Re: [PATCHSET 0/5] User mapped provided buffer rings

Jens Axboe
2023-03-17T16:37:12Z

On 3/17/23 10:15?AM, John David Anglin wrote:
> On 2023-03-17 11:57 a.m., Jens Axboe wrote:
>>> Running test buf-ring.t register buf ring failed -22
>>> test_full_page_reg failed
>>> Test buf-ring.t failed with ret 1
>> The buf-ring failure with the patch from my previous message is because
>> it manually tries to set up a ring with an address that won't work. The
>> test case itself never uses the ring, it's just a basic
>> register/unregister test. So would just need updating if that patch goes
>> in to pass on hppa, there's nothing inherently wrong here.
>>
> I would suggest it. From page F-7 of the PA-RISC 2.0 Architecture:
>
> All other uses of non-equivalent aliasing (including simultaneously
> enabling multiple non-equivalently aliased translations where one
> or more allow for write access) are prohibited, and can cause
> machine checks or silent data corruption, including data corruption
> of unrelated memory on unrelated pages.

I did add a patch to skip that sub-test on hppa, as there's just no way
to make that one work as it relies on manually aligning memory to
trigger an issue in an older kernel. So the test should pass now in the
liburing master branch.

I'll send out the alignment check patch and we can queue that up for
6.4.

--
Jens Axboe