Panic on boot current amd64

>From current today after changes to /sys/sys/gtaskqueue.h (r312293) I get panic on boot.
reverting to r312235 boot ok

random: harvesting attach, 8 bytes (4 bits) from uhub9
ugen1.3: <Logitech USB Optical Mouse> at usbus1
kernel trap 12 with interrupts disabled


Fatal trap 12: page fault while in kernel mode
cpuid = 2; apic id = 02
fault virtual address	= 0x64
fault code		= supervisor read data, page not present
instruction pointer	= 0x20:0xffffffff80660449
stack pointer	        = 0x28:0xfffffe0466aa9010
frame pointer	        = 0x28:0xfffffe0466aa9030
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		= 60445 (ifconfig)
[ thread pid 60445 tid 100131 ]
Stopped at      grouptaskqueue_enqueue+0x19:    cmpl    $0,0x64(%rbx)
db> bt
Tracing pid 60445 tid 100131 td 0xfffff800088df500
grouptaskqueue_enqueue() at grouptaskqueue_enqueue+0x19/frame 0xfffffe0466aa9030
em_intr() at em_intr+0x8c/frame 0xfffffe0466aa9060
iflib_fast_intr() at iflib_fast_intr+0x2c/frame 0xfffffe0466aa9080
intr_event_handle() at intr_event_handle+0x9b/frame 0xfffffe0466aa90d0
intr_execute_handlers() at intr_execute_handlers+0x48/frame 0xfffffe0466aa9100
lapic_handle_intr() at lapic_handle_intr+0x3f/frame 0xfffffe0466aa9120
Xapic_isr1() at Xapic_isr1+0xb7/frame 0xfffffe0466aa9120
--- interrupt, rip = 0xffffffff809639ad, rsp = 0xfffffe0466aa91f0, rbp = 0xfffffe0466aa9200 ---
spinlock_exit() at spinlock_exit+0x2d/frame 0xfffffe0466aa9200
smp_rendezvous_cpus() at smp_rendezvous_cpus+0x272/frame 0xfffffe0466aa9270
smp_rendezvous() at smp_rendezvous+0x40/frame 0xfffffe0466aa92a0
counter_u64_alloc() at counter_u64_alloc+0x3e/frame 0xfffffe0466aa92c0
rtentry_zinit() at rtentry_zinit+0x11/frame 0xfffffe0466aa92e0
keg_alloc_slab() at keg_alloc_slab+0x1e3/frame 0xfffffe0466aa9350
keg_fetch_slab() at keg_fetch_slab+0x16e/frame 0xfffffe0466aa93a0
zone_fetch_slab() at zone_fetch_slab+0x9e/frame 0xfffffe0466aa93e0
zone_import() at zone_import+0x52/frame 0xfffffe0466aa9430
uma_zalloc_arg() at uma_zalloc_arg+0x450/frame 0xfffffe0466aa94a0
rtrequest1_fib() at rtrequest1_fib+0xfc/frame 0xfffffe0466aa95c0
rtinit() at rtinit+0x390/frame 0xfffffe0466aa9740
in_addprefix() at in_addprefix+0xef/frame 0xfffffe0466aa97b0
in_control() at in_control+0x9dc/frame 0xfffffe0466aa9850
ifioctl() at ifioctl+0xdcc/frame 0xfffffe0466aa98d0
kern_ioctl() at kern_ioctl+0x274/frame 0xfffffe0466aa9950
sys_ioctl() at sys_ioctl+0x13c/frame 0xfffffe0466aa9a20
amd64_syscall() at amd64_syscall+0x488/frame 0xfffffe0466aa9bb0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0466aa9bb0
--- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x4b194a, rsp = 0x7fffffffe478, rbp = 0x7fffffffe4d0 ---
db>