Re: [PATCH] tools/perf/tests: Fix Basic BPF llvm compile to check for libbpf support

[Namhyung Kim <namhyung@kernel.org>]

Hello,

On Mon, Jul 3, 2023 at 10:03 PM Athira Rajeev
<atrajeev@linux.vnet.ibm.com> wrote:
>
> Basic BPF llvm compile fails in systems with libbpf
> that doesn't support BTF. Log shows below information.
>
>         libbpf: BTF is required, but is missing or corrupted.
>         Failed to parse test case 'Basic BPF llvm compile'
>         test child finished with -2
>         ---- end ----
>
> Here BPF llvm compile fails due to missing BTF support.
> Fix the llvm test to skip the test incase BTF support is
> missing.
>
> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
> ---
>  tools/perf/tests/llvm.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/tests/llvm.c b/tools/perf/tests/llvm.c
> index 0bc25a56cfef..4c73c9eab0bb 100644
> --- a/tools/perf/tests/llvm.c
> +++ b/tools/perf/tests/llvm.c
> @@ -4,6 +4,7 @@
>  #include <string.h>
>  #include "tests.h"
>  #include "debug.h"
> +#include <errno.h>
>
>  #ifdef HAVE_LIBBPF_SUPPORT
>  #include <bpf/libbpf.h>
> @@ -14,8 +15,12 @@ static int test__bpf_parsing(void *obj_buf, size_t obj_buf_sz)
>         struct bpf_object *obj;
>
>         obj = bpf_object__open_mem(obj_buf, obj_buf_sz, NULL);
> -       if (libbpf_get_error(obj))
> +       if (libbpf_get_error(obj)) {
> +               /* Skip if there is no BTF support */
> +               if (errno == ENOENT)

Can we use the return value of libbpf_get_error() instead of
using the errno?

Also I'm curious why it requires BTF even if the BPF program
doesn't use it.  Is there an option or something for that?

Thanks,
Namhyung


> +                       return TEST_SKIP;
>                 return TEST_FAIL;
> +       }
>         bpf_object__close(obj);
>         return TEST_OK;
>  }
> --
> 2.27.0
>