install/54805: uvm_fault during installation boot

[dhop%nwlink.com@localhost]

>Number:         54805
>Category:       install
>Synopsis:       uvm_fault during installation boot
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Dec 29 05:10:00 +0000 2019
>Originator:     David Hopper
>Release:        NetBSD-9.0 RC1
>Organization:
>Environment:
Not possible (kernel boot failure), but standard 9.0 RC1 UEFI installation image:  https://cdn.netbsd.org/pub/NetBSD/NetBSD-9.0_RC1/images/NetBSD-9.0_RC1-amd64-uefi-install.img.gz
>Description:
uvm_fault during initial installation boot on a Lenovo Thinkpad P53, seems to be related to the built-in camera module via uvideo.  NetBSD-current (~Dec. 26) boots just fine, not sure if a backport is required or desired.
[...]
[   4.6444651] sd0 at scsibus0 target 0 lun 0: <Kingston, DataTraveler 3.0, PMAP> disk removable
[   5.5965222] uvideo0 at uhub3 port 8 configuration 1 interface 0: Azurewave (0x13d3) Integrated Camera (0x56bc), rev 2.01/69.09, addr 3
[   5.5965222] uvm_fault(0xffffffff81585520, 0x0, 1) -> e
[   5.5965222] fatal page fault in supervisor mode
[   5.5965222] trap type 6 code 0 rip 0xffffffff80981654 cs 0x8 rflags 0x10246 cr2 0x36 ilevel 8 rsp 0xffffda8373a2ca90
[   5.5965222] curlwp 0xfffffdc68c423a60 pid 0.209 lowest kstack 0xffffda8373a2a2c0
kernel: page fault trap, code=0
Stopped in pid 0.209 (system) at        netbsd:vmem_alloc+0x3e: movq    0(%rax),
%rdi
db{0}> bt
vmem_alloc() at netbsd:vmem_alloc+0x3e
uvm_km_kmem_alloc() at netbsd:uvm_km_kmem_alloc+0x9c
kmem_intr_alloc() at netbsd:kmem_intr_alloc+0x6d
uvideo_unit_alloc_controls() at netbsd:uvideo_unit_alloc_controls+0x25
uvideo_attach() at netbsd:uvideo_attach+0x831
config_attach_loc() at netbsd:config_attach_loc+0x199
config_found_sm_loc() at netbsd:config_found_sm_loc+0x48
usbd_attachinterfaces() at netbsd:usbd_attachinterfaces+0x1b7
usbd_probe_and_attach() at netbsd:usbd_probe_and_attach+0x8c
xhci_new_device() at netbsd:xhci_new_device+0x6b3
usbd_new_device() at netbsd:usbd_new_device+0x52
uhub_explore() at netbsd:uhub_explore+0x25d
usb_discover.isra.0() at netbsd:usb_discover.isra.0+0x5b
usb_event_thread90 at netbsd:usb_event_thread+0x40
db{0}>

>How-To-Repeat:
Try booting NetBSD installation image on a ThinkPad P53 or possibly any laptop with the same Azurewave camera.
>Fix:
Current works fine with this camera module, possibly needs a backport unless doing so would be disruptive.

Current boot context looks like this; it apparently enumerates another camera instance where 9.0 RC1 bails out before/during enumeration:

[   3.403661] ses0 at scsibus0 target 0 lun 1: <SanDisk, SES Device, 1012> enclosure services fixed
[   3.403661] ses0: SCSI-3 SES Device
[   3.473814] run0: MAC/BBP RT5390 (rev 0x0502), RF RT5370 (MIMO 1T1R), address 00:ob:fu:sc:at:ed
[   4.445929] uvideo0 at uhub3 port 8 configuration 1 interface 0: Azurewave (0x13d3) Integrated Camera (0x56bc), rev 2.01/69.09, addr 2
[   4.445929] uvideo1 at uhub3 port 8 configuration 1 interface 2: Azurewave (0x13d3) Integrated Camera (0x56bc), rev 2.01/69.09, addr 2
[...]