Re: [PATCH] perf jevents: Fix event code for events referencing std arch events

[John Garry <john.garry@huawei.com>]

On 12/10/2020 11:54, Jiri Olsa wrote:
>> ff --git a/tools/perf/pmu-events/jevents.c b/tools/perf/pmu-events/jevents.c
>> index 99df41a9543d..e47644cab3fa 100644
>> --- a/tools/perf/pmu-events/jevents.c
>> +++ b/tools/perf/pmu-events/jevents.c
>> @@ -505,20 +505,15 @@ static char *real_event(const char *name, char *event)
>>   }
>>   
>>   static int
>> -try_fixup(const char *fn, char *arch_std, unsigned long long eventcode,
>> -	  struct json_event *je)
>> +try_fixup(const char *fn, char *arch_std, struct json_event *je, char **event)
>>   {
>>   	/* try to find matching event from arch standard values */
>>   	struct event_struct *es;
>>   
>>   	list_for_each_entry(es, &arch_std_events, list) {
>>   		if (!strcmp(arch_std, es->name)) {
>> -			if (!eventcode && es->event) {
>> -				/* allow EventCode to be overridden */
>> -				free(je->event);
>> -				je->event = NULL;
>> -			}
>>   			FOR_ALL_EVENT_STRUCT_FIELDS(TRY_FIXUP_FIELD);
>> +			*event = je->event;
> I'm bit rusty on this code, 
> but isn't je->event NULL at this point?

je->event should be now assigned from es->event because of 
FOR_ALL_EVENT_STRUCT_FIELDS(TRY_FIXUP_FIELD):

#define TRY_FIXUP_FIELD(field) do { if (es->field && !*field) {\
	*field = strdup(es->field);				\
	if (!*field)						\
		return -ENOMEM;					\
} } while (0)

And es->event should be set.

Thanks,
John