Re: [PATCH 25/26] isdn: eicon: mark divascapi incompatible with kasan

Arnd Bergmann
2017-03-03T15:37:21Z

On Fri, Mar 3, 2017 at 4:22 PM, Andrey Ryabinin <aryabinin@virtuozzo.com> wrote:
> On 03/03/2017 05:54 PM, Arnd Bergmann wrote:
>> On Fri, Mar 3, 2017 at 3:20 PM, Andrey Ryabinin <aryabinin@virtuozzo.com> wrote:
>>> On 03/02/2017 07:38 PM, Arnd Bergmann wrote:
>>>
>>> This is kinda radical solution.
>>> Wouldn't be better to just increase -Wframe-larger-than for this driver through Makefile?
>>
>> I thought about it too, and decided for disabling the driver entirely
>> since I suspected that
>> not only the per-function stack frame is overly large here but also
>> depth of the call chain,
>> which would then lead us to hiding an actual stack overflow.
>>
>
> No one complained so far ;)
> Disabling the driver like you did will throw it out from allmodconfig so it will receive less compile-testing.

Good point, I'll add a driver specific flag then and leave it there.

>> Note that this driver is almost certainly broken, it hasn't seen any
>> updates other than
>> style and compile-warning fixes in 10 years and doesn't support any of
>> the hardware
>> introduced since 2002 (the company still makes PCIe ISDN adapters, but
>> the driver
>> only supports legacy PCI versions and older buses).
>
> Which means that it's unlikely that someone will run this driver with KASAN
and trigger stack overflow (if it's really possible).

True.

Arnd