Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address	= 0xffffffff83449abc
fault code		= supervisor read data, page not present
instruction pointer	= 0x20:0xffffffff80931c30
stack pointer	        = 0x28:0xfffffe02c796cad0
frame pointer	        = 0x28:0xfffffe02c796cae0
code segment		= base rx0, limit 0xfffff, type 0x1b
	    = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 5554 (chrome)
trap number		= 12
panic: page fault
cpuid = 1
KDB: stack backtrace:
#0 0xffffffff80963000 at kdb_backtrace+0x60
#1 0xffffffff80928125 at panic+0x155
#2 0xffffffff80d24f1f at trap_fatal+0x38f
#3 0xffffffff80d25238 at trap_pfault+0x308
#4 0xffffffff80d2489a at trap+0x47a
#5 0xffffffff80d0a782 at calltrap+0x8
#6 0xffffffff80d258bf at amd64_syscall+0x3bf
#7 0xffffffff80d0aa6b at Xfast_syscall+0xfb
Uptime: 4h50m54s
Dumping 761 out of 10213 MB:..3%..11%..21%..32%..42%..51%..61%..72%..82%..91%


(kgdb) list *0xffffffff80931c30
0xffffffff80931c30 is in syscall_thread_exit (/usr/src/sys/kern/kern_syscalls.c:99).
94	syscall_thread_exit(struct thread *td, struct sysent *se)
95	{
96		u_int32_t cnt, oldcnt;
97	
98		do {
99			oldcnt = se->sy_thrcnt;
100			if ((oldcnt & SY_THR_STATIC) != 0)
101				return;
102			cnt = oldcnt - SY_THR_INCR;
103		} while (atomic_cmpset_rel_32(&se->sy_thrcnt, oldcnt, cnt) == 0);
(kgdb) backtrace
#0  doadump (textdump=<value optimized out>) at pcpu.h:219
#1  0xffffffff80927da2 in kern_reboot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:452
#2  0xffffffff80928164 in panic (fmt=<value optimized out>) at /usr/src/sys/kern/kern_shutdown.c:759
#3  0xffffffff80d24f1f in trap_fatal (frame=<value optimized out>, eva=<value optimized out>) at /usr/src/sys/amd64/amd64/trap.c:865
#4  0xffffffff80d25238 in trap_pfault (frame=0xfffffe02c796ca20, usermode=<value optimized out>) at /usr/src/sys/amd64/amd64/trap.c:676
#5  0xffffffff80d2489a in trap (frame=0xfffffe02c796ca20) at /usr/src/sys/amd64/amd64/trap.c:440
#6  0xffffffff80d0a782 in calltrap () at /usr/src/sys/amd64/amd64/exception.S:232
#7  0xffffffff80931c30 in syscall_thread_exit (td=0xfffff801d939d000, se=0xffffffff83449a90) at /usr/src/sys/kern/kern_syscalls.c:95
#8  0xffffffff80d258bf in amd64_syscall (td=0xfffff801d939d000, traced=0) at subr_syscall.c:151
#9  0xffffffff80d0aa6b in Xfast_syscall () at /usr/src/sys/amd64/amd64/exception.S:391
#10 0x000000080f0e304a in ?? ()
(kgdb)