2020-07-22 09:22:06

by Thomas Richter

Subject: [PATCH] Fix s390x compile error on F32 utils/stat-display.c

Fix a compile error on F32 and gcc version 10.1 on s390 in file
utils/stat-display.c. The error does not show up with make DEBUG=y.
In fact the issue shows up when using both compiler options
-O6 and -D_FORTIFY_SOURCE=2 (which are omitted with DEBUG=Y).

This is the offending call chain:
print_counter_aggr()
printout(config, -1, 0, ...) with 2nd parm id set to -1
aggr_printout(config, x, id --> -1, ...) which leads to this code:
case AGGR_NONE:
if (evsel->percore && !config->percore_show_thread) {
....
} else {
fprintf(config->output, "CPU%*d%s",
config->csv_output ? 0 : -7,
evsel__cpus(evsel)->map[id],
^^ id is -1 !!!!
config->csv_sep);
}

This is a compiler inlining issue which is detected on s390 but not on
other plattforms.

Output before:
# make util/stat-display.o
.....

util/stat-display.c: In function ‘perf_evlist__print_counters’:
util/stat-display.c:121:4: error: array subscript -1 is below array
bounds of ‘int[]’ [-Werror=array-bounds]
121 | fprintf(config->output, "CPU%*d%s",
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
122 | config->csv_output ? 0 : -7,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
123 | evsel__cpus(evsel)->map[id],
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
124 | config->csv_sep);
| ~~~~~~~~~~~~~~~~
In file included from util/evsel.h:13,
from util/evlist.h:13,
from util/stat-display.c:9:
/root/linux/tools/lib/perf/include/internal/cpumap.h:10:7:
note: while referencing ‘map’
10 | int map[];
| ^~~
cc1: all warnings being treated as errors
mv: cannot stat 'util/.stat-display.o.tmp': No such file or directory
make[3]: *** [/root/linux/tools/build/Makefile.build:97: util/stat-display.o]
Error 1
make[2]: *** [Makefile.perf:716: util/stat-display.o] Error 2
make[1]: *** [Makefile.perf:231: sub-make] Error 2
make: *** [Makefile:110: util/stat-display.o] Error 2
[root@t35lp46 perf]#

Output after:
# make util/stat-display.o
.....
CC util/stat-display.o
[root@t35lp46 perf]#

Signed-off-by: Thomas Richter <[email protected]>
---
tools/perf/util/stat-display.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 57d0706e1330..e49e544188e4 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -118,10 +118,11 @@ static void aggr_printout(struct perf_stat_config *config,
config->csv_output ? 0 : -3,
cpu_map__id_to_cpu(id), config->csv_sep);
} else {
- fprintf(config->output, "CPU%*d%s",
- config->csv_output ? 0 : -7,
- evsel__cpus(evsel)->map[id],
- config->csv_sep);
+ if (id > -1)
+ fprintf(config->output, "CPU%*d%s",
+ config->csv_output ? 0 : -7,
+ evsel__cpus(evsel)->map[id],
+ config->csv_sep);
}
break;
case AGGR_THREAD:
--
2.26.2

2020-08-12 11:30:03

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] Fix s390x compile error on F32 utils/stat-display.c

Em Wed, Jul 22, 2020 at 11:20:53AM +0200, Thomas Richter escreveu:
> Fix a compile error on F32 and gcc version 10.1 on s390 in file
> utils/stat-display.c. The error does not show up with make DEBUG=y.
> In fact the issue shows up when using both compiler options
> -O6 and -D_FORTIFY_SOURCE=2 (which are omitted with DEBUG=Y).
>
> This is the offending call chain:
> print_counter_aggr()
> printout(config, -1, 0, ...) with 2nd parm id set to -1
> aggr_printout(config, x, id --> -1, ...) which leads to this code:
> case AGGR_NONE:
> if (evsel->percore && !config->percore_show_thread) {
> ....
> } else {
> fprintf(config->output, "CPU%*d%s",
> config->csv_output ? 0 : -7,
> evsel__cpus(evsel)->map[id],
> ^^ id is -1 !!!!
> config->csv_sep);
> }
>
> This is a compiler inlining issue which is detected on s390 but not on
> other plattforms.

