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

[Po-Hsu Lin]

[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.

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(-)

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2.7.4