[PATCH v2 5/6] tracing: uprobe-event: Allocate string buffers from heap

Masami Hiramatsu (Google)
2025-07-20T06:22:30Z

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

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Sort #include alphabetically.
- Add fail_mem label for handling ENOMEM error.
---
kernel/trace/trace_uprobe.c | 40 +++++++++++++++++++++++++---------------
1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 797ac1250956..8b0bcc0d8f41 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -8,17 +8,19 @@
#define pr_fmt(fmt) "trace_uprobe: " fmt

#include <linux/bpf-cgroup.h>
-#include <linux/security.h>
+#include <linux/cleanup.h>
#include <linux/ctype.h>
+#include <linux/filter.h>
#include <linux/module.h>
-#include <linux/uaccess.h>
-#include <linux/uprobes.h>
#include <linux/namei.h>
-#include <linux/string.h>
-#include <linux/rculist.h>
-#include <linux/filter.h>
#include <linux/percpu.h>
+#include <linux/rculist.h>
+#include <linux/security.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/uprobes.h>

+#include "trace.h"
#include "trace_dynevent.h"
#include "trace_probe.h"
#include "trace_probe_tmpl.h"
@@ -537,15 +539,15 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
*/
static int __trace_uprobe_create(int argc, const char **argv)
{
- struct trace_uprobe *tu;
const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
char *arg, *filename, *rctr, *rctr_end, *tmp;
- char buf[MAX_EVENT_NAME_LEN];
- char gbuf[MAX_EVENT_NAME_LEN];
- enum probe_print_type ptype;
- struct path path;
unsigned long offset, ref_ctr_offset;
+ char *gbuf __free(kfree) = NULL;
+ char *buf __free(kfree) = NULL;
+ enum probe_print_type ptype;
+ struct trace_uprobe *tu;
bool is_return = false;
+ struct path path;
int i, ret;

ref_ctr_offset = 0;
@@ -653,6 +655,10 @@ static int __trace_uprobe_create(int argc, const char **argv)
/* setup a probe */
trace_probe_log_set_index(0);
if (event) {
+ gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+ if (!gbuf)
+ goto fail_mem;
+
ret = traceprobe_parse_event_name(&event, &group, gbuf,
event - argv[0]);
if (ret)
@@ -664,15 +670,16 @@ static int __trace_uprobe_create(int argc, const char **argv)
char *ptr;

tail = kstrdup(kbasename(filename), GFP_KERNEL);
- if (!tail) {
- ret = -ENOMEM;
- goto fail_address_parse;
- }
+ if (!tail)
+ goto fail_mem;

ptr = strpbrk(tail, ".-_");
if (ptr)
*ptr = '\0';

+ buf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+ if (!buf)
+ goto fail_mem;
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
event = buf;
kfree(tail);
@@ -724,6 +731,9 @@ static int __trace_uprobe_create(int argc, const char **argv)
trace_probe_log_clear();
return ret;

+fail_mem:
+ ret = -ENOMEM;
+
fail_address_parse:
trace_probe_log_clear();
path_put(&path);