I did nothing special when suddenly my freebsd rebooted:
Jul 10 17:16:06 nietykalni savecore: reboot after panic: page fault
Jul 10 17:16:06 nietykalni savecore: writing core to vmcore.0
--------------------------------------------------------------------------
nietykalni# cat /var/crash/info.0
Dump header from device /dev/ad1s1b
Architecture: i386
Architecture Version: 2
Dump Length: 267976704B (255 MB)
Blocksize: 512
Dumptime: Mon Jul 10 17:19:31 2006
Hostname: nietykalni.org
Magic: FreeBSD Kernel Dump
Version String: FreeBSD 6.0-RELEASE #1: Tue Mar 14 10:40:21 CET 2006
vandal@revival:/usr/obj/usr/src/sys/GENERIC-NIETYKALNI
Panic String: page fault
Dump Parity: 534305
Bounds: 0
Dump Status: good
-------------------------------------------------------------------------
nietykalni# kgdb kernel.debug /var/crash/vmcore.0
Unread portion of the kernel message buffer:
#0 doadump () at pcpu.h:165
165 __asm __volatile("movl %%fs:0,%0" : "=r" (td));
(kgdb) bt
#0 doadump () at pcpu.h:165
#1 0xc061f242 in boot (howto=260) at
/usr/src/sys/kern/kern_shutdown.c:399
#2 0xc061f4d8 in panic (fmt=0xc07f4c2a "%s")
at /usr/src/sys/kern/kern_shutdown.c:555
#3 0xc07b1f78 in trap_fatal (frame=0xd551cc18, eva=123)
at /usr/src/sys/i386/i386/trap.c:831
#4 0xc07b1ce3 in trap_pfault (frame=0xd551cc18, usermode=0, eva=123)
at /usr/src/sys/i386/i386/trap.c:742
#5 0xc07b1941 in trap (frame {tf_fs = 8, tf_es = -1030815704, tf_ds =
-1030815704, tf_edi =
-1030797440, tf_esi = -1042154576, tf_ebp = -716059468, tf_isp =
-716059580, tf_ebx = -1027664896,
tf_edx = -1030797440, tf_ecx = 4, tf_eax = 0, tf_trapno = 12, tf_err = 0,
tf_eip = -1067455388, tf_cs = 32, tf_eflags = 66182, tf_esp = -1039158768,
tf_ss = 0}) at
/usr/src/sys/i386/i386/trap.c:432
#6 0xc07a1a2a in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#7 0xc05fec64 in closef (fp=0xc1826120, td=0xc28f4780)
at /usr/src/sys/kern/kern_descrip.c:1876
#8 0xc05fc47d in close (td=0xc28f4780, uap=0x0)
at /usr/src/sys/kern/kern_descrip.c:1004
#9 0xc07b228f in syscall (frame {tf_fs = 59, tf_es = -1078001605, tf_ds =
-1078001605, tf_edi = 0,
tf_esi = 0, tf_ebp = -1077944344, tf_isp = -716059292, tf_ebx = 134934528,
tf_edx = 0, tf_ecx
0, tf_eax = 6, tf_trapno = 12, tf_err = 2, tf_eip = 144033747, tf_cs =
---Type <return> to continue, or q <return> to quit---
51, tf_eflags = 662, tf_esp = -1077944372, tf_ss = 59})
at /usr/src/sys/i386/i386/trap.c:976
#10 0xc07a1a7f in Xint0x80_syscall () at
/usr/src/sys/i386/i386/exception.s:200
#11 0x00000033 in ?? ()
Previous frame inner to this frame (corrupt stack?)
(...)
(kgdb) up
#4 0xc07b1ce3 in trap_pfault (frame=0xd551cc18, usermode=0, eva=123)
at /usr/src/sys/i386/i386/trap.c:742
742 trap_fatal(frame, eva);
(kgdb) p p->p_comm
$1 = "screen", '\0' <repeats 13 times>
(...)
(kgdb) up
#7 0xc05fec64 in closef (fp=0xc1826120, td=0xc28f4780)
at /usr/src/sys/kern/kern_descrip.c:1876
1876 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
Current language: auto; currently c
(kgdb) p vp
$2 = (struct vnode *) 0xc1e1fbb0
(kgdb) p vp-v_mount
No symbol "v_mount" in current context.
(kgdb) p vp->v_mount
$3 = (struct mount *) 0x0
(kgdb)
(...)