Re: [PATCH v2] perf script: Fix overrun issue for dynamically-allocated pmu type number

[Jin, Yao]

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@xxxxxxxxxxxxxxx>
>
> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

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)