Hi all,
As I did not get a reply from Stephane I would like to turn this to the
perfmon2-devel mailing list.
Please see the text below:
Hi Stephane,
I would like to ask for your help.
There is a build problem of PAPI when using gcc/8.
See open issue here:
https://bitbucket.org/icl/papi/issues/51/build-failed-using-gcc-810
<https://bitbucket.org/icl/papi/issues/51/build-failed-using-gcc-810>
This issue can be fixed very easily by just increasing the buffer size.
As this is part of libpfm4 I would like to address this to you.
The main reason for the build failure is that PAPI converts warnings to errors,
see:
-Werror (Make the specified warning into an error)
-Wformat-truncation (Warn about calls to formatted input/output functions such
as snprintf and vsnprintf that might result in output truncation)
And the latest gcc versions message warnings for snprintf if the buffer is too
small and output might be truncated.
Here a small example:
cat test.c:
int main()
{
char dirname[256];
char filename[256];
strcpy(dirname,"/ccs/home/winklerf/sources");
strcpy(filename,"frank.txt");
char pathname[256];
snprintf(pathname, sizeof(pathname), "%s/%s", dirname, filename);
puts(pathname);
return 0;
}
gcc -Werror -Wformat-truncation test.c -o test
[winklerf@login3.summit <mailto:winklerf@login3.summit> sources]$ gcc -Werror
-Wformat-truncation test.c -o test
test.c: In function 'main':
test.c:17:43: error: '%s' directive output may be truncated writing up to 255
bytes into a region of size between 0 and 255 [-Werror=format-truncation=]
snprintf(pathname, sizeof pathname, "%s/%s", dirname, filename);
^~ ~~~~~~~~
test.c:17:3: note: 'snprintf' output between 2 and 512 bytes into a destination
of size 256
snprintf(pathname, sizeof pathname, "%s/%s", dirname, filename);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
The same happens with PAPI when building with gcc/8:
make[2]: Entering directory
`/autofs/nccs-svm1_home2/winklerf/sources/papi-5.6.0/src/libpfm4/lib'
gcc -Wno-override-init -g -Wall -Werror -Wextra -Wno-unused-parameter -I.
-I/autofs/nccs-svm1_home2/winklerf/sources/papi-5.6.0/src/libpfm4/lib/../include
-DCONFIG_PFMLIB_DEBUG -DCONFIG_PFMLIB_OS_LINUX -D_REENTRANT -I.
-fvisibility=hidden -DCONFIG_PFMLIB_ARCH_POWERPC -I. -c pfmlib_common.c
gcc -Wno-override-init -g -Wall -Werror -Wextra -Wno-unused-parameter -I.
-I/autofs/nccs-svm1_home2/winklerf/sources/papi-5.6.0/src/libpfm4/lib/../include
-DCONFIG_PFMLIB_DEBUG -DCONFIG_PFMLIB_OS_LINUX -D_REENTRANT -I.
-fvisibility=hidden -DCONFIG_PFMLIB_ARCH_POWERPC -I. -c pfmlib_perf_event_pmu.c
pfmlib_perf_event_pmu.c: In function 'gen_tracepoint_table':
pfmlib_perf_event_pmu.c:349:36: error: '%s' directive output may be truncated
writing up to 255 bytes into a region of size between 0 and 4095
[-Werror=format-truncation=]
snprintf(d2path, MAXPATHLEN, "%s/%s", debugfs_mnt, d1->d_name);
^~
pfmlib_perf_event_pmu.c:349:3: note: 'snprintf' output between 2 and 4352 bytes
into a destination of size 4096
snprintf(d2path, MAXPATHLEN, "%s/%s", debugfs_mnt, d1->d_name);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pfmlib_perf_event_pmu.c:399:58: error: '%s' directive output may be truncated
writing up to 255 bytes into a region of size between 0 and 4095
[-Werror=format-truncation=]
snprintf(idpath, MAXPATHLEN, "%s/%s/id", d2path,
d2->d_name);
^~
pfmlib_perf_event_pmu.c:399:25: note: 'snprintf' output between 5 and 4355
bytes into a destination of size 4096
snprintf(idpath, MAXPATHLEN, "%s/%s/id", d2path,
d2->d_name);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
The 2 lines of the following file have to be fixed:
vi src/libpfm4/lib/pfmlib_perf_event_pmu.c
349 snprintf(d2path, MAXPATHLEN + 256, "%s/%s", debugfs_mnt,
d1->d_name);
399 snprintf(idpath, MAXPATHLEN + 3 + 256, "%s/%s/id",
d2path, d2->d_name);
There should be a more general fix, of course. But this is up to you, maybe
just increase MAXPATHLEN...
Thanks
Frank_______________________________________________
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