Commit 2ba4badc authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

bpf: selftests: Update clang requirement in README.rst for testing kfunc call 



This patch updates the README.rst to specify the clang requirement
to compile the bpf selftests that call kernel function.

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210330054156.2933804-1-kafai@fb.com
parent 5bdca94f

tools/testing/selftests/bpf/README.rst

+14 −0
Original line number Diff line number Diff line
@@ -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