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Subject: Re: [PATCH v2] perf script: Fix overrun issue for
 dynamically-allocated pmu type number
To:     Adrian Hunter <adrian.hunter@intel.com>, acme@kernel.org,
        jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com,
        alexander.shishkin@linux.intel.com
Cc:     Linux-kernel@vger.kernel.org, ak@linux.intel.com,
        kan.liang@intel.com, yao.jin@intel.com
References: <20201209005828.21302-1-yao.jin@linux.intel.com>
 <3fcdc860-d858-0166-de23-34fc6fe5c1cd@intel.com>
From:   "Jin, Yao" <yao.jin@linux.intel.com>
Message-ID: <18fde68f-0d24-5bcb-38e1-11dcf6f70bc1@linux.intel.com>
Date:   Fri, 25 Dec 2020 09:10:23 +0800
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Hi Arnaldo, Jiri,

On 12/11/2020 2:10 PM, Adrian Hunter wrote:
> On 9/12/20 2:58 am, Jin Yao wrote:
>> When unpacking the event which is from dynamic pmu, the array
>> output[OUTPUT_TYPE_MAX] may be overrun. For example, type number of
>> SKL uncore_imc is 10, but OUTPUT_TYPE_MAX is 7 now (OUTPUT_TYPE_MAX =
>> PERF_TYPE_MAX + 1).
>>
>> /* In builtin-script.c */
>> process_event()
>> {
>>          unsigned int type = output_type(attr->type);
>>
>>          if (output[type].fields == 0)
>>                  return;
>> }
>>
>> output[10] is overrun.
>>
>> Create a type OUTPUT_TYPE_OTHER for dynamic pmu events, then
>> output_type(attr->type) will return OUTPUT_TYPE_OTHER here.
>>
>> Note that if PERF_TYPE_MAX ever changed, then there would be a conflict
>> between old perf.data files that had a dynamicaliy allocated PMU number
>> that would then be the same as a fixed PERF_TYPE.
>>
>> Example:
>>
>> perf record --switch-events -C 0 -e "{cpu-clock,uncore_imc/data_reads/,uncore_imc/data_writes/}:SD" -a -- sleep 1
>> perf script
>>
>> Before:
>>           swapper     0 [000] 1479253.987551:     277766               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.987797:     246709               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.988127:     329883               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.988273:     146393               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.988523:     249977               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.988877:     354090               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.989023:     145940               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.989383:     359856               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1479253.989523:     140082               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>
>> After:
>>           swapper     0 [000] 1397040.402011:     272384               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1397040.402011:       5396  uncore_imc/data_reads/:
>>           swapper     0 [000] 1397040.402011:        967 uncore_imc/data_writes/:
>>           swapper     0 [000] 1397040.402259:     249153               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1397040.402259:       7231  uncore_imc/data_reads/:
>>           swapper     0 [000] 1397040.402259:       1297 uncore_imc/data_writes/:
>>           swapper     0 [000] 1397040.402508:     249108               cpu-clock:  ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
>>           swapper     0 [000] 1397040.402508:       5333  uncore_imc/data_reads/:
>>           swapper     0 [000] 1397040.402508:       1008 uncore_imc/data_writes/:
>>
>> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> 
> Acked-by: Adrian Hunter <adrian.hunter@intel.com>
> 

Can this patch be accepted? :)

Thanks
Jin Yao

>> ---
>> v2:
>>    Remove Fixes tag because this issue has always been here, not caused by
>>    1405720d4f26 ("perf script: Add 'synth' event type for synthesized events").
>>    No functional change in v2.
>>   
>>   tools/perf/builtin-script.c | 18 +++++++++++++++++-
>>   1 file changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
>> index 1c322c129185..5d8a64836228 100644
>> --- a/tools/perf/builtin-script.c
>> +++ b/tools/perf/builtin-script.c
>> @@ -183,6 +183,7 @@ struct output_option {
>>   
>>   enum {
>>   	OUTPUT_TYPE_SYNTH = PERF_TYPE_MAX,
>> +	OUTPUT_TYPE_OTHER,
>>   	OUTPUT_TYPE_MAX
>>   };
>>   
>> @@ -279,6 +280,18 @@ static struct {
>>   
>>   		.invalid_fields = PERF_OUTPUT_TRACE | PERF_OUTPUT_BPF_OUTPUT,
>>   	},
>> +
>> +	[OUTPUT_TYPE_OTHER] = {
>> +		.user_set = false,
>> +
>> +		.fields = PERF_OUTPUT_COMM | PERF_OUTPUT_TID |
>> +			      PERF_OUTPUT_CPU | PERF_OUTPUT_TIME |
>> +			      PERF_OUTPUT_EVNAME | PERF_OUTPUT_IP |
>> +			      PERF_OUTPUT_SYM | PERF_OUTPUT_SYMOFFSET |
>> +			      PERF_OUTPUT_DSO | PERF_OUTPUT_PERIOD,
>> +
>> +		.invalid_fields = PERF_OUTPUT_TRACE | PERF_OUTPUT_BPF_OUTPUT,
>> +	},
>>   };
>>   
>>   struct evsel_script {
>> @@ -339,8 +352,11 @@ static inline int output_type(unsigned int type)
>>   	case PERF_TYPE_SYNTH:
>>   		return OUTPUT_TYPE_SYNTH;
>>   	default:
>> -		return type;
>> +		if (type < PERF_TYPE_MAX)
>> +			return type;
>>   	}
>> +
>> +	return OUTPUT_TYPE_OTHER;
>>   }
>>   
>>   static inline unsigned int attr_type(unsigned int type)
>>
>