0: <FUJITSU, M2266S-512, 001F> SCSI2 0/direct fixed
> sd2 at scsibus0: 1029MB, 1658 cyl, 15 head, 84 sec, 512 bytes/sec
> esp0 targ 4 lun 0: <, , > SCSI0 0/direct fixed
> sd3 at scsibus0: drive offline
> fd at mainbus0 ioaddr 0xf7200000 not configured
> root on sd0a
> 
> 		David/abs
> 
>  D.K.Brownlee@city.ac.uk (MIME) +44 171 477 8186  {post,host}master  (abs)
> Network Analyst, UCS, City University, Northampton Square, London EC1V 0HB.
>         <<< Monochrome - Largest UK Internet BBS - telnet mono.org >>>
> >=- Microsoft: Abort and Retry Cancel -or- NetBSD: http://www.netbsd.org -=<
> 
>