Almost instant crasj after boot, 100% reproducable, version from middle of summer works

Hello freebsd-current,

 I have "home router" based on Intel MoBo with integrated Arom D2500 CPU.
 It boots and works fine on -CURRENT r285355 (it is ~11 of Jun 2015).

 But several latest revisions (I've tried r288145 month ago and now r289874)
crashes almost instantly after boot. It is 100% reproducible and didn't
changed for last month.

 Crash looks like this:

....
uhub4: 8 ports with 8 removable, self powered
ugen4.2: <JetFlash> at usbus4
umass0: <JetFlash Mass Storage Device, class 0/0, rev 2.00/1.41, addr 2> on usbus4
Root mount waiting for: usbus4
Trying to mount root from ufs:/dev/ufs/gws1a [ro]...
mountroot: waiting for device /dev/ufs/gws1a ...
da0 at umass-sim0 bus 0 scbus0 target 0 lun 0
da0: <JetFlash TS4GJFV35 8.07> Removable Direct Access SCSI-2 device
da0: Serial Number E8FT11YH
da0: 40.000MB/s transfers
da0: 3899MB (7987198 512 byte sectors)
da0: quirks=0x2<NO_6_BYTE>
random: unblocking device.
sysctl: kern.ipc.nmbclusters=65536 at line 15: Invalid argument
Setting hostuuid: fafea46a-1adb-e111-b48f-00e04cb00c04.
Setting hostid: 0x5084ca4a.
No suitable dump device was found.
Starting file system checks:
/dev/ufs/gws1a: FILE SYSTEM CLEAN; SKIPPING CHECKS
/dev/ufs/gws1a: clean, 642471 free (471 frags, 80250 blocks, 0.0% fragmentation)
/dev/ufs/gws3: FILE SYSTEM CLEAN; SKIPPING CHECKS
/dev/ufs/gws3: clean, 15292 free (28 frags, 1908 blocks, 0.2% fragmentation)
Mounting local file systems:.
Setting hostname: gateway.home.serebryakov.spb.ru.
Setting up harvesting:[UMA],[FS_ATIME],SWI,INTERRUPT,NET_NG,NET_ETHER,NET_TUN,MOUSE,KEYBOARD,ATTACH,CACHED
Feeding entropy:eval: cannot create /entropy: Read-only file system
ath_hal_reg_write: reg=0x000080e0, val=0xffffffff, pm=1
ath_hal_reg_write: reg=0x000080e4, val=0x0000ffff, pm=1
wlan0: Ethernet address: 00:15:6d:85:5f:fc
Created wlan(4) interfaces: wlan0.
Created clone interfaces: gif0.
em0: link state changed to UP
em0: link state changed to DOWN
ifconfig: NONE: bad value
vlan0: changing name to 'skynet'
vlan1: changing name to 'eltel'
Starting hostapd.
Configuration file: /etc/hostapd-wlan0.conf
Line 8: DEPRECATED: 'dump_file' configuration variable is not used anymore
Using interface wlan0 with hwaddr 00:15:6d:85:5f:fc and ssid "home.serebryakov.spb.ru"
wlan0: interface state UNINITIALIZED->ENABLED
wlan0: AP-ENABLED
kernel trap 9 with interrupts disabled


Fatal trap 9: general protection fault while in kernel mode
cpuid = 0; apic id = 00
instruction pointer     = 0x20:0xffffffff805190b6
stack pointer           = 0x28:0xfffffe012260e7d0
frame pointer           = 0x28:0xfffffe012260e8c0
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = resume, IOPL = 0
current process         = 16 (syncer)
trap number             = 9
panic: general protection fault
cpuid = 0
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe012260e470
vpanic() at vpanic+0x182/frame 0xfffffe012260e4f0
panic() at panic+0x43/frame 0xfffffe012260e550
trap_fatal() at trap_fatal+0x351/frame 0xfffffe012260e5b0
trap() at trap+0x6d8/frame 0xfffffe012260e710
calltrap() at calltrap+0x8/frame 0xfffffe012260e710
--- trap 0x9, rip = 0xffffffff805190b6, rsp = 0xfffffe012260e7e0, rbp = 0xfffffe012260e8c0 ---
sched_add() at sched_add+0x116/frame 0xfffffe012260e8c0
intr_event_schedule_thread() at intr_event_schedule_thread+0xae/frame 0xfffffe012260e8f0
intr_event_handle() at intr_event_handle+0xe2/frame 0xfffffe012260e940
intr_execute_handlers() at intr_execute_handlers+0x48/frame 0xfffffe012260e970
lapic_handle_intr() at lapic_handle_intr+0x3f/frame 0xfffffe012260e990
Xapic_isr1() at Xapic_isr1+0xb7/frame 0xfffffe012260e990
--- interrupt, rip = 0xffffffff8071eaad, rsp = 0xfffffe012260ea60, rbp = 0xfffffe012260ea70 ---
spinlock_exit() at spinlock_exit+0x2d/frame 0xfffffe012260ea70
sleepq_timedwait() at sleepq_timedwait+0xd3/frame 0xfffffe012260eaa0
_cv_timedwait_sbt() at _cv_timedwait_sbt+0x1a0/frame 0xfffffe012260eb10
sched_sync() at sched_sync+0x6b6/frame 0xfffffe012260ebb0
fork_exit() at fork_exit+0x75/frame 0xfffffe012260ebf0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe012260ebf0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
Uptime: 14s

-- 
Best regards,
 Lev                          mailto:lev_at_FreeBSD.org