(kgdb) bt
#0  __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:55
#1  doadump (textdump=<optimized out>) at /usr/src/sys/kern/kern_shutdown.c:396
#2  0xffffffff80c0653a in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:484
#3  0xffffffff80c069de in vpanic (fmt=<optimized out>,
    ap=ap@entry=0xfffffe00077a3d50) at /usr/src/sys/kern/kern_shutdown.c:923
#4  0xffffffff80c06813 in panic (fmt=<unavailable>)
    at /usr/src/sys/kern/kern_shutdown.c:847
#5  0xffffffff80a5f5ab in wd_timeout_cb (arg=0xffffffff811dd590)
    at /usr/src/sys/dev/watchdog/watchdog.c:260
#6  0xffffffff80c23a63 in softclock_call_cc (
    c=0xffffffff81c72418 <wd_pretimeo_handle>,
    cc=cc@entry=0xffffffff81cb3940 <cc_cpu>, direct=direct@entry=0)
    at /usr/src/sys/kern/kern_timeout.c:692
#7  0xffffffff80c23ec9 in softclock (arg=0xffffffff81cb3940 <cc_cpu>)
    at /usr/src/sys/kern/kern_timeout.c:812
#8  0xffffffff80bc646a in intr_event_execute_handlers (ie=0xfffff80003579b00,
    p=<optimized out>) at /usr/src/sys/kern/kern_intr.c:1169
#9  ithread_execute_handlers (ie=0xfffff80003579b00, p=<optimized out>)
    at /usr/src/sys/kern/kern_intr.c:1182
#10 ithread_loop (arg=arg@entry=0xfffff80003514360)
    at /usr/src/sys/kern/kern_intr.c:1270
#11 0xffffffff80bc31fe in fork_exit (callout=0xffffffff80bc6210 <ithread_loop>,
    arg=0xfffff80003514360, frame=0xfffffe00077a3f40)
    at /usr/src/sys/kern/kern_fork.c:1093
#12 <signal handler called>