Regarding the bug in FreeBSD kernel driver(s)

[Hans Petter Selasky]

On 2019-08-13 22:08, Ian Lepore wrote:
> So once a device is attached the first time, its usb ivars are wiped
> out.  That code was surely written in a time before the devctl stuff
> was added to allow disabling/enabling a device on the fly.  I'm not
> sure whether it will be easy to keep the ivar data around, but if so, I
> think that would be the right fix.
> 
> The NULL pointer checks in the patches will prevent a kernel panic, but
> don't really make devctl enable work properly.  Speaking of devctl, you
> don't need a program to test this, you can do it from the command line:
> 
>     devctl disable uhub2
>     devctl enable uhub2
>     <panic happens here>

Hi,

USB drivers are not supposed to be managed outside the USB enumeration 
thread. Using devctl on USB driver is not supported. Only usbconfig is 
allowed to attach/detach USB devices.

Should we perhaps teach devctl to not touch USB devices?

--HPS