Re: [PATCH] io_uring/register: use correct location for io_rings_layout

[Pavel Begunkov <asml.silence@gmail.com>]

On 11/19/25 20:22, Jens Axboe wrote:
> On 11/19/25 10:18 AM, Pavel Begunkov wrote:
>> On 11/19/25 02:36, Jens Axboe wrote:
>>> A previous consolidated the ring size etc calculations into
>>> io_prepare_config(), but missed updating io_register_resize_rings()
>>> correctly to use the calculated values. As a result, it ended up using
>>> on-stack uninitialized values, and hence either failed validating the
>>> size correctly, or just failed resizing because the sizes were random.
>>>
>>> This caused failures in the liburing regression tests:
>>
>> That made me wonder how it could possibly pass tests for me. I even
>> made sure it was reaching the final return. Turns out the layout was
>> 0 initialised, region creation fails with -EINVAL, and then the
>> resizing test just silently skips sub-cases. It'd be great to have
>> a "not supported, skip" message.
> 
> Looks like the test runs into -EINVAL, then tries the DEFER case,
> and then doesn't check for SKIP for that. And then it returns
> success. I've added a commit for that now, so it'll return 77/SKIP
> if it does skip.
> 
> I try to avoid having tests be verbose, unless they fail. Otherwise
> it's easy to lose information you actually want in the noise. But
> it certainly should return T_EXIT_SKIP, when it skips!

Printing when tests are skipped was pretty useful because I
expect a latest kernel (+configured for testing setup) to be
to run all tests, and I'd find "test skipped" suspicious by
default. Certainly a test infra problem, but at least it
worked.

At some point it might be great to distinguish when it skips
because of unsupported io_uring features from when some
resources are not available.

On the topic, I've found this in the runner:

elif [ "${#SKIPPED[*]}" -ne 0 ] && [ -n "$TEST_GNU_EXITCODE" ]; then
	exit 77
else
	echo "All tests passed"
	exit 0
fi

But not sure who would even define TEST_GNU_EXITCODE. It should
be more helpful to always print skipped tests:

else
	echo "Tests: skipped $SKIPPED"
	echo "All tests passed"
	exit 0
fi

-- 
Pavel Begunkov