Re: [PATCH bpf-next v3 8/8] selftests/bpf: skip the struct_ops arena tests without compiler support

[Vineet Gupta <vineet.gupta@linux.dev>]

On 11/2/26 2:39 PM, Alexei Starovoitov wrote:
> On Mon, Nov 02, 2026 at 02:07 PM Vineet Gupta <vineet.gupta@linux.dev> wrote:
>> These are not driven by test_loader, so __skip_without_arena does not
>> reach them.  Use the flag-in-.data pattern linked_externs.c already
>> uses for the same situation: the program exports skip_tests, and the
>> host checks it before attaching and reports SKIP.
> cast_kern() is cleaner...
> It's a nop when the compiler supports arena.

Nice, definitely better than what I had since now more code is exercised 
than being skipped.

Thx,
-Vineet

> diff --git a/tools/testing/selftests/bpf/progs/struct_ops_arena.c b/tools/testing/selftests/bpf/progs/struct_ops_arena.c
> index 8aa8639..3fffa24 100644
> --- a/tools/testing/selftests/bpf/progs/struct_ops_arena.c
> +++ b/tools/testing/selftests/bpf/progs/struct_ops_arena.c
> @@ -86,7 +86,6 @@ struct bpf_testmod_ops3 testmod_arena = {
>   SEC("syscall")
>   int trigger(void *ctx)
>   {
> -#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
>   	u64 __arena *val;
>   	int ret;
>
> @@ -94,6 +93,7 @@ int trigger(void *ctx)
>   	if (!val)
>   		return 1;
>
> +	cast_kern(val);
>   	*val = 41;
>   	ret = bpf_testmod_ops3_call_test_arena((u64 *)val);
>   	if (ret)
> @@ -134,6 +134,5 @@ int trigger(void *ctx)
>   		return 11;
>
>   	bpf_arena_free_pages(&arena, (void __arena *)val, 1);
> -#endif
>   	return 0;
>   }
> diff --git a/tools/testing/selftests/bpf/progs/struct_ops_arena_autobind.c b/tools/testing/selftests/bpf/progs/struct_ops_arena_autobind.c
> index 495faa0..3455ca9 100644
> --- a/tools/testing/selftests/bpf/progs/struct_ops_arena_autobind.c
> +++ b/tools/testing/selftests/bpf/progs/struct_ops_arena_autobind.c
> @@ -45,13 +45,13 @@ int unrelated(void *ctx)
>   SEC("syscall")
>   int trigger(void *ctx)
>   {
> -#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
>   	u64 __arena *val;
>
>   	val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
>   	if (!val)
>   		return 1;
>
> +	cast_kern(val);
>   	*val = 41;
>   	if (bpf_testmod_ops3_call_test_arena((u64 *)val))
>   		return 2;
> @@ -59,6 +59,5 @@ int trigger(void *ctx)
>   		return 3;
>
>   	bpf_arena_free_pages(&arena, (void __arena *)val, 1);
> -#endif
>   	return 0;
>   }
> diff --git a/tools/testing/selftests/bpf/progs/struct_ops_arena_member.c b/tools/testing/selftests/bpf/progs/struct_ops_arena_member.c
> index a2218cd..afbe59f 100644
> --- a/tools/testing/selftests/bpf/progs/struct_ops_arena_member.c
> +++ b/tools/testing/selftests/bpf/progs/struct_ops_arena_member.c
> @@ -80,7 +80,6 @@ struct bpf_testmod_ops3 testmod_arena_member = {
>   SEC("syscall")
>   int trigger(void *ctx)
>   {
> -#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
>   	u64 __arena *val;
>   	int ret;
>
> @@ -88,6 +87,7 @@ int trigger(void *ctx)
>   	if (!val)
>   		return 1;
>
> +	cast_kern(val);
>   	*val = 41;
>   	ret = bpf_testmod_ops3_call_test_arena_member((u64 *)val);
>   	if (ret)
> @@ -104,6 +104,5 @@ int trigger(void *ctx)
>   		return 4;
>
>   	bpf_arena_free_pages(&arena, (void __arena *)val, 1);
> -#endif
>   	return 0;
>   }
> diff --git a/tools/testing/selftests/bpf/progs/struct_ops_arena_member_render.c b/tools/testing/selftests/bpf/progs/struct_ops_arena_member_render.c
> index 09b4c74..c4e134e 100644
> --- a/tools/testing/selftests/bpf/progs/struct_ops_arena_member_render.c
> +++ b/tools/testing/selftests/bpf/progs/struct_ops_arena_member_render.c
> @@ -63,7 +63,6 @@ struct bpf_testmod_ops3 testmod_arena_member_render = {
>   SEC("syscall")
>   int trigger(void *ctx)
>   {
> -#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
>   	u64 __arena *val;
>   	int ret;
>
> @@ -71,6 +70,7 @@ int trigger(void *ctx)
>   	if (!val)
>   		return 1;
>
> +	cast_kern(val);
>   	*val = 41;
>   	ret = bpf_testmod_ops3_call_test_arena_member((u64 *)val);
>   	if (ret)
> @@ -80,6 +80,5 @@ int trigger(void *ctx)
>   		return 3;
>
>   	bpf_arena_free_pages(&arena, (void __arena *)val, 1);
> -#endif
>   	return 0;
>   }