"panic: vrele: negative ref cnt" on RELENG_5

[Kris Kennaway]

An amd64 machine I updated 5 days ago panicked with this at reboot
time:

Waiting (max 60 seconds) for system process `vnlru' to stop...done
Waiting (max 60 seconds) for system process `bufdaemon' to stop...done
Waiting (max 60 seconds) for system process `syncer' to stop...
Syncing disks, vnodes remaining...1 1 1 0 0 done
No buffers busy after final sync
panic: vrele: negative ref cnt
kdb_enter() at kdb_enter+0x2f
panic() at panic+0x1d2
vrele() at vrele+0x1ec
ffs_unmount() at ffs_unmount+0x182
dounmount() at dounmount+0x171
vfs_unmountall() at vfs_unmountall+0x50
boot() at boot+0x809
reboot() at reboot+0x3d
syscall() at syscall+0x4ab
Xfast_syscall() at Xfast_syscall+0xa8
--- syscall (55, FreeBSD ELF64, reboot), rip = 0x20076d76c, rsp = 0x7fffffffebb8, rbp = 0x1b0ab ---

Kris

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-amd64/attachments/20040929/cfe9e83f/attachment.bin