[PATCH v2 03/16] perf tools: Fix sb_evlist leaks in top and record

[Ian Rogers]

Fix a memory leak in cmd_top() where top.sb_evlist was not freed if
evlist__add_bpf_sb_event() fails. Note that evlist__start_sb_thread() and
evlist__stop_sb_thread() take ownership of the evlist and free it, so
we must only free it if we fail before starting the thread. Also set
top.sb_evlist to NULL to prevent use-after-free bugs.

Apply the same fix to builtin-record.c to avoid leaking rec->sb_evlist
and calling pthread_join on uninitialized threads in the error path.

Assisted-by: Antigravity:gemini-3.1-pro
Fixes: b38d85ef49cf ("perf bpf: Decouple creating the evlist from adding the SB event")
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/builtin-record.c | 2 ++
 tools/perf/builtin-top.c    | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index ebd3ed0c9b3e..b106d50f6d97 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -2247,6 +2247,8 @@ static int record__setup_sb_evlist(struct record *rec)
 
 		if (evlist__add_bpf_sb_event(rec->sb_evlist, perf_session__env(rec->session))) {
 			pr_err("Couldn't ask for PERF_RECORD_BPF_EVENT side band events.\n.");
+			evlist__put(rec->sb_evlist);
+			rec->sb_evlist = NULL;
 			return -1;
 		}
 	}
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 5933c46ee137..570410599f1b 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1881,6 +1881,8 @@ int cmd_top(int argc, const char **argv)
 		if (evlist__add_bpf_sb_event(top.sb_evlist, &host_env)) {
 			pr_err("Couldn't ask for PERF_RECORD_BPF_EVENT side band events.\n.");
 			status = -EINVAL;
+			evlist__put(top.sb_evlist);
+			top.sb_evlist = NULL;
 			goto out_put_evlist;
 		}
 	}
-- 
2.55.0.rc0.799.gd6f94ed593-goog