[tip:perf/core] perf stat: Avoid segfaults caused by negated options

[tip-bot for Michael Petlan <tipbot@xxxxxxxxx>]

Commit-ID:  51433ead1460fb3f46e1c34f68bb22fd2dd0f5d0
Gitweb:     https://git.kernel.org/tip/51433ead1460fb3f46e1c34f68bb22fd2dd0f5d0
Author:     Michael Petlan <mpetlan@xxxxxxxxxx>
AuthorDate: Mon, 10 Dec 2018 11:00:04 -0500
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 18 Dec 2018 12:21:44 -0300

perf stat: Avoid segfaults caused by negated options

Some 'perf stat' options do not make sense to be negated (event,
cgroup), some do not have negated path implemented (metrics). Due to
that, it is better to disable the "no-" prefix for them, since
otherwise, the later opt-parsing segfaults.

Before:

  $ perf stat --no-metrics -- ls
  Segmentation fault (core dumped)

After:

  $ perf stat --no-metrics -- ls
   Error: option `no-metrics' isn't available
   Usage: perf stat [<options>] [<command>]

Signed-off-by: Michael Petlan <mpetlan@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
LPU-Reference: 1485912065.62416880.1544457604340.JavaMail.zimbra@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-stat.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a635abfa77b6..1410d66192f7 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -709,7 +709,7 @@ static int parse_metric_groups(const struct option *opt,
 	return metricgroup__parse_groups(opt, str, &stat_config.metric_events);
 }
 
-static const struct option stat_options[] = {
+static struct option stat_options[] = {
 	OPT_BOOLEAN('T', "transaction", &transaction_run,
 		    "hardware transaction statistics"),
 	OPT_CALLBACK('e', "event", &evsel_list, "event",
@@ -1599,6 +1599,12 @@ int cmd_stat(int argc, const char **argv)
 		return -ENOMEM;
 
 	parse_events__shrink_config_terms();
+
+	/* String-parsing callback-based options would segfault when negated */
+	set_option_flag(stat_options, 'e', "event", PARSE_OPT_NONEG);
+	set_option_flag(stat_options, 'M', "metrics", PARSE_OPT_NONEG);
+	set_option_flag(stat_options, 'G', "cgroup", PARSE_OPT_NONEG);
+
 	argc = parse_options_subcommand(argc, argv, stat_options, stat_subcommands,
 					(const char **) stat_usage,
 					PARSE_OPT_STOP_AT_NON_OPTION);