Re: [PATCH bpf-next 2/3] selftests/bpf: report placeholder tests as SKIP, not OK

> diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h
> index 5eacf1b43252..88b0bfba83bb 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_misc.h
> +++ b/tools/testing/selftests/bpf/progs/bpf_misc.h
> @@ -106,6 +106,11 @@
>   * __description     Text to be used for display and as an additional filter
>   *                   alias, while the original program name stays matchable.
>   *
> + * __skip            Report the test as SKIP with the given reason instead of
> + *                   running it. For placeholder programs that stand in for a
> + *                   feature the toolchain or JIT cannot provide, so a run does
> + *                   not report OK for coverage it never executed.
> + *
>   * __log_level       Log level to use for the program, numeric value expected.
>   *
>   * __flag            Adds one flag use for the program, the following values are valid:
> @@ -139,6 +144,7 @@
>  #define __failure		__test_tag("test_expect_failure")
>  #define __success		__test_tag("test_expect_success")
>  #define __description(desc)	__test_tag("test_description=" desc)
> +#define __skip(reason)		__test_tag("test_skip=" reason)
>  #define __msg_unpriv(msg)	__test_tag("test_expect_msg_unpriv=" msg)

[ ... ]

> diff --git a/tools/testing/selftests/bpf/progs/verifier_ldsx.c b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
> index 41340877dc9d..e58ea69e3854 100644
> --- a/tools/testing/selftests/bpf/progs/verifier_ldsx.c
> +++ b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
> @@ -436,6 +436,7 @@ void kfunc_root(void)
>
>  SEC("socket")
>  __description("cpuv4 is not supported by compiler or jit, use a dummy test")
> +__skip("cpuv4 is not supported by compiler or jit")
>  __success
>  int dummy_test(void)
>  {

[ ... ]

> diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c
> index 07807757b518..794a7dfb0579 100644
> --- a/tools/testing/selftests/bpf/test_loader.c
> +++ b/tools/testing/selftests/bpf/test_loader.c
> @@ -70,6 +70,7 @@ struct test_spec {
>  	int arch_mask;
>  	int load_mask;
>  	int linear_sz;
> +	const char *skip_reason;
>  	bool auxiliary;
>  	bool valid;
>  };
> @@ -456,6 +457,8 @@ static int parse_test_spec(struct test_loader *tester,
>  			continue;
>  		if ((val = str_has_pfx(s, "test_description="))) {
>  			description = val;
> +		} else if ((val = str_has_pfx(s, "test_skip="))) {
> +			spec->skip_reason = val;
>  		} else if (strcmp(s, "test_expect_failure") == 0) {
>  			spec->priv.expect_failure = true;
>  			spec->mode_mask |= PRIV;
> @@ -1327,6 +1330,12 @@ void run_subtest(struct test_loader *tester,
>  	if (!test__start_subtest_with_desc(subspec->name, subspec->description))
>  		return;
>
> +	if (spec->skip_reason) {
> +		printf("%s:SKIP: %s\n", __func__, spec->skip_reason);
> +		test__skip();
> +		return;
> +	}
> +
>  	if ((get_current_arch() & spec->arch_mask) == 0) {
>  		test__skip();
>  		return;

The commit converts 13 placeholder programs to use the new __skip()
annotation, but two feature-gated placeholders with the identical
pattern were not converted. Were these intentionally excluded?

The preceding commit b1831d82fe2c states "Eleven of the thirteen
feature-gated placeholder programs are called dummy_test", but grep
finds fifteen such programs.

tools/testing/selftests/bpf/progs/verifier_aggregate_ret.c has a
compile-time gate at line 8:

  #if defined(__clang_major__) && __clang_major__ >= 23

with its #else arm at lines 166-172 supplying the same __success
placeholder pattern that this commit converts everywhere else:

  #else

  SEC("socket")
  __description("verifier_aggregate_ret: needs LLVM 23, dummy test")
  __success
  int dummy_test(void)

Similarly, tools/testing/selftests/bpf/progs/verifier_percpu_addr.c has
a gate at line 7:

  #if defined(__TARGET_ARCH_x86)

with its #else placeholder at lines 60-66:

  #else

  SEC("raw_tp")
  __description("percpu addr dummy")
  __success
  int dummy_test(void)

Both reach the modified test_loader.c code path via
prog_tests/verifier.c (test_verifier_aggregate_ret and
test_verifier_percpu_addr), so __skip() would work for them.

The gates fire today, so the placeholders are what actually gets built
and reported:
- verifier_aggregate_ret.c: any toolchain older than clang 23
- verifier_percpu_addr.c: every non-x86 build (arm64, s390x, riscv64,
  loongarch)

On those builds these two tests still report OK for coverage that never
executed.


---
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CI run summary: https://github.com/kernel-patches/bpf/actions/runs/32523960074