[PATCH 4/5] tracing: eprobe-event: Allocate string buffers from heap

Masami Hiramatsu (Google)
2025-07-18T11:34:45Z

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Allocate temporary string buffers for parsing eprobe-events
from heap instead of stack.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
kernel/trace/trace_eprobe.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 1e18a8619b40..75d8208cd859 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -9,6 +9,7 @@
* Copyright (C) 2021, VMware Inc, Tzvetomir Stoyanov tz.stoyanov@gmail.com>
*
*/
+#include <linux/cleanup.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>
@@ -871,10 +872,10 @@ static int __trace_eprobe_create(int argc, const char *argv[])
const char *event = NULL, *group = EPROBE_EVENT_SYSTEM;
const char *sys_event = NULL, *sys_name = NULL;
struct trace_event_call *event_call;
+ char *buf1 __free(kfree) = NULL;
+ char *buf2 __free(kfree) = NULL;
+ char *gbuf __free(kfree) = NULL;
struct trace_eprobe *ep = NULL;
- char buf1[MAX_EVENT_NAME_LEN];
- char buf2[MAX_EVENT_NAME_LEN];
- char gbuf[MAX_EVENT_NAME_LEN];
int ret = 0, filter_idx = 0;
int i, filter_cnt;

@@ -885,6 +886,11 @@ static int __trace_eprobe_create(int argc, const char *argv[])

event = strchr(&argv[0][1], ':');
if (event) {
+ gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+ if (!gbuf) {
+ ret = -ENOMEM;
+ goto parse_error;
+ }
event++;
ret = traceprobe_parse_event_name(&event, &group, gbuf,
event - argv[0]);
@@ -894,6 +900,12 @@ static int __trace_eprobe_create(int argc, const char *argv[])

trace_probe_log_set_index(1);
sys_event = argv[1];
+
+ buf2 = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+ if (!buf2) {
+ ret = -ENOMEM;
+ goto parse_error;
+ }
ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0);
if (ret || !sys_event || !sys_name) {
trace_probe_log_err(0, NO_EVENT_INFO);
@@ -901,7 +913,11 @@ static int __trace_eprobe_create(int argc, const char *argv[])
}

if (!event) {
- strscpy(buf1, sys_event, MAX_EVENT_NAME_LEN);
+ buf1 = kstrdup(sys_event, GFP_KERNEL);
+ if (!buf1) {
+ ret = -ENOMEM;
+ goto error;
+ }
event = buf1;
}