Hi Jarkko,
On 8/17/2022 7:53 AM, Jarkko Sakkinen wrote:
> On Wed, Aug 17, 2022 at 05:44:31PM +0300, Jarkko Sakkinen wrote:
>> On Tue, Aug 16, 2022 at 09:35:27PM -0700, Reinette Chatre wrote:
>>>>>> This portion below was also copied from previous test and by only
>>>>>> testing a write to the first page of the range the purpose is not
>>>>>> clear. Could you please elaborate if the intention is to only test
>>>>>> accessibility of the first page and why that is sufficient?
>>>>>
>>>>> It is sufficient because the test reproduces the bug. It would have to be
>>>>> rather elaborated why you would possibly want to do more than that.
>>>
>>> That is fair. An accurate comment (currently an inaccurate copy&paste) would
>>> help to explain this part of the test.
>>
>> I would simply add something like:
>>
>> /*
>> * Define memory pool size big enough to trigger the reclaimer in the EAUG
>> * path of the page reclaimer.
>> */
>>
>> Suggestions/edits obviously welcome for the comment.
The comment seems to better match the code below than the area referred to above:
static const unsigned long edmm_size = 8589934592; //8G
Even so, I think that raises the point that this is platform specific since
edmm_size of 8GB would not trigger reclaimer on all platforms.
How about adjusting it to:
/*
* Define memory pool size big enough to trigger the reclaimer in the EAUG
* path of the page reclaimer on some platforms. This constant has been
* successful in triggering a bug on some platforms (independent of the
* platforms where the reclaimer is triggered) and thus considered
* appropriate for general use.
*/
Regarding the area referred to above, a comment like below may help:
/*
* Pool of pages were successfully added to enclave. Perform sanity
* check on first page of the pool only to ensure data can be written
* to and read from a dynamically added enclave page.
*/
>
> I wonder if we could put .bt files somewhere to make them available. In
> root causing this bug bpftrace scripting was the key so it would nice to
> have them available along with kselftest.
>
> I could imagine that we end up also in future to bugs allocation so
> it would have the script when you clone the kernel tree, and possibly
> more scripts in future.
>
> E.g. add bt/alloc-error.bt under tools/testing/selftests/sgx.
Thank you very much for helping to debug this issue. I also think
the scripts you created are very valuable and making them easily
accessible sounds great.
Reinette
