panic: mtx_lock() of spin mutex (null) _at_ /usr/src/sys/net/iflib.c:3716

This was running:

FreeBSD g1-215.catwhisker.org 12.0-CURRENT FreeBSD 12.0-CURRENT #156  r332399M/332400:1200061: Wed Apr 11 04:17:45 PDT 2018     root_at_g1-215.catwhisker.org:/common/S4/obj/usr/src/amd64.amd64/sys/CANARY  amd64

during boot, after updating from:

FreeBSD g1-215.catwhisker.org 12.0-CURRENT FreeBSD 12.0-CURRENT #155  r332354M/332357:1200061: Tue Apr 10 04:00:41 PDT 2018     root_at_g1-215.catwhisker.org:/common/S4/obj/usr/src/amd64.amd64/sys/CANARY  amd64

(My build machine, which uses an re((4) NIC, did not encounter the issue.)

It appears that r332389 is implicated.

...
Unread portion of the kernel message buffer:

__curthread () at ./machine/pcpu.h:230
230             __asm("movq %%gs:%1,%0" : "=r" (td)
(kgdb) #0  __curthread () at ./machine/pcpu.h:230
#1  doadump (textdump=3) at /usr/src/sys/kern/kern_shutdown.c:361
#2  0xffffffff80433f4c in db_fncall_generic (addr=<optimized out>, 
    rv=<optimized out>, nargs=<optimized out>, args=<optimized out>)
    at /usr/src/sys/ddb/db_command.c:609
#3  db_fncall (dummy1=<optimized out>, dummy2=<optimized out>, 
    dummy3=<optimized out>, dummy4=<optimized out>)
    at /usr/src/sys/ddb/db_command.c:657
#4  0xffffffff80433a99 in db_command (last_cmdp=<optimized out>, 
    cmd_table=<optimized out>, dopager=<optimized out>)
    at /usr/src/sys/ddb/db_command.c:481
#5  0xffffffff80433814 in db_command_loop ()
    at /usr/src/sys/ddb/db_command.c:534
#6  0xffffffff80436a3f in db_trap (type=<optimized out>, code=<optimized out>)
    at /usr/src/sys/ddb/db_main.c:250
#7  0xffffffff80b753e3 in kdb_trap (type=3, code=-61456, tf=<optimized out>)
    at /usr/src/sys/kern/subr_kdb.c:697
#8  0xffffffff80f7eaa8 in trap (frame=0xfffffe00004377a0)
    at /usr/src/sys/amd64/amd64/trap.c:548
#9  <signal handler called>
#10 kdb_enter (why=0xffffffff811df9d4 "panic", msg=<optimized out>)
    at /usr/src/sys/kern/subr_kdb.c:479
#11 0xffffffff80b2feda in vpanic (fmt=<optimized out>, ap=0xfffffe0000437910)
    at /usr/src/sys/kern/kern_shutdown.c:826
#12 0xffffffff80b2fca0 in kassert_panic (
    fmt=0xffffffff811dadca "mtx_lock() of spin mutex %s _at_ %s:%d")
    at /usr/src/sys/kern/kern_shutdown.c:723
#13 0xffffffff80b0ec93 in __mtx_lock_flags (c=0xfffff80008c85d88, opts=0, 
    file=0xffffffff81113c90 "/usr/src/sys/net/iflib.c", line=<optimized out>)
    at /usr/src/sys/kern/kern_mutex.c:246
#14 0xffffffff80c466e1 in _task_fn_admin (context=0xfffff80008c85c00)
    at /usr/src/sys/net/iflib.c:3716
#15 0xffffffff80b73849 in gtaskqueue_run_locked (queue=0xfffff80008489500)
    at /usr/src/sys/kern/subr_gtaskqueue.c:331
#16 0xffffffff80b735c8 in gtaskqueue_thread_loop (arg=<optimized out>)
    at /usr/src/sys/kern/subr_gtaskqueue.c:506
#17 0xffffffff80af0064 in fork_exit (
    callout=0xffffffff80b73540 <gtaskqueue_thread_loop>, 
    arg=0xfffffe0844223008, frame=0xfffffe0000437ac0)
    at /usr/src/sys/kern/kern_fork.c:1039
#18 <signal handler called>
(kgdb) 

If the dump would be useful, I can put it up for access.

Peace,
david
-- 
David H. Wolfskill				david_at_catwhisker.org
Well, what did you EXPECT from Trump?  He has a history of breaking promises.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.