ACK+Cmnt: [B][SRU][PATCH 0/2] Skip unprivileged tests in test_verifier from bpf selftests

[Thadeu Lima de Souza Cascardo]

On Tue, Jul 05, 2022 at 04:28:15PM +0800, Po-Hsu Lin wrote:
> [Impact]
> We have kernel.unprivileged_bpf_disabled enabled for Bionic kernel:
> $ sysctl kernel.unprivileged_bpf_disabled
> kernel.unprivileged_bpf_disabled = 2
> 
> This causes all unprivileged tests in test_verifier of bpf selftests
> to fail like:
>   #0/u add+sub+mul FAIL
>   Failed to load prog 'Operation not permitted'!
> 
> Because it permanently disables unprivileged BPF access for
> the currently running kernel.
> 
> [Fix]
> * d0a0e4956f ("selftests/bpf: Count tests skipped by unpriv")
> * 0a67487403 ("selftests/bpf: Only run tests if !bpf_disabled")
> 
> These two patches can be cherry-picked into our Bionic kernel.
> 
> Note that there is a follow-up fix for 0a67487403, which is commit
> deea81228b ("selftests/bpf: check return value of fopen in
> test_verifier.c"), but this is intended for older kernels (< 4.4) thus
> I will leave it alone.
> 
> [Test]
> Patch tested with Bionic 4.15.0-188, and these unprivileged won't fail
> with "Failed to load prog 'Operation not permitted'!" anymore, they
> will be marked as skipped tests.
> 
> Overall test result improves from:
>   Summary: 551 PASSED, 286 FAILED
> To:
>   Summary: 551 PASSED, 278 SKIPPED, 8 FAILED
> 
> [Where problems could occur]
> Change limited to the bpf selftest code, no actual changes to kernel
> function. If this fix is wrong, we might get incorrect test results.
> 

Perhaps we should consider enabling unprivileged eBPF before running the test?

Cascardo.

> Joe Stringer (2):
>   selftests/bpf: Count tests skipped by unpriv
>   selftests/bpf: Only run tests if !bpf_disabled
> 
>  tools/testing/selftests/bpf/test_verifier.c | 36 +++++++++++++++++++++++++----
>  1 file changed, 32 insertions(+), 4 deletions(-)
> 
> -- 
> 2.7.4