What is the sequence of events that gets to this? I.e. is it valid to
get a config->aggr_mode == AGGR_NONE, then have evsel not be percore and
config->percore_show_thread to be false?

I wonder if this won't be papering over some bug :-\

Jin?

This is where this came from:
commit 4fc4d8dfa056dfd48afe73b9ea3b7570ceb80b9c (tag: perf-core-for-mingo-5.2-20190517)
Author: Jin Yao <[email protected]>
Date: Fri Apr 12 21:59:49 2019 +0800

perf stat: Support 'percore' event qualifier

With this patch, we can use the 'percore' event qualifier in perf-stat.

---

Also please add at least Jiri and Namhyung on the CC list, having the
person that added that array usage also helps.

[acme@quaco perf]$ scripts/get_maintainer.pl tools/perf | grep reviewer
Mark Rutland <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
Alexander Shishkin <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
Jiri Olsa <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
Namhyung Kim <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
[acme@quaco perf]$

Thanks,

- Arnaldo

> Output before:
> # make util/stat-display.o
> .....
>
> util/stat-display.c: In function ‘perf_evlist__print_counters’:
> util/stat-display.c:121:4: error: array subscript -1 is below array
> bounds of ‘int[]’ [-Werror=array-bounds]
> 121 | fprintf(config->output, "CPU%*d%s",
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 122 | config->csv_output ? 0 : -7,
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 123 | evsel__cpus(evsel)->map[id],
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 124 | config->csv_sep);
> | ~~~~~~~~~~~~~~~~
> In file included from util/evsel.h:13,
> from util/evlist.h:13,
> from util/stat-display.c:9:
> /root/linux/tools/lib/perf/include/internal/cpumap.h:10:7:
> note: while referencing ‘map’
> 10 | int map[];
> | ^~~
> cc1: all warnings being treated as errors
> mv: cannot stat 'util/.stat-display.o.tmp': No such file or directory
> make[3]: *** [/root/linux/tools/build/Makefile.build:97: util/stat-display.o]
> Error 1
> make[2]: *** [Makefile.perf:716: util/stat-display.o] Error 2
> make[1]: *** [Makefile.perf:231: sub-make] Error 2
> make: *** [Makefile:110: util/stat-display.o] Error 2
> [root@t35lp46 perf]#
>
> Output after:
> # make util/stat-display.o
> .....
> CC util/stat-display.o
> [root@t35lp46 perf]#
>
> Signed-off-by: Thomas Richter <[email protected]>
> ---
> tools/perf/util/stat-display.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 57d0706e1330..e49e544188e4 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -118,10 +118,11 @@ static void aggr_printout(struct perf_stat_config *config,
> config->csv_output ? 0 : -3,
> cpu_map__id_to_cpu(id), config->csv_sep);
> } else {
> - fprintf(config->output, "CPU%*d%s",
> - config->csv_output ? 0 : -7,
> - evsel__cpus(evsel)->map[id],
> - config->csv_sep);
> + if (id > -1)
> + fprintf(config->output, "CPU%*d%s",
> + config->csv_output ? 0 : -7,
> + evsel__cpus(evsel)->map[id],
> + config->csv_sep);
> }
> break;
> case AGGR_THREAD:
> --
> 2.26.2
>

--

- Arnaldo

2020-08-24 14:46:33

by Thomas Richter

Subject: Re: [PATCH] Fix s390x compile error on F32 utils/stat-display.c

Hi Arnaldo, Jin, Jiri

any update on this issue?

Thanks.

