panic in recent 6-current

[Divacky Roman]

#22 0xc0493087 in softclock (dummy=0x0) at atomic.h:365
#23 0xc04768a3 in ithread_loop (arg=0xc1577480)
    at /usr/src/sys/kern/kern_intr.c:546
#24 0xc0475be9 in fork_exit (callout=0xc0476761 <ithread_loop>,
        arg=0xc1577480, frame=0xd3fc3d48) at /usr/src/sys/kern/kern_fork.c:790
#25 0xc057ef5c in fork_trampoline () at /usr/src/sys/i386/i386/exception.s:208


(all other frames are either ??? or from ddb)

I got this on ~12 hours old current later in boot after initializing pf and
before initializing usbd

roman