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

[Oliver Neukum <oneukum@suse.com>]

On Mon, 2016-10-17 at 17:20 +0200, Wim Osterholt wrote:
> On Mon, Oct 17, 2016 at 04:10:45PM +0200, Oliver Neukum wrote:
> > Hi,
> >    
> > I got one of those devices. However, I don't get a crash.
> > Could you please give me instructions on how you trigger it?
>   
> That's not too hard, just plug it in. :-)
>   
> However you must have set cdc_acm in your kernel, or availabe as a module. 
> It happens on all my machines on kernels 4.8 and 4.9.
> Now, all my kernel configs will differ a bit, but must have something
> peculiar in common. Or you've received a totally different device.
>  
> Here's one config at http://webserver.djo.tudelft.nl/.config-4.8.1
>  
> Many options are inherited by 'make oldconfig' from version to version,
> without me knowing what it all means. So maybe it's just a weird combination
> of options then?

Oct 18 14:05:07 linux-dtbq.site kernel: usb 1-9: new full-speed USB device number 10 using xhci_hcd
Oct 18 14:05:07 linux-dtbq.site mtp-probe[2583]: checking bus 1, device 10: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-9"
Oct 18 14:05:07 linux-dtbq.site mtp-probe[2583]: bus: 1, device: 10 was not an MTP device
Oct 18 14:05:07 linux-dtbq.site kernel: usb 1-9: New USB device found, idVendor=0572, idProduct=1340
Oct 18 14:05:07 linux-dtbq.site kernel: usb 1-9: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Oct 18 14:05:07 linux-dtbq.site kernel: usb 1-9: Product: USB Modem
Oct 18 14:05:07 linux-dtbq.site kernel: usb 1-9: Manufacturer: Conexant
Oct 18 14:05:07 linux-dtbq.site kernel: usb 1-9: SerialNumber: 12345678
Oct 18 14:05:07 linux-dtbq.site kernel: cdc_acm 1-9:1.0: ttyACM0: USB ACM device
Oct 18 14:05:07 linux-dtbq.site kernel: usbcore: registered new interface driver cdc_acm
Oct 18 14:05:07 linux-dtbq.site kernel: cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
Oct 18 14:05:11 linux-dtbq.site ModemManager[901]: <info>  Creating modem with plugin 'Generic' and '1' ports
Oct 18 14:05:11 linux-dtbq.site ModemManager[901]: <info>  Modem for device at '/sys/devices/pci0000:00/0000:00:14.0/usb1/1-9' successfully created
Oct 18 14:05:11 linux-dtbq.site ModemManager[901]: <warn>  Modem couldn't be initialized: couldn't load current capabilities: Failed to determine modem capabilities.
Oct 18 14:05:11 linux-dtbq.site NetworkManager[945]: <warn> (ttyACM0): failed to look up interface index
Oct 18 14:05:11 linux-dtbq.site NetworkManager[945]: <info> (ttyACM0): device state change: unmanaged -> unavailable (reason 'none') [10 20 0]
Oct 18 14:05:11 linux-dtbq.site NetworkManager[945]: <info> (ttyACM0): deactivating device (reason 'none') [0]                                                                                                                    
Oct 18 14:05:11 linux-dtbq.site NetworkManager[945]: <info> (ttyACM0): modem state 'unknown'                                                                                                                                      
Oct 18 14:05:11 linux-dtbq.site NetworkManager[945]: <info> (ttyACM0): new Broadband device (driver: 'cdc_acm' ifindex: 0)                                                                                                        
Oct 18 14:05:11 linux-dtbq.site NetworkManager[945]: <info> (ttyACM0): exported as /org/freedesktop/NetworkManager/Devices/3     

It definitely does not crash and is probed and your .config is not
extremely unusual.
I am afraid unless you test the last patch I sent we will not make
progress. Something odd is going on.

	Regards
		Oliver