Panic: GPF in kernel mode in fork_exit() (prior to FS mouont)

This was the "smoke test" boot after building:

FreeBSD  11.0-CURRENT FreeBSD 11.0-CURRENT #253  r291193M/291193:1100090: Mon Nov 23 04:43:34 PST 2015     root_at_g1-252.catwhisker.org:/common/S4/obj/usr/src/sys/CANARY  amd64

and (as noted), it happened fairly early in the boot sequence --
before the file systems were mounted, but after the device probes.

It also affected my build machine (same source revision) the same way.

The most recent successful head built & booted on the machine was:

FreeBSD g1-252.catwhisker.org 11.0-CURRENT FreeBSD 11.0-CURRENT #252  r291159M/291159:1100090: Sun Nov 22 05:16:34 PST 2015     root_at_localhost:/common/S4/obj/usr/src/sys/CANARY  amd64


I was able to capture a crash dump (by issuing "panic" at the "db>
" prompt); I've copied the vmcore.8 & core.txt.8 to
<http://www.catwhisker.org/~david/FreeBSD/head/>.  Here's an excerpt from
the core.txt.8:

...
SMP: passed TSC synchronization test
TSC timecounter discards lower 1 bit(s)
Timecounter "TSC-low" frequency 1396804168 Hz quality 1000
WARNING: WITNESS option enabled, expect reduced performance.
WARNING: DIAGNOSTIC option enabled, expect reduced performance.
Expensive timeout(9) function: 0xffffffff808830d0(0xffffffff81761898) 0.004704835 s
battery0: battery initialization done, tried 1 times
GEOM: new disk cd0
GEOM_PART: partition 1 on (diskid/DISK-W200TLZD, MBR) is not aligned on 4096 bytes
GEOM_PART: partition 2 on (diskid/DISK-W200TLZD, MBR) is not aligned on 4096 bytes
GEOM_PART: partition 3 on (diskid/DISK-W200TLZD, MBR) is not aligned on 4096 bytes
start_init: trying /sbin/init


Fatal trap 9: general protection fault while in kernel mode
cpuid = 6; apic id = 06
instruction pointer	= 0x20:0xffffffff809b049e
stack pointer	        = 0x28:0xfffffe06015a2a70
frame pointer	        = 0x28:0xfffffe06015a2ab0
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 1 (init)
Uptime: 3s
....

I'm happy to test possible fixes.

Peace,
david
-- 
David H. Wolfskill				david_at_catwhisker.org
Those who would murder in the name of God or prophet are blasphemous cowards.

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