[PATCH v1 3/5] perf trace-event: Free the global trace_event when a command ends

[Ian Rogers]

The tep handle behind trace_event__tp_format() is a process wide cache
of the running kernel's tracepoint formats and nothing ever released
it, as the comment above it had noted since the code was added.

Add trace_event__exit() and call it from run_builtin() next to the
existing perf_config__exit(). By then the builtin has returned, so the
tep_event pointers it handed out, such as the ones cached in
evsel->tp_format, are no longer reachable.

Note that this does not silence every libtraceevent report under
leak sanitizer. Parsing a print fmt drops a token inside the library
itself, and as those allocations are not linked into the handle,
freeing the handle cannot reclaim them.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/perf.c             |  6 ++++++
 tools/perf/util/trace-event.c | 22 +++++++++++++++++-----
 tools/perf/util/trace-event.h |  1 +
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 6c5baa285b13..d60bc929c257 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -32,6 +32,9 @@
 #include "util/build-id.h"
 #include "util/config.h"
 #include "util/debug.h"
+#ifdef HAVE_LIBTRACEEVENT
+#include "util/trace-event.h"
+#endif
 
 const char perf_usage_string[] =
 	"perf [--version] [--help] [OPTIONS] COMMAND [ARGS]";
@@ -379,6 +382,9 @@ static int run_builtin(const struct cmd_struct *p, int argc, const char **argv)
 
 	status = p->fn(argc, argv);
 	perf_config__exit();
+#ifdef HAVE_LIBTRACEEVENT
+	trace_event__exit();
+#endif
 	exit_browser(status);
 
 	if (status)
diff --git a/tools/perf/util/trace-event.c b/tools/perf/util/trace-event.c
index 826f75464171..819542a73f55 100644
--- a/tools/perf/util/trace-event.c
+++ b/tools/perf/util/trace-event.c
@@ -14,11 +14,9 @@
 #include "machine.h"
 
 /*
- * global trace_event object used by trace_event__tp_format
- *
- * TODO There's no cleanup call for this. Add some sort of
- * __exit function support and call trace_event__cleanup
- * there.
+ * Global trace_event object used by trace_event__tp_format. It caches the
+ * tracepoint formats of the running kernel for the lifetime of the command
+ * and is released by trace_event__exit.
  */
 static struct trace_event tevent;
 static bool tevent_initialized;
@@ -75,6 +73,20 @@ void trace_event__cleanup(struct trace_event *t)
 	t->plugin_list = NULL;
 }
 
+/*
+ * Release the global trace_event. Called once the command is done, when the
+ * tep_event pointers handed out by trace_event__tp_format are no longer in
+ * use.
+ */
+void trace_event__exit(void)
+{
+	if (!tevent_initialized)
+		return;
+
+	trace_event__cleanup(&tevent);
+	tevent_initialized = false;
+}
+
 /*
  * Returns NULL and sets errno on failure.
  */
diff --git a/tools/perf/util/trace-event.h b/tools/perf/util/trace-event.h
index 720121c74f1d..1c342fce36bb 100644
--- a/tools/perf/util/trace-event.h
+++ b/tools/perf/util/trace-event.h
@@ -32,6 +32,7 @@ bool have_tracepoints(struct list_head *evlist);
 
 int trace_event__init(struct trace_event *t);
 void trace_event__cleanup(struct trace_event *t);
+void trace_event__exit(void);
 int trace_event__register_resolver(struct machine *machine,
 				   tep_func_resolver_t *func);
 struct tep_event*
-- 
2.55.0.1082.g2b9226bbc0-goog