| Message ID | 20210915061036.2577971-1-yhs@fb.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] selftests/bpf: skip btf_tag test if btf_tag attribute not supported | expand |
On Tue, Sep 14, 2021 at 11:10 PM Yonghong Song <yhs@fb.com> wrote: > > Commit c240ba287890 ("selftests/bpf: Add a test with a bpf > program with btf_tag attributes") added btf_tag selftest > to test BTF_KIND_TAG generation from C source code, and to > test kernel validation of generated BTF types. > But if an old clang (clang 13 or earlier) is used, the > following compiler warning may be seen: > progs/tag.c:23:20: warning: unknown attribute 'btf_tag' ignored > and the test itself is marked OK. The compiler warning is bad > and the test itself shouldn't be marked OK. > > This patch added the check for btf_tag attribute support. > If btf_tag is not supported by the clang, the attribute will > not be used in the code and the test will be marked as skipped. > For example, with clang 13: > ./test_progs -t btf_tag > #21 btf_tag:SKIP > Summary: 1/0 PASSED, 1 SKIPPED, 0 FAILED > > The selftests/README.rst is updated to clarify when the btf_tag > test may be skipped. > > Signed-off-by: Yonghong Song <yhs@fb.com> Applied. Thanks for the quick follow up.
diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst index 9b17f2867488..8200c0da2769 100644 --- a/tools/testing/selftests/bpf/README.rst +++ b/tools/testing/selftests/bpf/README.rst @@ -201,6 +201,20 @@ Without it, the error from compiling bpf selftests looks like: __ https://reviews.llvm.org/D93563 +btf_tag test and Clang version +============================== + +The btf_tag selftest require LLVM support to recognize the btf_tag attribute. +It was introduced in `Clang 14`__. + +Without it, the btf_tag selftest will be skipped and you will observe: + +.. code-block:: console + + #<test_num> btf_tag:SKIP + +__ https://reviews.llvm.org/D106614 + Clang dependencies for static linking tests =========================================== diff --git a/tools/testing/selftests/bpf/prog_tests/btf_tag.c b/tools/testing/selftests/bpf/prog_tests/btf_tag.c index f939527ede77..91821f42714d 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_tag.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_tag.c @@ -10,5 +10,11 @@ void test_btf_tag(void) skel = tag__open_and_load(); if (!ASSERT_OK_PTR(skel, "btf_tag")) return; + + if (skel->rodata->skip_tests) { + printf("%s:SKIP: btf_tag attribute not supported", __func__); + test__skip(); + } + tag__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/tag.c b/tools/testing/selftests/bpf/progs/tag.c index 17f88c58a6c5..b46b1bfac7da 100644 --- a/tools/testing/selftests/bpf/progs/tag.c +++ b/tools/testing/selftests/bpf/progs/tag.c @@ -4,8 +4,19 @@ #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> +#ifndef __has_attribute +#define __has_attribute(x) 0 +#endif + +#if __has_attribute(btf_tag) #define __tag1 __attribute__((btf_tag("tag1"))) #define __tag2 __attribute__((btf_tag("tag2"))) +volatile const bool skip_tests __tag1 __tag2 = false; +#else +#define __tag1 +#define __tag2 +volatile const bool skip_tests = true; +#endif struct key_t { int a; @@ -20,7 +31,6 @@ struct { __type(value, __u64); } hashmap1 SEC(".maps"); -__u32 total __tag1 __tag2 = 0; static __noinline int foo(int x __tag1 __tag2) __tag1 __tag2 {
Commit c240ba287890 ("selftests/bpf: Add a test with a bpf program with btf_tag attributes") added btf_tag selftest to test BTF_KIND_TAG generation from C source code, and to test kernel validation of generated BTF types. But if an old clang (clang 13 or earlier) is used, the following compiler warning may be seen: progs/tag.c:23:20: warning: unknown attribute 'btf_tag' ignored and the test itself is marked OK. The compiler warning is bad and the test itself shouldn't be marked OK. This patch added the check for btf_tag attribute support. If btf_tag is not supported by the clang, the attribute will not be used in the code and the test will be marked as skipped. For example, with clang 13: ./test_progs -t btf_tag #21 btf_tag:SKIP Summary: 1/0 PASSED, 1 SKIPPED, 0 FAILED The selftests/README.rst is updated to clarify when the btf_tag test may be skipped. Signed-off-by: Yonghong Song <yhs@fb.com> --- tools/testing/selftests/bpf/README.rst | 14 ++++++++++++++ tools/testing/selftests/bpf/prog_tests/btf_tag.c | 6 ++++++ tools/testing/selftests/bpf/progs/tag.c | 12 +++++++++++- 3 files changed, 31 insertions(+), 1 deletion(-)