Re: [PATCH V2] tools/perf/builtin-lock: Fix return code for functions in __cmd_contention

[Namhyung Kim <namhyung@kernel.org>]

On Fri, Jan 10, 2025 at 03:07:30PM +0530, Athira Rajeev wrote:
> perf lock contention returns zero exit value even if the lock contention
> BPF setup failed.
> 
>   # ./perf lock con -b true
>   libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled?
>   libbpf: failed to find '.BTF' ELF section in /lib/modules/6.13.0-rc3+/build/vmlinux
>   libbpf: failed to find valid kernel BTF
>   libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled?
>   libbpf: failed to find '.BTF' ELF section in /lib/modules/6.13.0-rc3+/build/vmlinux
>   libbpf: failed to find valid kernel BTF
>   libbpf: Error loading vmlinux BTF: -ESRCH
>   libbpf: failed to load object 'lock_contention_bpf'
>   libbpf: failed to load BPF skeleton 'lock_contention_bpf': -ESRCH
>   Failed to load lock-contention BPF skeleton
>   lock contention BPF setup failed
>   # echo $?
>    0
> 
> Fix this by saving the return code for lock_contention_prepare
> so that command exits with proper return code. Similarly set the
> return code properly for two other functions in builtin-lock, namely
> setup_output_field() and select_key().
> 
> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>

Reviewed-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung

> ---
> Changelog:
>  v1 -> v2
>  Fixed return code in functions: setup_output_field()
>  and select_key() as pointed out by Namhyung.
> 
>  tools/perf/builtin-lock.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> index 208c482daa56..94a2bc15a2fa 100644
> --- a/tools/perf/builtin-lock.c
> +++ b/tools/perf/builtin-lock.c
> @@ -2049,7 +2049,8 @@ static int __cmd_contention(int argc, const char **argv)
>  				goto out_delete;
>  		}
>  
> -		if (lock_contention_prepare(&con) < 0) {
> +		err = lock_contention_prepare(&con);
> +		if (err < 0) {
>  			pr_err("lock contention BPF setup failed\n");
>  			goto out_delete;
>  		}
> @@ -2070,10 +2071,14 @@ static int __cmd_contention(int argc, const char **argv)
>  		}
>  	}
>  
> -	if (setup_output_field(true, output_fields))
> +	err = setup_output_field(true, output_fields);
> +	if (err) {
> +		pr_err("Failed to setup output field\n");
>  		goto out_delete;
> +	}
>  
> -	if (select_key(true))
> +	err = select_key(true);
> +	if (err)
>  		goto out_delete;
>  
>  	if (symbol_conf.field_sep) {
> -- 
> 2.43.5
>