On 8/12/20 1:27 PM, Arnaldo Carvalho de Melo wrote:
> Em Wed, Jul 22, 2020 at 11:20:53AM +0200, Thomas Richter escreveu:
>> Fix a compile error on F32 and gcc version 10.1 on s390 in file
>> utils/stat-display.c. The error does not show up with make DEBUG=y.
>> In fact the issue shows up when using both compiler options
>> -O6 and -D_FORTIFY_SOURCE=2 (which are omitted with DEBUG=Y).
>>
>> This is the offending call chain:
>> print_counter_aggr()
>> printout(config, -1, 0, ...) with 2nd parm id set to -1
>> aggr_printout(config, x, id --> -1, ...) which leads to this code:
>> case AGGR_NONE:
>> if (evsel->percore && !config->percore_show_thread) {
>> ....
>> } else {
>> fprintf(config->output, "CPU%*d%s",
>> config->csv_output ? 0 : -7,
>> evsel__cpus(evsel)->map[id],
>> ^^ id is -1 !!!!
>> config->csv_sep);
>> }
>>
>> This is a compiler inlining issue which is detected on s390 but not on
>> other plattforms.
>
> What is the sequence of events that gets to this? I.e. is it valid to
> get a config->aggr_mode == AGGR_NONE, then have evsel not be percore and
> config->percore_show_thread to be false?
>
> I wonder if this won't be papering over some bug :-\
>
> Jin?
>
> This is where this came from:
> commit 4fc4d8dfa056dfd48afe73b9ea3b7570ceb80b9c (tag: perf-core-for-mingo-5.2-20190517)
> Author: Jin Yao <[email protected]>
> Date: Fri Apr 12 21:59:49 2019 +0800
>
> perf stat: Support 'percore' event qualifier
>
> With this patch, we can use the 'percore' event qualifier in perf-stat.
>
> ---
>
> Also please add at least Jiri and Namhyung on the CC list, having the
> person that added that array usage also helps.
>
> [acme@quaco perf]$ scripts/get_maintainer.pl tools/perf | grep reviewer
> Mark Rutland <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> Alexander Shishkin <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> Jiri Olsa <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> Namhyung Kim <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> [acme@quaco perf]$
>
> Thanks,
>
> - Arnaldo
>
>> Output before:
>> # make util/stat-display.o
>> .....
>>
>> util/stat-display.c: In function ‘perf_evlist__print_counters’:
>> util/stat-display.c:121:4: error: array subscript -1 is below array
>> bounds of ‘int[]’ [-Werror=array-bounds]
>> 121 | fprintf(config->output, "CPU%*d%s",
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> 122 | config->csv_output ? 0 : -7,
>> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> 123 | evsel__cpus(evsel)->map[id],
>> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> 124 | config->csv_sep);
>> | ~~~~~~~~~~~~~~~~
>> In file included from util/evsel.h:13,
>> from util/evlist.h:13,
>> from util/stat-display.c:9:
>> /root/linux/tools/lib/perf/include/internal/cpumap.h:10:7:
>> note: while referencing ‘map’
>> 10 | int map[];
>> | ^~~
>> cc1: all warnings being treated as errors
>> mv: cannot stat 'util/.stat-display.o.tmp': No such file or directory
>> make[3]: *** [/root/linux/tools/build/Makefile.build:97: util/stat-display.o]
>> Error 1
>> make[2]: *** [Makefile.perf:716: util/stat-display.o] Error 2
>> make[1]: *** [Makefile.perf:231: sub-make] Error 2
>> make: *** [Makefile:110: util/stat-display.o] Error 2
>> [root@t35lp46 perf]#
>>
>> Output after:
>> # make util/stat-display.o
>> .....
>> CC util/stat-display.o
>> [root@t35lp46 perf]#
>>
>> Signed-off-by: Thomas Richter <[email protected]>
>> ---
>> tools/perf/util/stat-display.c | 9 +++++----
>> 1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
>> index 57d0706e1330..e49e544188e4 100644
>> --- a/tools/perf/util/stat-display.c
>> +++ b/tools/perf/util/stat-display.c
>> @@ -118,10 +118,11 @@ static void aggr_printout(struct perf_stat_config *config,
>> config->csv_output ? 0 : -3,
>> cpu_map__id_to_cpu(id), config->csv_sep);
>> } else {
>> - fprintf(config->output, "CPU%*d%s",
>> - config->csv_output ? 0 : -7,
>> - evsel__cpus(evsel)->map[id],
>> - config->csv_sep);
>> + if (id > -1)
>> + fprintf(config->output, "CPU%*d%s",
>> + config->csv_output ? 0 : -7,
>> + evsel__cpus(evsel)->map[id],
>> + config->csv_sep);
>> }
>> break;
>> case AGGR_THREAD:
>> --
>> 2.26.2
>>
>


