camcontrol / devd / USB plug/unplug crashes 5.4-RELEASE

[Juho Vuori]

This is not quite predictable, but this has happened to me few times
every day for about a week now, so I think it's worth reporting. I can
also easily reproduce this in less than one minute as well, if you need
more information.

On 5.4-RELEASE: Take an USB memory, plug it into your system, wait until
information gets written on console about it, then run camcontrol
devlist, then unplug the device. Repeat for a few times and at
some point the system crashes.

I think that possibly devd is required for this to happen as well, as I
once tried to reproduce this in single user mode without success.

The crash happens in a bit different situations, but here is an
incomplete stack trace of my latest crash: (I'm writing these on piece
of paper, and I'm lazy, so please tell, if more info is necessary, and
I'll crash my system again)

fault code: supervisor read, page not present

pid 640(camcontrol) tid 100071, td 0xc1d22190

strncpy (d18da9bc, d00006, 10) at strncpy+0x14
xptedtbusfunuc
xptbustraverse
xptedtmatch
xpt_action
xptioctl
spec_ioctl
spec_vnoperate
vn_ioctl
ioctl
syscall
Xint0x80_syscall


I haven't tried other devices than USB memories, and I've only tested
this on 5.4.

Juho