Re: Oops in 4.6-rc2: NULL pointer dereference in cdc-acm

From: Oliver Neukum
Date: Thu Apr 07 2016 - 02:59:45 EST


On Wed, 2016-04-06 at 22:48 +0200, Gabriele Mazzotta wrote:
> Hi,
>
> I'm getting a kernel oops when I plug some smartphone via USB to my
> laptop, which is currently running the v4.6-rc2.
>
> The problem seems to be caused by a81cf9799ad7 ("cdc-acm: implement
> put_char() and flush_chars()").
>
> A simple NULL pointer check prevents the crash, but since I have no
> use of cdc-acm and I didn't read the code, I don't know if some other
> changes are required.
>
> Here below you can find the change I did to prevent the crash and
> the dmesg showing the problem.

Hi,

thank you for reporting this. You are the second one to report it.
I send a fix upstream last week.
Greg, can we merge this for the next rc? People are hitting this
bug.

Regards
Oliver