On 22/07/2025 15:22, Arnaldo Carvalho de Melo wrote:
> If pahole is asked to encode BTF for a file with no DWARF info, don't
> fail, just skip it.
>
> This is the case, for instance, in this file in a kernel build with
> DWARF info generation enabled:
>
> $ pahole ../build/v6.15.0-rc4+/arch/x86/purgatory/purgatory.o
> libbpf: failed to find '.BTF' ELF section in ../build/v6.15.0-rc4+/arch/x86/purgatory/purgatory.o
> pahole: file '../build/v6.15.0-rc4+/arch/x86/purgatory/purgatory.o' has no supported type information.
> $
>
> Before it was failing when encoding BTF for it, now:
>
> $ pahole --btf_encode ../build/v6.15.0-rc4+/arch/x86/purgatory/purgatory.o
> $ echo $?
> 0
> $
>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Only potential issue I can see is that in the usual case of encoding BTF
from DWARF in the kernel we'd probably like to fall over if we can't
encode BTF due to DWARF absence. However current Kconfig dependencies of
CONFIG_DEBUG_INFO_BTF mean this can't happen in practice I think so
Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> ---
> pahole.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/pahole.c b/pahole.c
> index 333e71ab65924d2c..a001ec86ef1b0908 100644
> --- a/pahole.c
> +++ b/pahole.c
> @@ -3659,6 +3659,13 @@ try_sole_arg_as_class_names:
> remaining = argc;
> goto try_sole_arg_as_class_names;
> }
> +
> + if (btf_encode || ctf_encode) {
> + // If encoding is asked for and there is no DEBUG info to encode from,
> + // there are no errors, continue...
> + goto out_ok;
> + }
> +
> if (argv[remaining] != NULL) {
> cus__fprintf_load_files_err(cus, "pahole", argv + remaining, err, stderr);
> } else {
