With sources updated about an hour ago (but happens the same with my overnight GENERIC as well), I get
--
----...
root file system type: ffs
fatal page fault in supervisor mode
trap type 6 code 0 rip ffffffff804fdd69 cs 8 rflags 10202 cr2 4a8 ilevel 4 rsp fffffe810e752b30
curlwp 0xfffffe823b744420 pid 0.3 lowest kstack 0xfffffe810e74f000
kernel: page fault trap, code=0
Stopped in pid 0.3 (system) at netbsd:mutex_owned+0x9: movq 0(%rdi),%rax
db{0}> bt
mutex_owned() at netbsd:mutex_owned+0x9
uhci_device_ctrl_done() at netbsd:uhci_device_ctrl_done+0x42
usb_transfer_complete() at netbsd:usb_transfer_complete+0x2d9
uhci_idone() at netbsd:uhci_idone+0x1e1
uhci_softintr() at netbsd:uhci_softintr+0x1a2
usb_soft_intr() at netbsd:usb_soft_intr+0x24
softint_dispatch() at netbsd:softint_dispatch+0xd9
DDB lost frame for netbsd:Xsoftintr:+0x4f, trying 0xfffffe810e752d70
Xsoftintr() at netbsd:Xsoftintr+0x4f
--- interrupt ---
0:
db{0}>
on a ThinkPAD T61p (which otherwise runs -current very well).
The above is taken from a screenshot, I did check it.
On the same userland a kernel from 07/01/2013 works fine.
Chavdar