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

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

[Athira Rajeev]

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@linux.vnet.ibm.com>
---
 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

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

[Athira Rajeev]

> On 23 Dec 2024, at 7:26 PM, Athira Rajeev <atrajeev@linux.vnet.ibm.com> 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@linux.vnet.ibm.com>

Hi,

Looking for review comments on this

Athira

> ---
> 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
> 

Re: [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@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
> 

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

[Athira Rajeev]

> On 7 Jan 2025, at 2:45 AM, Namhyung Kim <namhyung@kernel.org> wrote:
> 
> 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@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

Hi Namhyung

Thanks for reviewing and pointing out setup_output_field() and select_key()
I will send a V2 with handling return code for these two functions as well

Thanks
Athira 
> 
> 
>> ---
>> 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 	(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