diff mbox series

[perf/core: Update sample_flags for raw_data in perf_output_sample

Message ID 20221020070657.21571-1-atrajeev@linux.vnet.ibm.com
State New
Headers
Series [perf/core: Update sample_flags for raw_data in perf_output_sample |

Commit Message

Athira Rajeev Oct. 20, 2022, 7:06 a.m. UTC 
  commit 838d9bb62d13 ("perf: Use sample_flags for raw_data")
added check for PERF_SAMPLE_RAW in sample_flags in
perf_prepare_sample(). But while copying the sample in memory,
the check for sample_flags is not added in perf_output_sample().
Fix adds the same in perf_output_sample as well.

Fixes: 838d9bb62d13 ("perf: Use sample_flags for raw_data")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Peter Zijlstra Oct. 20, 2022, 2:40 p.m. UTC | #1 
On Thu, Oct 20, 2022 at 12:36:56PM +0530, Athira Rajeev wrote:
> commit 838d9bb62d13 ("perf: Use sample_flags for raw_data")
> added check for PERF_SAMPLE_RAW in sample_flags in
> perf_prepare_sample(). But while copying the sample in memory,
> the check for sample_flags is not added in perf_output_sample().
> Fix adds the same in perf_output_sample as well.
> 
> Fixes: 838d9bb62d13 ("perf: Use sample_flags for raw_data")
> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
> ---
>  kernel/events/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 4ec3717003d5..daf387c75d33 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -7099,7 +7099,7 @@ void perf_output_sample(struct perf_output_handle *handle,
>  	if (sample_type & PERF_SAMPLE_RAW) {
>  		struct perf_raw_record *raw = data->raw;
>  
> -		if (raw) {
> +		if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) {
>  			struct perf_raw_frag *frag = &raw->frag;
>  
>  			perf_output_put(handle, raw->size);

Urgh.. something smells here. We already did a PERF_SAMPLE_RAW test.

And perf_prepare_sample() explicitly makes data->raw be NULL when not
set earlier.

So what's going wrong?
Athira Rajeev Nov. 2, 2022, 8:19 a.m. UTC | #2 
> On 20-Oct-2022, at 8:10 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> 
> On Thu, Oct 20, 2022 at 12:36:56PM +0530, Athira Rajeev wrote:
>> commit 838d9bb62d13 ("perf: Use sample_flags for raw_data")
>> added check for PERF_SAMPLE_RAW in sample_flags in
>> perf_prepare_sample(). But while copying the sample in memory,
>> the check for sample_flags is not added in perf_output_sample().
>> Fix adds the same in perf_output_sample as well.
>> 
>> Fixes: 838d9bb62d13 ("perf: Use sample_flags for raw_data")
>> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
>> ---
>> kernel/events/core.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>> index 4ec3717003d5..daf387c75d33 100644
>> --- a/kernel/events/core.c
>> +++ b/kernel/events/core.c
>> @@ -7099,7 +7099,7 @@ void perf_output_sample(struct perf_output_handle *handle,
>> 	if (sample_type & PERF_SAMPLE_RAW) {
>> 		struct perf_raw_record *raw = data->raw;
>> 
>> -		if (raw) {
>> +		if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) {
>> 			struct perf_raw_frag *frag = &raw->frag;
>> 
>> 			perf_output_put(handle, raw->size);
> 
> Urgh.. something smells here. We already did a PERF_SAMPLE_RAW test.
> 
> And perf_prepare_sample() explicitly makes data->raw be NULL when not
> set earlier.
> 
> So what's going wrong?

Hi Peter,

Sorry for late response. I was out on vacation couple of days.

I didn't hit any specific issue or fail with current code. But patch intention was
to keep the perf_prepare_sample and perf_output_sample to be in sync with the checks that we
are doing.

Thanks
Athira
diff mbox series

Patch

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4ec3717003d5..daf387c75d33 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7099,7 +7099,7 @@  void perf_output_sample(struct perf_output_handle *handle,
 	if (sample_type & PERF_SAMPLE_RAW) {
 		struct perf_raw_record *raw = data->raw;
 
-		if (raw) {
+		if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) {
 			struct perf_raw_frag *frag = &raw->frag;
 
 			perf_output_put(handle, raw->size);