usb panic 9.99.81 attaching/detaching Garmin watch

[David Brownlee <abs%absd.org@localhost>]

From
NetBSD forsaken.absd.org 9.99.81 NetBSD 9.99.81 (GENERIC) #0: Thu Mar
11 15:27:40 UTC 2021
mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC
amd64

Reasonably reproducible (enough that I'm no longer attaching the cable
to my work machine :)

Tail end of dmesg from unplugging after booting with device attached:

sd1: detached
scsibus1: detached
umass1: detached
umass1: at uhub1 port 1 (addr 2) disconnected
uvm_fault(0xffffffff81904f40, 0xffffffff81d9a000, 1) -> e
fatal page fault in supervisor mode
trap type 6 code 0 rip 0xffffffff80560e28 cs 0x8 rflags 0x10202 cr2
0xffffffff81d9a000 ilevel 0 rsp 0xffff93026bac7df0
curlwp 0xffffe98b6b920480 pid 0.163 lowest kstack 0xffff93026bac32c0

bt from crash:
dev_findproduct() at dev_findproduct+0x3c
__kernel_end() at ffffffff81da0033
usbd_fill_deviceinfo() at usbd_fill_deviceinfo+0x68
usbd_add_dev_event() at usbd_add_dev_event+0x34
usb_disconnect_port() at usb_disconnect_port+0x1a3
uhub_explore() at uhub_explore+0x214
usb_discover.isra.0() at usb_discover.isra.0+0xab
usb_event_thread() at usb_event_thread+0x77

Anyone have any thoughts?