# cd /usr/obj/usr/src/sys/mykernel/
# kgdb kernel.debug /var/crash/vmcore.0
[GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.so: Unde                                                                             fined symbol "ps_pglobal_lookup"]
GNU gdb 6.1.1 [FreeBSD]
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-marcel-freebsd".

Unread portion of the kernel message buffer:
interrupt                   total
irq14: ata0                       325735
irq16: fxp1                            5
irq17: ath0                     50298459
irq18: wi0                       3904083
irq19: sis0 fxp0                20167051
cpu0: timer                    604044908
Total                   678740241
panic: watchdog timeout
Uptime: 3d11h53m45s
Dumping 223 MB (2 chunks)
  chunk 0: 1MB (159 pages) ... ok
  chunk 1: 223MB (57072 pages) 207 191 175 159 143 127 111 95 79 63 47 31 15

#0  doadump () at pcpu.h:165
165             __asm __volatile("movl %%fs:0,%0" : "=r" (td));
(kgdb) backtrace
#0  doadump () at pcpu.h:165
#1  0xc059c4ee in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:402
#2  0xc059c7a6 in panic (fmt=0xc081050d "watchdog timeout")
    at /usr/src/sys/kern/kern_shutdown.c:558
#3  0xc0571642 in watchdog_fire () at /usr/src/sys/kern/kern_clock.c:583
#4  0xc0571130 in hardclock (frame=0xc1f44780)
    at /usr/src/sys/kern/kern_clock.c:279
#5  0xc07a4631 in lapic_handle_timer (frame=
      {cf_vec = 0, cf_fs = 8, cf_es = 40, cf_ds = 40, cf_edi = -1040320488, cf_esi = -1040320512, cf_ebp = -890192676, cf_ebx = 0, cf_edx = 0, cf_ecx = -1041016416, cf_eax = 1000, cf_eip = -1063283195, cf_cs = 32, cf_eflags = 524818, cf_esp = -890192644, cf_ss = -1063305969}) at /usr/src/sys/i386/i386/local_apic.c:623
#6  0xc079eb30 in Xtimerint () at apic_vector.s:137
#7  0xc09f9605 in ?? ()
#8  0xcaf0bd04 in ?? ()
#9  0xc07a609f in cpu_idle () at /usr/src/sys/i386/i386/machdep.c:1134
Previous frame inner to this frame (corrupt stack?)
(kgdb) quit