wapbl panic on new system with too much memory!

[Paul Goyette <paul%whooppee.com@localhost>]

I'm in the process of installing a new machine, and I'm getting a 
reproducible panic at boot time.
The machine is a Intel Core i7-6900 (8 cores, 16 threads, 3.2GHz) on an 
ASUS X99-E motherboard.  It is fully-populated with 8 x 16GB DDR4 DIMMs 
(for a total, yes, of 128GB!).
Basically, I cloned the hard drive of my other machine using dd, and 
then put the copy in the new machine, and booted.  It comes up fine in 
single-user mode.  However, shortly after typing ^D to the single-user 
shell, it fails a KASSERT at sys/kern/vfs_wapbl.c line 1088.  The 
following is manually transcribed:
	trap type 1 code 0 rip ffffffff80114cf5 cs8 rflags 246 cr2
	7ef4986dd3d0 ilevel 0 rsp fffffe90eb210b10

	ddb> bt

	breakpoint + 0x5
	vpanic + 0x140
	cd_play_msf (ie, end of panic()!)
	wapbl_add_buf + 0x134
	bdwrite + 0xbd
	ffs_update.part.3 + 0x1f0
	ffs_full_fsync + 0x187
	ffs_fsync + 0x4b
	VOP_FSYNC + 0x3e
	ffs_sync + 0xd0
	VFS_SYNC + 0x1c
	do_sys_sync + 0xb3
	sys_sync + 0x9
	syscall + 0x15b
	--- syscall number 36 ---

I have four file systems on the single hard drive, and all of them are 
mounted '-o log' (ie, wapbl enabled).
Upon reboot, I manually forced an fsck of all file systems via 'fsck 
-fp' and no issues were found.  I then did a sync;sync;sync without any 
problems.  But again, as soon as I ^D from the single-user shell, I got 
the same panic.
Anyone got any clues?


+------------------+--------------------------+------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:      |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org |
+------------------+--------------------------+------------------------+