Re: USB locks up system -- WAS Re: shutdown or acpi problem

On Sun, Nov 16, 2014 at 06:34:42PM +0000, Mark R V Murray wrote:
> 
> > On 16 Nov 2014, at 18:31, Ian Lepore <ian_at_FreeBSD.org> wrote:
> > 
> > The point I'm trying to make here is that you trimmed away the important
> > part of the prior messages and replied only to the part where Steve's
> > debugging efforts were somewhat speculating.  The non-speculative part
> > was where he bisected the failure to an exact commit:
> > 
> >>>> The problem is caused
> >>>> by r273872.  This is the recent random device patch.  I have no
> >>>> idea why removing a usb device would cause the system to lock
> >>>> up other than random is probably trying to harvest some entropy.
> 
> I?m sorry my commit caused the problem.
> 

Nothing to be sorry about.  This is -current afterall.

> I?m also trying to find out why, but I don?t know enough about USB or
> mass-storage devices to know why, so this may take me a while. In the
> meanwhile, I?ll try to help by pointing out things I do know.

Yes, I did the bisection to find that r273872 exposes the problem.
What I don't know is if this is hardware specific to a Dell Latitude
D530 laptop, USB specific, or some weird interaction between the
random and USB.

What I also find odd is that I seem to be the only person seeing
this behavior when it is trivial for me to reproduce: boot laptop,
plug in usb device, wait usb recognizes the device, then unplug 
the device.

If you have not read the entire thread, once the laptop keyboard and
video output lock up, I can ssh into the laptop.  If I run usbconfig,
it hangs, ^T tells me it is stuck in SX Lock, and the /dev/da0* devices
have not been destroyed. 

-- 
Steve