login: panic: trying to free NULL pointer
_kfree() at _kfree+0x558 0xffffffff806583d8 
_kfree() at _kfree+0x558 0xffffffff806583d8 
ng_fec_constructor() at ng_fec_constructor+0x3ae 0xffffffff8263f44e 
ng_mkpeer() at ng_mkpeer+0x4c 0xffffffff82600ebc 
ng_generic_msg() at ng_generic_msg+0x415 0xffffffff82601835 
ng_send_msg() at ng_send_msg+0xf1 0xffffffff82602241 
Debugger("panic")
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>