[PATCH bpf-next 2/2] bpf: selftests: Update clang requirement in README.rst for testing kfunc call
From: Martin KaFai Lau <hidden>
Date: 2021-03-30 05:43:08
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds
This patch updates the README.rst to specify the clang requirement to compile the bpf selftests that call kernel function. Signed-off-by: Martin KaFai Lau <redacted> --- tools/testing/selftests/bpf/README.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
index 3464161c8eea..65fe318d1e71 100644
--- a/tools/testing/selftests/bpf/README.rst
+++ b/tools/testing/selftests/bpf/README.rst@@ -179,3 +179,17 @@ types, which was introduced in `Clang 13`__. The older Clang versions will either crash when compiling these tests, or generate an incorrect BTF. __ https://reviews.llvm.org/D83289 + +Kernel function call test and Clang version +=========================================== + +Some selftests (e.g. kfunc_call and bpf_tcp_ca) require a LLVM support +to generate extern function in BTF. It was introduced in `Clang 13`__. + +Without it, the error from compiling bpf selftests looks like: + +.. code-block:: console + + libbpf: failed to find BTF for extern 'tcp_slow_start' [25] section: -2 + +__ https://reviews.llvm.org/D93563
--
2.30.2