--
Thomas Richter, Dept 3252, IBM s390 Linux Development, Boeblingen, Germany
--
Vorsitzender des Aufsichtsrats: Gregor Pillen
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294

2020-08-24 20:24:38

by Jiri Olsa

Subject: Re: [PATCH] Fix s390x compile error on F32 utils/stat-display.c

On Wed, Aug 12, 2020 at 08:27:08AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Wed, Jul 22, 2020 at 11:20:53AM +0200, Thomas Richter escreveu:
> > Fix a compile error on F32 and gcc version 10.1 on s390 in file
> > utils/stat-display.c. The error does not show up with make DEBUG=y.
> > In fact the issue shows up when using both compiler options
> > -O6 and -D_FORTIFY_SOURCE=2 (which are omitted with DEBUG=Y).
> >
> > This is the offending call chain:
> > print_counter_aggr()
> > printout(config, -1, 0, ...) with 2nd parm id set to -1
> > aggr_printout(config, x, id --> -1, ...) which leads to this code:
> > case AGGR_NONE:
> > if (evsel->percore && !config->percore_show_thread) {
> > ....
> > } else {
> > fprintf(config->output, "CPU%*d%s",
> > config->csv_output ? 0 : -7,
> > evsel__cpus(evsel)->map[id],
> > ^^ id is -1 !!!!
> > config->csv_sep);
> > }
> >
> > This is a compiler inlining issue which is detected on s390 but not on
> > other plattforms.
>
> What is the sequence of events that gets to this? I.e. is it valid to
> get a config->aggr_mode == AGGR_NONE, then have evsel not be percore and
> config->percore_show_thread to be false?
>
> I wonder if this won't be papering over some bug :-\
>
> Jin?
>
> This is where this came from:
> commit 4fc4d8dfa056dfd48afe73b9ea3b7570ceb80b9c (tag: perf-core-for-mingo-5.2-20190517)
> Author: Jin Yao <[email protected]>
> Date: Fri Apr 12 21:59:49 2019 +0800
>
> perf stat: Support 'percore' event qualifier
>
> With this patch, we can use the 'percore' event qualifier in perf-stat.
>
> ---
>
> Also please add at least Jiri and Namhyung on the CC list, having the
> person that added that array usage also helps.
>
> [acme@quaco perf]$ scripts/get_maintainer.pl tools/perf | grep reviewer
> Mark Rutland <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> Alexander Shishkin <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> Jiri Olsa <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> Namhyung Kim <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
> [acme@quaco perf]$
>
> Thanks,
>
> - Arnaldo
>
> > Output before:
> > # make util/stat-display.o
> > .....
> >
> > util/stat-display.c: In function ‘perf_evlist__print_counters’:
> > util/stat-display.c:121:4: error: array subscript -1 is below array
> > bounds of ‘int[]’ [-Werror=array-bounds]
> > 121 | fprintf(config->output, "CPU%*d%s",
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 122 | config->csv_output ? 0 : -7,
> > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 123 | evsel__cpus(evsel)->map[id],
> > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 124 | config->csv_sep);
> > | ~~~~~~~~~~~~~~~~
> > In file included from util/evsel.h:13,
> > from util/evlist.h:13,
> > from util/stat-display.c:9:
> > /root/linux/tools/lib/perf/include/internal/cpumap.h:10:7:
> > note: while referencing ‘map’
> > 10 | int map[];
> > | ^~~
> > cc1: all warnings being treated as errors
> > mv: cannot stat 'util/.stat-display.o.tmp': No such file or directory
> > make[3]: *** [/root/linux/tools/build/Makefile.build:97: util/stat-display.o]
> > Error 1
> > make[2]: *** [Makefile.perf:716: util/stat-display.o] Error 2
> > make[1]: *** [Makefile.perf:231: sub-make] Error 2
> > make: *** [Makefile:110: util/stat-display.o] Error 2
> > [root@t35lp46 perf]#

