• Thomas Richter's avatar
    perf stat: Fix out of bounds array access in the print_counters() evlist method · 313146a8
    Thomas Richter authored
    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: default avatarJiri Olsa <jolsa@redhat.com>
    Signed-off-by: default avatarThomas Richter <tmricht@linux.ibm.com>
    Acked-by: default avatarJiri 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.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    313146a8
stat-display.c 30.5 KB