On Thu, Jun 20, 2019 at 10:17:04PM -0700, Andrii Nakryiko wrote:

On Thu, Jun 20, 2019 at 1:08 AM Naresh Kamboju naresh.kamboju@linaro.org wrote:

...

selftests: bpf test_libbpf.sh failed running Linux -next kernel 20190618 and 20190619.

Here is the log from x86_64, # selftests bpf test_libbpf.sh bpf: test_libbpf.sh_ # # [0] libbpf BTF is required, but is missing or corrupted.

You need at least clang-9.0.0 (not yet released) to run some of these tests successfully, as they rely on Clang's support for BTF_KIND_VAR/BTF_KIND_DATASEC.

Can there be a runtime check for BTF that emits a skip instead of a fail in such a case?

Thanks, Dan

...

libbpf: BTF_is # # test_libbpf failed at file test_l4lb.o failed: at_file # # selftests test_libbpf [FAILED] test_libbpf: [FAILED]_ # [FAIL] 29 selftests bpf test_libbpf.sh selftests: bpf_test_libbpf.sh [FAIL]

Full test log, https://qa-reports.linaro.org/lkft/linux-next-oe/build/next-20190619/testrun...

Test results comparison, https://qa-reports.linaro.org/lkft/linux-next-oe/tests/kselftest/bpf_test_li...

Good linux -next tag: next-20190617 Bad linux -next tag: next-20190618 git branch master git commit 1c6b40509daf5190b1fd2c758649f7df1da4827b git repo https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

Best regards Naresh Kamboju

On Mon, Jun 24, 2019 at 11:32:25AM -0700, Andrii Nakryiko wrote:

On Fri, Jun 21, 2019 at 9:17 AM Dan Rue dan.rue@linaro.org wrote:

...

On Thu, Jun 20, 2019 at 10:17:04PM -0700, Andrii Nakryiko wrote:

...

On Thu, Jun 20, 2019 at 1:08 AM Naresh Kamboju naresh.kamboju@linaro.org wrote:

...

selftests: bpf test_libbpf.sh failed running Linux -next kernel 20190618 and 20190619.

Here is the log from x86_64, # selftests bpf test_libbpf.sh bpf: test_libbpf.sh_ # # [0] libbpf BTF is required, but is missing or corrupted.

You need at least clang-9.0.0 (not yet released) to run some of these tests successfully, as they rely on Clang's support for BTF_KIND_VAR/BTF_KIND_DATASEC.

Can there be a runtime check for BTF that emits a skip instead of a fail in such a case?

I'm not sure how to do this simply and minimally intrusively. The best I can come up with is setting some envvar from Makefile and checking for that in each inidividual test, which honestly sounds a bit gross.

How hard is it for you guys to upgrade compiler used to run these test?

We should be able to run kselftest with any compiler that Linux supports, so that we can test with the toolchain that users actually run with.

I would say if it's not possible to check at runtime, and it requires clang 9.0, that this test should not be enabled by default.

Maybe something could be done in Makefile for that? Only add it to TEST_GEN_PROGS if the toolchain feature exists, otherwise add it to TEST_GEN_PROGS_EXTENDED. I don't know if this is a good idea.. but from kselftest.rst:

TEST_PROGS, TEST_GEN_PROGS mean it is the executable tested by default. ... TEST_PROGS_EXTENDED, TEST_GEN_PROGS_EXTENDED mean it is the executable which is not tested by default.

Dan

...

Thanks, Dan

...

...

libbpf: BTF_is # # test_libbpf failed at file test_l4lb.o failed: at_file # # selftests test_libbpf [FAILED] test_libbpf: [FAILED]_ # [FAIL] 29 selftests bpf test_libbpf.sh selftests: bpf_test_libbpf.sh [FAIL]

Full test log, https://qa-reports.linaro.org/lkft/linux-next-oe/build/next-20190619/testrun...

Test results comparison, https://qa-reports.linaro.org/lkft/linux-next-oe/tests/kselftest/bpf_test_li...

Good linux -next tag: next-20190617 Bad linux -next tag: next-20190618 git branch master git commit 1c6b40509daf5190b1fd2c758649f7df1da4827b git repo https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

Best regards Naresh Kamboju

-- Linaro - Kernel Validation

On Mon, Jun 24, 2019 at 12:58:15PM -0700, Alexei Starovoitov wrote:

On Mon, Jun 24, 2019 at 12:53 PM Dan Rue dan.rue@linaro.org wrote:

...

I would say if it's not possible to check at runtime, and it requires clang 9.0, that this test should not be enabled by default.

The latest clang is the requirement. If environment has old clang or no clang at all these tests will be failing.

Hi Alexei!

I'm not certain if I'm interpreting you as you intended, but it sounds like you're telling me that if the test build environment does not use 'latest clang' (i guess latest as of today?), that these tests will fail, and that is how it is going to be. If I have that wrong, please correct me and disregard the rest of my message.

Please understand where we are coming from. We (and many others) run thousands of tests from a lot of test frameworks, and so our environment often has mutually exclusive requirements when it comes to things like toolchain selection.

We believe, strongly, that a test should not emit a "fail" for a missing requirement. Fail is a serious thing, and should be reserved for an actual issue that needs to be investigated, reported, and fixed.

This is how we treat test failures - we investigate, report, and fix them when possible. When they're not real failures, we waste our time (and yours, in this case).

By adding the tests to TEST_GEN_PROGS, you're adding them to the general test set that those of us running test farms try to run continuously across a wide range of hardware environments and kernel branches.

My suggestion is that if you do not want us running them, don't add them to TEST_GEN_PROGS. I thought the suggestion of testing for adequate clang support and adding them conditionally at build-time was an idea worth consideration.

Thanks, Dan