[PATCH] tools/perf: Fix return code for lock_contention_prepare

[Namhyung Kim]

Hello,

On Mon, Dec 23, 2024 at 07:26:55PM +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
> 
> Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>

Thanks for the fix, the change itself looks good but I think we need the
same for setup_output_field() and select_key() as well.

Thanks,
Namhyung


> ---
>  tools/perf/builtin-lock.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> index 208c482daa56..2226c7dd4ae6 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;
>  		}
> -- 
> 2.43.5
>