[PATCH v5 0/4] Add system-wide tunables

[Michael Jeanson]

On 2026-02-12 14:39, DJ Delorie wrote:
> Michael Jeanson <mjeanson@efficios.com> writes:
>> So most tests that use GLIBC_TUNABLES should be modified to explictly
>> check that the tunables they depend on are set to the expected values?
>>
>> For example in the rseq-disabled test I could add something like this at
>> the beginning of the test:
>>
>> static void
>> check_rseq_tunable_disabled (void)
>> {
>>     bool rseq_tunable = TUNABLE_GET_FULL (glibc, pthread, rseq, int, NULL);
>>
>>     if (rseq_tunable)
>>       FAIL_UNSUPPORTED ("rseq tunable forced to enabled, skipping test");
>> }
> 
> Yes, that's what I was thinking.  It would make the tests more robust,
> although I don't expect many non-overridable system-level tunables, less
> so on libc developers' machines ;-)

If the button exists, someone will press it ;)

> 
> Ideally, tests should check *everything* that's related to the test,
> either to ensure the test is operating in the right environment to test
> what it's testing, or to check that the framework itself is operating
> correctly.  This avoids false positives.  Such rigor is rarely required,
> but your example is a case where it would be.

I agree, I'll prepare some patches for the rseq tests to send once this 
series is commited.

Thanks!

Michael