313146a844
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]#
Committer notes:
Removed the removal of {} enclosing the multiline else block, as pointed
out by Jiri Olsa.
Suggested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20200825063304.77733-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.