I was using emacs to edit a file in cfs, with the plaintext in coda.
emacs makes symlinks, and cfs makes symlinks to store the IV for the
file.

I have seen similar problems with refcounting in the coda kernel code
before.
I'll look into this more some time, and certainly if it recurs, but
any clues appreciated.

(gdb) target kcore netbsd.0.core
panic: vput: ref cnt
#0  0x1 in ?? ()
(gdb) bt
#0  0x1 in ?? ()
#1  0xc02b35b3 in cpu_reboot ()
#2  0xc01f1fa3 in panic ()
#3  0xc020cb61 in vput ()
#4  0xc020b651 in lookup ()
#5  0xc016b04d in coda_symlink ()
#6  0xc0213ab2 in VOP_SYMLINK ()
#7  0xc021091d in sys_symlink ()
#8  0xc02b9eeb in syscall_plain ()
#9  0xc0100d4a in syscall1 ()
can not access 0xbfbfc84c, invalid translation (invalid PDE)
can not access 0xbfbfc84c, invalid translation (invalid PDE)
Cannot access memory at address 0xbfbfc84c