[PATCH v3] perf trace: Segfault when trying to trace events by cgroup

[Stanislav Ivanichkin]

 # ./perf trace -e sched:sched_switch -G test -a sleep 1
 perf: Segmentation fault
 Obtained 11 stack frames.
 ./perf(sighandler_dump_stack+0x43) [0x55cfdc636db3]
 /lib/x86_64-linux-gnu/libc.so.6(+0x3efcf) [0x7fd23eecafcf]
 ./perf(parse_cgroups+0x36) [0x55cfdc673f36]
 ./perf(+0x3186ed) [0x55cfdc70d6ed]
 ./perf(parse_options_subcommand+0x629) [0x55cfdc70e999]
 ./perf(cmd_trace+0x9c2) [0x55cfdc5ad6d2]
 ./perf(+0x1e8ae0) [0x55cfdc5ddae0]
 ./perf(+0x1e8ded) [0x55cfdc5ddded]
 ./perf(main+0x370) [0x55cfdc556f00]
 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6) [0x7fd23eeadb96]
 ./perf(_start+0x29) [0x55cfdc557389]
 Segmentation fault

 It happens because "struct trace" in option->value is passed to
 parse_cgroups function instead of "struct evlist".

 v3:
   - missed commit message (Namhyung Kim)

 v2:
   - struct declaration fixed (Namhyung Kim)

Fixes: 9ea42ba4411ac ("perf trace: Support setting cgroups as targets")
Signed-off-by: Stanislav Ivanichkin <sivanich...@yandex-team.ru>
Acked-by: Namhyung Kim <namhy...@kernel.org>
---
 tools/perf/builtin-trace.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 44a75f234db1..de80534473af 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -4639,9 +4639,9 @@ static int trace__parse_events_option(const struct option 
*opt, const char *str,
        err = 0;
 
        if (lists[0]) {
-               struct option o = OPT_CALLBACK('e', "event", &trace->evlist, 
"event",
-                                              "event selector. use 'perf list' 
to list available events",
-                                              parse_events_option);
+               struct option o = {
+                       .value = &trace->evlist,
+               };
                err = parse_events_option(&o, lists[0], 0);
        }
 out:
@@ -4655,9 +4655,12 @@ static int trace__parse_cgroups(const struct option 
*opt, const char *str, int u
 {
        struct trace *trace = opt->value;
 
-       if (!list_empty(&trace->evlist->core.entries))
-               return parse_cgroups(opt, str, unset);
-
+       if (!list_empty(&trace->evlist->core.entries)) {
+               struct option o = {
+                       .value = &trace->evlist,
+               };
+               return parse_cgroups(&o, str, unset);
+       }
        trace->cgroup = evlist__findnew_cgroup(trace->evlist, str);
 
        return 0;
-- 
2.17.1