[PATCH v2 4/6] tracing: eprobe-event: Allocate string buffers from heap

Masami Hiramatsu (Google)
2025-07-20T06:22:20Z

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

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Use new label for returning -ENOMEM.
- Sort #include alphabetically.
---
kernel/trace/trace_eprobe.c | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 1e18a8619b40..f16a0ab0b001 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -9,14 +9,15 @@
* Copyright (C) 2021, VMware Inc, Tzvetomir Stoyanov tz.stoyanov@gmail.com>
*
*/
+#include <linux/cleanup.h>
+#include <linux/ftrace.h>
#include <linux/module.h>
#include <linux/mutex.h>
-#include <linux/ftrace.h>

#include "trace_dynevent.h"
#include "trace_probe.h"
-#include "trace_probe_tmpl.h"
#include "trace_probe_kernel.h"
+#include "trace_probe_tmpl.h"

#define EPROBE_EVENT_SYSTEM "eprobes"

@@ -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 +886,9 @@ 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)
+ goto mem_error;
event++;
ret = traceprobe_parse_event_name(&event, &group, gbuf,
event - argv[0]);
@@ -894,6 +898,11 @@ 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)
+ goto mem_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 +910,9 @@ 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)
+ goto mem_error;
event = buf1;
}

@@ -974,6 +985,9 @@ static int __trace_eprobe_create(int argc, const char *argv[])
trace_probe_log_clear();
return ret;

+mem_error:
+ ret = -ENOMEM;
+ goto error;
parse_error:
ret = -EINVAL;