LOR in kern_thread.c

I was playing with libkse and got the follow LOR:

lock order reversal
 1st 0xc6ce0aa8 sigacts (sigacts) _at_ /local/usr.src/sys/kern/subr_trap.c:248
 2nd 0xc6cbc250 process lock (process lock) _at_ /local/usr.src/sys/kern/kern_threa
d.c:1439
Stack backtrace:
backtrace(c04fd0b6,c6cbc250,c04f9a3a,c04f9a3a,c04fae7a) at backtrace+0x17
witness_lock(c6cbc250,8,c04fae7a,59f,c6bb8130) at witness_lock+0x692
_mtx_lock_flags(c6cbc250,0,c04fae7a,59f,c6cbc1e4,2,0,0,0) at _mtx_lock_flags+0xb
2
thread_signal_add(c6bb8130,2,c04fa4c7,85e,280a1e20) at thread_signal_add+0xe1
postsig(2,0,c04fcb3a,f8,20800) at postsig+0x34f
ast(e98d9d48) at ast+0x41d
doreti_ast() at doreti_ast+0x17

-gordon