On Sun, Nov 28, 2021 at 7:47 AM Jiri Olsa [off-list ref] wrote:

On Thu, Nov 18, 2021 at 12:17:30PM -0800, Ian Rogers wrote:

quoted

These leaks were found with leak sanitizer running "perf pipe recording
and injection test". In pipe mode feat_fd may hold onto an events struct
that needs freeing. When string features are processed they may
overwrite an already created string, so free this before the overwrite.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/header.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 79cce216727e..e3c1a532d059 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c

@@ -2321,6 +2321,7 @@ static int perf_header__read_build_ids(struct perf_header *header,
 #define FEAT_PROCESS_STR_FUN(__feat, __feat_env) \
 static int process_##__feat(struct feat_fd *ff, void *data __maybe_unused) \
 {\
+     free(ff->ph->env.__feat_env);                \

hm, how is this set before this callback is triggered?

I see it for cpuid which is initially set in:
#0  perf_env__read_cpuid (env=0x62b000007240) at util/env.c:363
#1  0x0000555556325153 in perf_env__cpuid (env=0x62b000007240) at util/env.c:456
#2  0x00005555564002ff in evlist__init_trace_event_sample_raw
(evlist=0x61e000000080) at util/sample-raw.c:17
#3  0x00005555563f01f4 in __perf_session__new (data=0x7fffffffb8b0,
repipe=false, repipe_fd=-1, tool=0x7fffffffbaa0)
    at util/session.c:228
#4  0x000055555615f26b in perf_session__new (data=0x7fffffffb8b0,
tool=0x7fffffffbaa0) at util/session.h:70
#5  0x000055555616d991 in cmd_report (argc=0, argv=0x7fffffffe468) at
builtin-report.c:1408
#6  0x00005555562f36b8 in run_builtin (p=0x5555586bacd0
<commands+240>, argc=5, argv=0x7fffffffe468) at perf.c:313
#7  0x00005555562f3c11 in handle_internal_command (argc=5,
argv=0x7fffffffe468) at perf.c:365
#8  0x00005555562f3fce in run_argv (argcp=0x7fffffffe240,
argv=0x7fffffffe250) at perf.c:409
#9  0x00005555562f47bd in main (argc=5, argv=0x7fffffffe468) at perf.c:539

And then overwritten causing the leak:
#0  0x00005555563b965a in process_cpuid (ff=0x7fffffffad50, data=0x0)
at util/header.c:2333
#1  0x00005555563c53d2 in perf_event__process_feature
(session=0x62b000007200, event=0x621000006500) at util/header.c:4144
#2  0x000055555615fdef in process_feature_event
(session=0x62b000007200, event=0x621000006500) at builtin-report.c:230
#3  0x00005555563fa033 in perf_session__process_user_event
(session=0x62b000007200, event=0x621000006500, file_offset=868)
    at util/session.c:1668
#4  0x00005555563fae08 in perf_session__process_event
(session=0x62b000007200, event=0x621000006500, file_offset=868)
    at util/session.c:1803
#5  0x00005555563fc4e6 in __perf_session__process_pipe_events
(session=0x62b000007200) at util/session.c:2044
#6  0x00005555563ff005 in perf_session__process_events
(session=0x62b000007200) at util/session.c:2418
#7  0x000055555616508a in __cmd_report (rep=0x7fffffffbaa0) at
builtin-report.c:940
#8  0x000055555616f5c9 in cmd_report (argc=0, argv=0x7fffffffe468) at
builtin-report.c:1629
#9  0x00005555562f36b8 in run_builtin (p=0x5555586bacd0
<commands+240>, argc=5, argv=0x7fffffffe468) at perf.c:313
#10 0x00005555562f3c11 in handle_internal_command (argc=5,
argv=0x7fffffffe468) at perf.c:365
#11 0x00005555562f3fce in run_argv (argcp=0x7fffffffe240,
argv=0x7fffffffe250) at perf.c:409
#12 0x00005555562f47bd in main (argc=5, argv=0x7fffffffe468) at perf.c:539

Thanks,
Ian

jirka

quoted

      ff->ph->env.__feat_env = do_read_string(ff); \
      return ff->ph->env.__feat_env ? 0 : -ENOMEM; \
 }

@@ -4124,6 +4125,7 @@ int perf_event__process_feature(struct perf_session *session,
      struct perf_record_header_feature *fe = (struct perf_record_header_feature *)event;
      int type = fe->header.type;
      u64 feat = fe->feat_id;
+     int ret = 0;

      if (type < 0 || type >= PERF_RECORD_HEADER_MAX) {
              pr_warning("invalid record type %d in pipe-mode\n", type);

@@ -4141,11 +4143,13 @@ int perf_event__process_feature(struct perf_session *session,
      ff.size = event->header.size - sizeof(*fe);
      ff.ph = &session->header;

-     if (feat_ops[feat].process(&ff, NULL))
-             return -1;
+     if (feat_ops[feat].process(&ff, NULL)) {
+             ret = -1;
+             goto out;
+     }

      if (!feat_ops[feat].print || !tool->show_feat_hdr)
-             return 0;
+             goto out;

      if (!feat_ops[feat].full_only ||
          tool->show_feat_hdr >= SHOW_FEAT_HEADER_FULL_INFO) {

@@ -4154,8 +4158,9 @@ int perf_event__process_feature(struct perf_session *session,
              fprintf(stdout, "# %s info available, use -I to display\n",
                      feat_ops[feat].name);
      }
-
-     return 0;
+out:
+     free_event_desc(ff.events);
+     return ret;
 }

 size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp)
--

2.34.0.rc2.393.gf8c9666880-goog