Re: Announcement: GCC BPF is now being tested on BPF CI

[Cupertino Miranda <cupertino.miranda@oracle.com>]

I remind that just as bad as the decl_tags it also misses a solution to 
the attribute ((preserve_access_index)).
Something like #pragma clang push/pop is not viable in GCC.

Jose proposed the patch in:
  
https://lore.kernel.org/bpf/20240503111836.25275-1-jose.marchesi@oracle.com/

Maybe you could accept his patch in the meanwhile, and work on the 
intended improvements later. It would be passing more tests then roughly 
half.

Thanks

> 
> Thank you for getting this up and running!
> 
>> Hi everyone.
>>
>> GCC BPF support in BPF CI has been landed.
>>
>> The BPF CI dashboard is here:
>> https://github.com/kernel-patches/bpf/actions/workflows/test.yml
>>
>> A summary of what happens on CI (relevant to GCC BPF):
>>    * Linux Kernel is built on a target source revision
>>    * Latest snapshots of GCC 15 and binutils are downloaded
>>      * GCC BPF compiler is built and cached
>>    * selftests/bpf test runners are built with BPF_GCC variable set
>>      * BPF_GCC triggers a build of test_progs-bpf_gcc runner
>>      * The runner contains BPF binaries produced by GCC BPF
>>    * In a separate job, test_progs-bpf_gcc is executed within qemu
>>      against the target kernel
>>
>> GCC BPF is only tested on x86_64.
>>
>> On x86_64 we test the following toolchains for building the kernel and
>> test runners: gcc-13 (ubuntu 24 default), clang-17, clang-18.
>>
>> An example of successful test run (you have to login to github to see
>> the logs):
>> https://github.com/kernel-patches/bpf/actions/runs/12816136141/job/35736973856
>>
>> Currently 2513 of 4340 tests pass for GCC BPF, so a bit more than a half.
>>
>> Effective BPF selftests denylist for GCC BPF is located here:
>> https://github.com/kernel-patches/vmtest/blob/master/ci/vmtest/configs/DENYLIST.test_progs-bpf_gcc
>>
>> When a patch is submitted to BPF, normally a corresponding PR for
>> kernel-patches/bpf github repo is automatically created to trigger a
>> BPF CI run for this change. PRs opened manually will do that too, and
>> this can be used to test patches before submission.
>>
>> Since the CI automatically pulls latest GCC snapshot, a change in GCC
>> can potentially cause CI failures unrelated to Linux changes being
>> tested. This is not the only dependency like that, of course.
>>
>> In such situations, a change is usually made in CI code to mitigate
>> the failure in order to unblock the pipeline for patches. If that
>> happens with GCC, someone (most likely me) will have to reach out to
>> GCC team. I guess gcc@gcc.gnu.org would be the default point of
>> contact, but if there are specific people who should be notified
>> please let me know.