Re: [PATCH] perf/tool: Fix usage of trace events with '-' in trace system name.

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 17/04/14 16:40, Jiri Olsa wrote:
> On Mon, Mar 24, 2014 at 09:49:00PM +0100, Christian Borntraeger wrote:
>> From: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
>>
>> Trace events potentially can have a '-' in their trace system name,
>> e.g. kvm on s390 defines kvm-s390:* tracepoints.
>> tools/perf could not parse them, because there was no rule for this:
>> $ sudo ./perf top -e "kvm-s390:*"
>> invalid or unsupported event: 'kvm-s390:*'
>>
>> This patch adds an extra rule to event_legacy_tracepoint which handles
>> those cases. Without the patch, perf will not accept such tracepoints in
>> the -e option.
>>
>> Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>  tools/perf/util/parse-events.y | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
>> index 4eb67ec..dbbb01c 100644
>> --- a/tools/perf/util/parse-events.y
>> +++ b/tools/perf/util/parse-events.y
>> @@ -299,6 +299,18 @@ PE_PREFIX_MEM PE_VALUE sep_dc
>>  }
>>  
>>  event_legacy_tracepoint:
>> +PE_NAME '-' PE_NAME ':' PE_NAME
>> +{
>> +	struct parse_events_evlist *data = _data;
>> +	struct list_head *list;
>> +	char sys_name[strlen($1) + strlen($3) + 2];
> 
> hum, could you limit the size of sys_name array with some
> sane value? those strlens make me nervous :-\

Right. Something like
char sys_name[128];
[...]

snprintf(&sys_name, 128, "%s-%s", $1, $3);

should be enough for all trace event names. And if not, the event should simply fail.

Alexander,

can you send an updates patch?