I tested on s390 with rhel8, but did not get this error,
f32's gcc must be smarter

> >
> > Output after:
> > # make util/stat-display.o
> > .....
> > CC util/stat-display.o
> > [root@t35lp46 perf]#
> >
> > Signed-off-by: Thomas Richter <[email protected]>
> > ---
> > tools/perf/util/stat-display.c | 9 +++++----
> > 1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> > index 57d0706e1330..e49e544188e4 100644
> > --- a/tools/perf/util/stat-display.c
> > +++ b/tools/perf/util/stat-display.c
> > @@ -118,10 +118,11 @@ static void aggr_printout(struct perf_stat_config *config,
> > config->csv_output ? 0 : -3,
> > cpu_map__id_to_cpu(id), config->csv_sep);
> > } else {
> > - fprintf(config->output, "CPU%*d%s",
> > - config->csv_output ? 0 : -7,
> > - evsel__cpus(evsel)->map[id],
> > - config->csv_sep);
> > + if (id > -1)
> > + fprintf(config->output, "CPU%*d%s",
> > + config->csv_output ? 0 : -7,
> > + evsel__cpus(evsel)->map[id],
> > + config->csv_sep);

-1 is only through print_counter_aggr which is called for AGGR_GLOBAL
case as you described, but I guess we can have this check as precaution

you could put it together with above else

} else if (id > -1)

thanks,
jirka

2020-08-25 08:48:26

by Thomas Richter

Subject: Re: [PATCH] Fix s390x compile error on F32 utils/stat-display.c

On 8/24/20 10:22 PM, Jiri Olsa wrote:
> On Wed, Aug 12, 2020 at 08:27:08AM -0300, Arnaldo Carvalho de Melo wrote:
>> Em Wed, Jul 22, 2020 at 11:20:53AM +0200, Thomas Richter escreveu:
>>> Fix a compile error on F32 and gcc version 10.1 on s390 in file
>>> utils/stat-display.c. The error does not show up with make DEBUG=y.
>>> In fact the issue shows up when using both compiler options
>>> -O6 and -D_FORTIFY_SOURCE=2 (which are omitted with DEBUG=Y).
>>>
>>> This is the offending call chain:
>>> print_counter_aggr()
>>> printout(config, -1, 0, ...) with 2nd parm id set to -1
>>> aggr_printout(config, x, id --> -1, ...) which leads to this code:
>>> case AGGR_NONE:
>>> if (evsel->percore && !config->percore_show_thread) {
>>> ....
>>> } else {
>>> fprintf(config->output, "CPU%*d%s",
>>> config->csv_output ? 0 : -7,
>>> evsel__cpus(evsel)->map[id],
>>> ^^ id is -1 !!!!
>>> config->csv_sep);
>>> }
>>>
>>> This is a compiler inlining issue which is detected on s390 but not on
>>> other plattforms.
>>
>> What is the sequence of events that gets to this? I.e. is it valid to
>> get a config->aggr_mode == AGGR_NONE, then have evsel not be percore and
>> config->percore_show_thread to be false?
>>
>> I wonder if this won't be papering over some bug :-\
>>
>> Jin?
>>
>> This is where this came from:
>> commit 4fc4d8dfa056dfd48afe73b9ea3b7570ceb80b9c (tag: perf-core-for-mingo-5.2-20190517)
>> Author: Jin Yao <[email protected]>
>> Date: Fri Apr 12 21:59:49 2019 +0800
>>
>> perf stat: Support 'percore' event qualifier
>>
>> With this patch, we can use the 'percore' event qualifier in perf-stat.
>>
>> ---
>>
>> Also please add at least Jiri and Namhyung on the CC list, having the
>> person that added that array usage also helps.
>>
>> [acme@quaco perf]$ scripts/get_maintainer.pl tools/perf | grep reviewer
>> Mark Rutland <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
>> Alexander Shishkin <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
>> Jiri Olsa <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
>> Namhyung Kim <[email protected]> (reviewer:PERFORMANCE EVENTS SUBSYSTEM)
>> [acme@quaco perf]$
>>
>> Thanks,
>>
>> - Arnaldo
>>
>>> Output before:
>>> # make util/stat-display.o
>>> .....
>>>
>>> util/stat-display.c: In function ‘perf_evlist__print_counters’:
>>> util/stat-display.c:121:4: error: array subscript -1 is below array
>>> bounds of ‘int[]’ [-Werror=array-bounds]
>>> 121 | fprintf(config->output, "CPU%*d%s",
>>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> 122 | config->csv_output ? 0 : -7,
>>> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> 123 | evsel__cpus(evsel)->map[id],
>>> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> 124 | config->csv_sep);
>>> | ~~~~~~~~~~~~~~~~
>>> In file included from util/evsel.h:13,
>>> from util/evlist.h:13,
>>> from util/stat-display.c:9:
>>> /root/linux/tools/lib/perf/include/internal/cpumap.h:10:7:
>>> note: while referencing ‘map’
>>> 10 | int map[];
>>> | ^~~
>>> cc1: all warnings being treated as errors
>>> mv: cannot stat 'util/.stat-display.o.tmp': No such file or directory
>>> make[3]: *** [/root/linux/tools/build/Makefile.build:97: util/stat-display.o]
>>> Error 1
>>> make[2]: *** [Makefile.perf:716: util/stat-display.o] Error 2
>>> make[1]: *** [Makefile.perf:231: sub-make] Error 2
>>> make: *** [Makefile:110: util/stat-display.o] Error 2
>>> [root@t35lp46 perf]#
>
> I tested on s390 with rhel8, but did not get this error,
> f32's gcc must be smarter
>

