panic: getnewvnode: free vnode isn't

This is on an alpha -CURRENT kernel from March 6.

Kris

panic: getnewvnode: free vnode isn't
at line 740 in file /a/asami/portbuild/alpha/src-client/sys/kern/vfs_subr.c
Stack backtrace:
db_print_backtrace() at db_print_backtrace+0x18
backtrace() at backtrace+0x2c
__panic() at __panic+0x150
getnewvnode() at getnewvnode+0x3e0
ffs_vget() at ffs_vget+0xac
ufs_lookup() at ufs_lookup+0xd90
ufs_vnoperate() at ufs_vnoperate+0x2c
vfs_cache_lookup() at vfs_cache_lookup+0x37c
ufs_vnoperate() at ufs_vnoperate+0x2c
lookup() at lookup+0x4ec
namei() at namei+0x330
lstat() at lstat+0x50
syscall() at syscall+0x36c
XentSys() at XentSys+0x64
--- syscall (190) ---
--- user mode ---