On Tue, 2016-09-27 at 18:34 +0200, Wim Osterholt wrote:
> On Thu, Sep 22, 2016 at 04:40:50PM +0200, Oliver Neukum wrote:
> > 
> > dmesg -c
> > echo 9 > /proc/sysrq-trigger
> > modprobe cdc_acm
> > echo "module cdc_acm +mpf" > /sys/kernel/debug/dynamic_debug/control
> > 
> > [plug your device in]
> > 
> > and provide the full output of dmesg after that.
> 
> After some experimenting I succeeded in grabbing it over the serial port.
> The console was immedately frozen, but the serial port kept working:

Very good. This is a valid oops. We can do two things. When I
decode it, seems to crash in acm_alloc_minor() which does not make
sense. It is likely that our kernels or compilers are a bit different.
Could you please call gdb on your kernel module cdc-acm.ko
and do:

list *(acm_probe+0x4ee)

this should show you where it crashes. In addition I've attached
a patch with paranoid debugging. Could you compile and test a kernel
with it?

	Regards
		Oliver