| Message ID | 20210330054156.2933804-1-kafai@fb.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | BPF |
| Headers | show |
| Series | bpf: Update doc about calling kernel function | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 10 maintainers not CCed: linux-kselftest@vger.kernel.org yhs@fb.com kpsingh@kernel.org andrii@kernel.org clang-built-linux@googlegroups.com nathan@kernel.org john.fastabend@gmail.com songliubraving@fb.com ndesaulniers@google.com shuah@kernel.org |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 17 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
> On Mar 29, 2021, at 10:41 PM, Martin KaFai Lau <kafai@fb.com> wrote: > > 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 <kafai@fb.com> Acked-by: Song Liu <songliubraving@fb.com>
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
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 <kafai@fb.com> --- tools/testing/selftests/bpf/README.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+)