Re: [PATCH v2] kasan: Support for r/w instrumentation control

[Dmitry Vyukov]

On Tue, Dec 13, 2016 at 10:20 AM, Andrey Ryabinin
<aryabinin@xxxxxxxxxxxxx> wrote:
>
>
> On 12/13/2016 11:58 AM, Dmitry Vyukov wrote:
>
>> --- a/Documentation/dev-tools/kasan.rst
>> +++ b/Documentation/dev-tools/kasan.rst
>> @@ -40,6 +40,14 @@ similar to the following to the respective kernel Makefile:
>>
>>      KASAN_SANITIZE := n
>>
>> +Sometimes it may be useful to disable instrumentation of reads, or writes
>> +or both for the entire kernel. For example, if binary size is a concern,
>> +it may be useful to disable instrumentation of reads to reduce binary size but
>> +still catch more harmful bugs on writes. Or, if one is interested only in
>> +sanitization of a particular module and performance is a concern, she can
>> +disable instrumentation of both reads and writes for kernel code.
>> +Instrumentation can be disabled with CONFIG_KASAN_READS and
>> CONFIG_KASAN_WRITES.
>> +
>
> I don't understand this. How this can be related to modules? Configs are global.
> You can't just disable/enable config per module.


Build everything without instrumentation. Then enable instrumentation
and do "make lib/test_kasan.ko".
Or build everything, copy out bzImage, change config, build everything again.