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

[poma]

On 15.11.2016 01:16, Wim Osterholt wrote:
> On Tue, Oct 18, 2016 at 02:18:43PM +0200, Oliver Neukum wrote:
> 
>> It definitely does not crash and is probed and your .config is not
>> extremely unusual.
> 
> Hmmm.
> 
>> ... Something odd is going on.
> 
> Whell, yes.
> The only thing that appears you'll have to do is unset 'CONFIG_SMP'.
> 
> My machines didn't have the luxury of multicore processors (until recently),
> so there never has been any reason to deliberately switch these options on!
> 
> In the process of searching, many options may have changed. The crash/OOPS
> has now mitigated into just a WARNING with a call trace.
> (Or it could be a totally different bug?)
> After the call trace the device is working normally and a shutdown
> completes to the end now.
> That is with the config given here:
> http://webserver.djo.tudelft.nl/.config-4.9-rc4.OK (CONFIG_SMP=y)
> http://webserver.djo.tudelft.nl/WARNING-4.9-rc4    (call trace for C_S unset)
> 
> Tests on other machines with (slightly) different configs all seem to
> confirm that the problems are gone when CONFIG_SMP is set.
> 
> Regards, Wim.
> 
> 

Try retest with mainline 4.9-rc5,
CONFIG_SMP was not crucial[1].

$ grep CONFIG_SMP /boot/config-4.9.0-0.rc5.git0.1.fc26.x86_64*
/boot/config-4.9.0-0.rc5.git0.1.fc26.x86_64:CONFIG_SMP=y
/boot/config-4.9.0-0.rc5.git0.1.fc26.x86_64+debug:CONFIG_SMP=y

[1] https://www.spinics.net/lists/linux-usb/msg148852.html