[PATCH v1 1/3] perf: Dynamically allocate buffer for event string

From: Leo Yan
Date: Mon Oct 07 2024 - 10:12:43 EST


Dynamically allocate and free buffer to support event name.

Signed-off-by: Leo Yan <leo.yan@xxxxxxx>
---
tools/perf/util/probe-event.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a17c9b8a7a79..cad11d95af4f 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2834,6 +2834,9 @@ static void warn_uprobe_event_compat(struct probe_trace_event *tev)
free(buf);
}

+/* Defined in kernel/trace/trace.h */
+#define MAX_EVENT_NAME_LEN 64
+
/* Set new name from original perf_probe_event and namelist */
static int probe_trace_event__set_name(struct probe_trace_event *tev,
struct perf_probe_event *pev,
@@ -2841,9 +2844,13 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
bool allow_suffix)
{
const char *event, *group;
- char buf[64];
+ char *buf;
int ret;

+ buf = malloc(MAX_EVENT_NAME_LEN);
+ if (!buf)
+ return -ENOMEM;
+
/* If probe_event or trace_event already have the name, reuse it */
if (pev->event && !pev->sdt)
event = pev->event;
@@ -2866,17 +2873,19 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
group = PERFPROBE_GROUP;

/* Get an unused new event name */
- ret = get_new_event_name(buf, sizeof(buf), event, namelist,
+ ret = get_new_event_name(buf, MAX_EVENT_NAME_LEN, event, namelist,
tev->point.retprobe, allow_suffix);
if (ret < 0)
- return ret;
+ goto out;

event = buf;

tev->event = strdup(event);
tev->group = strdup(group);
- if (tev->event == NULL || tev->group == NULL)
- return -ENOMEM;
+ if (tev->event == NULL || tev->group == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }

/*
* Add new event name to namelist if multiprobe event is NOT
@@ -2885,7 +2894,10 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
*/
if (!multiprobe_event_is_supported())
strlist__add(namelist, event);
- return 0;
+
+out:
+ free(buf);
+ return ret < 0 ? ret : 0;
}

static int __open_probe_file_and_namelist(bool uprobe,
--
2.34.1