perf tools: Fix a bug of segmentation fault
Fix the 'segmentation fault' bug of 'perf list --list-cmds', which also
happens in other cases (e.g. record, report ...). This bug happens when
there are no cmds to list at all.
Example:
Before this patch:
$ perf list --list-cmds
Segmentation fault
$
After this patch:
$ perf list --list-cmds
$
As shown above, the result prints nothing rather than a segmentation
fault. The null result means 'perf list' has no cmds to display at this
time.
Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1423833115-11199-5-git-send-email-yunlong.song@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
index 4a015f7..4ee9a86 100644
--- a/tools/perf/util/parse-options.c
+++ b/tools/perf/util/parse-options.c
@@ -510,8 +510,10 @@
}
exit(130);
case PARSE_OPT_LIST_SUBCMDS:
- for (int i = 0; subcommands[i]; i++)
- printf("%s ", subcommands[i]);
+ if (subcommands) {
+ for (int i = 0; subcommands[i]; i++)
+ printf("%s ", subcommands[i]);
+ }
exit(130);
default: /* PARSE_OPT_UNKNOWN */
if (ctx.argv[0][1] == '-') {