i Jiri,

that is correct. I have installed Fedora 32 on my LPAR and the gcc version
is:
[root@t35lp46 ~]# gcc --version
gcc (GCC) 10.1.1 20200507 (Red Hat 10.1.1-1)
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[root@t35lp46 ~]# cat /etc/redhat-release
Fedora release 32 (Thirty Two)
[root@t35lp46 ~]#

Same commands on a RHEL 8.2 installation reveal
[root@m35lp76 ~]# gcc --version
gcc (GCC) 8.3.1 20191121 (Red Hat 8.3.1-5)
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[root@m35lp76 ~]# cat /etc/redhat-release
Red Hat Enterprise Linux release 8.2 Beta (Ootpa)
[root@m35lp76 ~]#

So there are 2 major revisions difference between a F32 and a RHEL8
gcc compiler installation.

>>>
>>> Output after:
>>> # make util/stat-display.o
>>> .....
>>> CC util/stat-display.o
>>> [root@t35lp46 perf]#
>>>
>>> Signed-off-by: Thomas Richter <[email protected]>
>>> ---
>>> tools/perf/util/stat-display.c | 9 +++++----
>>> 1 file changed, 5 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
>>> index 57d0706e1330..e49e544188e4 100644
>>> --- a/tools/perf/util/stat-display.c
>>> +++ b/tools/perf/util/stat-display.c
>>> @@ -118,10 +118,11 @@ static void aggr_printout(struct perf_stat_config *config,
>>> config->csv_output ? 0 : -3,
>>> cpu_map__id_to_cpu(id), config->csv_sep);
>>> } else {
>>> - fprintf(config->output, "CPU%*d%s",
>>> - config->csv_output ? 0 : -7,
>>> - evsel__cpus(evsel)->map[id],
>>> - config->csv_sep);
>>> + if (id > -1)
>>> + fprintf(config->output, "CPU%*d%s",
>>> + config->csv_output ? 0 : -7,
>>> + evsel__cpus(evsel)->map[id],
>>> + config->csv_sep);
>
> -1 is only through print_counter_aggr which is called for AGGR_GLOBAL
> case as you described, but I guess we can have this check as precaution
>
> you could put it together with above else
>
> } else if (id > -1)
>
> thanks,
> jirka
>

As suggested I will send a new patch.

--
Thomas Richter, Dept 3252, IBM s390 Linux Development, Boeblingen, Germany
--
Vorsitzender des Aufsichtsrats: Gregor Pillen
Geschäftsführung: Dirk Wittkopp
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