Re: crash by cdc_acm driver in kernels 4.8-rc1/5

From: Wim Osterholt
Date: Thu Sep 22 2016 - 13:56:53 EST

> >Please look up the bConfigurationValue for your device
> >in sysfs.

I didn't explicitly say that this was done under kernel-4.7.4, otherwise
it may have been impossible under 4.8 .

On Thu, Sep 22, 2016 at 04:40:50PM +0200, Oliver Neukum wrote:
> OK. Strange. Please do
> 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.

You don't state if this must be done in a safe 4.7.4 or a crashable 4.8.
(if I get that far to retrieve dmesg to a file).

Anyway, echo "module cdc_acm +mpf" > /sys/kernel/debug/dynamic_debug/control
results in 'No such file or directory' because there is no 'dynamic_debug'.

The kernel option DYNAMIC_DEBUG was not set.
A new kernel is compiling now..

Groeten, Wim.