udev + usb2 kernel race?

[Harald Hoyer]

Sitsofe Wheeler wrote:
> Hi,
> 
> We have a computer acting as a server that locks hard (PS2 keyboard
> stops responding, prompt never returns, boot gets no further) when USB2
> is enabled on FC3 (there were no lockups with FC1). I finally traced
> this down to being some sort of interaction between udev and USB2. The
> following steps reproduce the problem:
> 
> Boot the kernel with init=/bin/sh
> mount -n -t proc /proc /proc
> mount -n -t sysfs /sys /sys
> /sbin/start_udev
> /sbin/modprobe uhci-hcd
> 
> The machine will hang and not get any further nor will it respond to a
> ctrl-alt-del or sysrq commands.
> 
> modprobing uhci-hcd before starting udev causes the problem to disappear
> as does disabling USB2 (but leaving USB1 on) in the BIOS. Kernels tested
> are kernel-2.6.9-1.667 and kernel-2.6.10-1.766_FC3. lspci prints the
> following USB controller:
> 00:07.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1
> Controller (rev 16)
> 
> Does this sound like a known issue?
> 

not to me and the solution is strange... could you add a

set -x

after the first line of start_udev and look, where it hangs?