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

[Wim Osterholt]

On Tue, Oct 18, 2016 at 02:18:43PM +0200, Oliver Neukum wrote:
> 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. :-)

> It definitely does not crash and is probed and your .config is not
> extremely unusual.

Hmmm.

> ... Something odd is going on.

You didn't try it on many machines, did you?
The latest install on a 'new' laptop (Dell latitude D610) did also crash.
For if it matters, they all have Intel chipset here.
Crashes now on five machines.

An worn-out Dell laptop (Inspiron 510m) suddenly got stuck in a reboot loop
for 4.7.10 and 4.9-rc3, but a 4.8-rc4 kept running. Even more miraculously,
it didn't crash on inserting the modem.
I could even compile a 4.9-rc3 that didn't crash on that machine.
The effect was even portable!

I now have a crashing and a non-crashing 4.9-rc3 kernel.
You can find the configs here:
http://webserver.djo.tudelft.nl/.config-4.9-rc3.notOK
http://webserver.djo.tudelft.nl/.config-4.9-rc3.OK

They are very different, so it will take a lot of time to eliminate the
options one by one.
So if you have an idea of which options, or combination of options are evil,
I'd like to hear.


Regards, Wim.