panic: No vop_lock(0xc2e95c30, 0xcd45f794) in GENERIC HEAD

This seems to be a Pty/devfs related problem:

VNASSERT failed
0xc2e95c30: tag none, type VBAD
    usecount 0, writecount 0, refcount 1 mountedhere 0
    flags (VI_DOOMED)
 VI_LOCKed
panic: No vop_lock(0xc2e95c30, 0xcd45f794)
cpuid = 0
KDB: enter: panic
[thread pid 7636 tid 100162 ]
Stopped at      kdb_enter+0x2b: nop
db> where
Tracing pid 7636 tid 100162 td 0xc2ba61b0
kdb_enter(c089bf32) at kdb_enter+0x2b
panic(c08c61d4,c2e95c30,cd45f794,c2e95c30,c08a4e9a) at panic+0x14b
VOP_LOCK_APV(0,cd45f794) at VOP_LOCK_APV+0x73
vn_lock(c2e95c30,2002,c2ba61b0,c2e95c30,2) at vn_lock+0xa8
vget(c2e95c30,2,c2ba61b0) at vget+0xba
devfs_allocv(c23ae980,c23d9000,cd45fb90,...) at devfs_allocv+0x37
devfs_lookupx(cd45f974,c23ce490,c0894142,...) at devfs_lookupx+0x4a6
devfs_lookup(cd45f974,c23f5000,0,cd45f990,...) at devfs_lookup+0x2d
VOP_LOOKUP_APV(c0923900,cd45f974) at VOP_LOOKUP_APV+0x87
lookup(cd45fb7c,c06c24ae,0,c2ba61b0,c08a5cf8) at lookup+0x402
namei(cd45fb7c,c089d8df,26e,c2ba61b0,cd45fa18) at namei+0x382
vn_open_cred(cd45fb7c,cd45fc7c,0,c376ea80,3) at vn_open_cred+0x277
vn_open(cd45fb7c,cd45fc7c,0,3,cd45fb10) at vn_open+0x1e
kern_open(c2ba61b0,bfbfe150,0,3,0) at kern_open+0xb9
open(c2ba61b0,cd45fd04,cd45fccc,c066ec40,c2ba61b0) at open+0x18
syscall(bfbf003b,ffff003b,bfbf003b,bfbfe15b,...) at syscall+0x27e

More info at:
http://people.freebsd.org/~pho/stress/log/cons195.html
-- 
Peter Holm