[PATCH v2 0/6] tracing: probes: Use heap instead of stack for temporary buffers

[PATCH v2 0/6] tracing: probes: Use heap instead of stack for temporary buffers

[Masami Hiramatsu (Google)]

Hi,

This is the 2nd version of the series of cleanup patches which allocate
temporary buffers and objects on heap (slab) instead of the stack.
The previous version is here;

https://lore.kernel.org/all/175283843771.343578.8524137568048302760.stgit@devnote2/

This version updated patches according to the comment, also sorts the
#include alphabetically. Also add a kerneldoc for
traceprobe_parse_event_name().

---

Masami Hiramatsu (Google) (6):
      tracing: probe: Allocate traceprobe_parse_context from heap
      tracing: fprobe-event: Allocate string buffers from heap
      tracing: kprobe-event: Allocate string buffers from heap
      tracing: eprobe-event: Allocate string buffers from heap
      tracing: uprobe-event: Allocate string buffers from heap
      tracing: probes: Add a kerneldoc for traceprobe_parse_event_name()


 kernel/trace/trace_eprobe.c |   40 +++++++++++++++++++++++---------
 kernel/trace/trace_fprobe.c |   52 ++++++++++++++++++++++++++++--------------
 kernel/trace/trace_kprobe.c |   49 ++++++++++++++++++++++++++--------------
 kernel/trace/trace_probe.c  |   17 +++++++++++++-
 kernel/trace/trace_probe.h  |   26 +++++++++++++++------
 kernel/trace/trace_uprobe.c |   53 +++++++++++++++++++++++++++----------------
 6 files changed, 161 insertions(+), 76 deletions(-)

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

[PATCH v2 1/6] tracing: probe: Allocate traceprobe_parse_context from heap

[Masami Hiramatsu (Google)]

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

Instead of allocating traceprobe_parse_context on stack, allocate it
dynamically from heap (slab).

This change is likely intended to prevent potential stack overflow
issues, which can be a concern in the kernel environment where stack
space is limited.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506240416.nZIhDXoO-lkp@intel.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 Changes in v2:
  - Sort #include alphabetically.
  - Just NULL check for freeing traceprobe_parse_context.
  - Do not change the semantics of traceprobe_parse_context for uprobe
    event. (alloc/free in loop)
---
 kernel/trace/trace_eprobe.c |   14 ++++++++------
 kernel/trace/trace_fprobe.c |   13 ++++++++-----
 kernel/trace/trace_kprobe.c |   10 +++++++---
 kernel/trace/trace_probe.h  |   26 ++++++++++++++++++--------
 kernel/trace/trace_uprobe.c |   13 ++++++++-----
 5 files changed, 49 insertions(+), 27 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 916555f0de81..1e18a8619b40 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -797,18 +797,20 @@ find_and_get_event(const char *system, const char *event_name)
 
 static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i)
 {
-	struct traceprobe_parse_context ctx = {
-		.event = ep->event,
-		.flags = TPARG_FL_KERNEL | TPARG_FL_TEVENT,
-	};
+	struct traceprobe_parse_context *ctx __free(traceprobe_parse_context) = NULL;
 	int ret;
 
-	ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], &ctx);
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	ctx->event = ep->event;
+	ctx->flags = TPARG_FL_KERNEL | TPARG_FL_TEVENT;
+
+	ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], ctx);
 	/* Handle symbols "@" */
 	if (!ret)
 		ret = traceprobe_update_arg(&ep->tp.args[i]);
 
-	traceprobe_finish_parse(&ctx);
 	return ret;
 }
 
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index dbf9d413125a..264cf7fc9a1d 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -1383,14 +1383,17 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 
 static int trace_fprobe_create_cb(int argc, const char *argv[])
 {
-	struct traceprobe_parse_context ctx = {
-		.flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE,
-	};
+	struct traceprobe_parse_context *ctx __free(traceprobe_parse_context) = NULL;
 	int ret;
 
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE,
+
 	trace_probe_log_init("trace_fprobe", argc, argv);
-	ret = trace_fprobe_create_internal(argc, argv, &ctx);
-	traceprobe_finish_parse(&ctx);
+	ret = trace_fprobe_create_internal(argc, argv, ctx);
 	trace_probe_log_clear();
 	return ret;
 }
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 3e5c47b6d7b2..15d7a381a128 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1065,14 +1065,18 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 
 static int trace_kprobe_create_cb(int argc, const char *argv[])
 {
-	struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
+	struct traceprobe_parse_context *ctx __free(traceprobe_parse_context) = NULL;
 	int ret;
 
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	ctx->flags = TPARG_FL_KERNEL;
+
 	trace_probe_log_init("trace_kprobe", argc, argv);
 
-	ret = trace_kprobe_create_internal(argc, argv, &ctx);
+	ret = trace_kprobe_create_internal(argc, argv, ctx);
 
-	traceprobe_finish_parse(&ctx);
 	trace_probe_log_clear();
 	return ret;
 }
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 854e5668f5ee..842383fbc03b 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -10,20 +10,22 @@
  * Author:     Srikar Dronamraju
  */
 
+#include <linux/bitops.h>
+#include <linux/btf.h>
+#include <linux/cleanup.h>
+#include <linux/kprobes.h>
+#include <linux/limits.h>
+#include <linux/perf_event.h>
+#include <linux/ptrace.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/smp.h>
-#include <linux/tracefs.h>
-#include <linux/types.h>
 #include <linux/string.h>
-#include <linux/ptrace.h>
-#include <linux/perf_event.h>
-#include <linux/kprobes.h>
 #include <linux/stringify.h>
-#include <linux/limits.h>
+#include <linux/tracefs.h>
+#include <linux/types.h>
 #include <linux/uaccess.h>
-#include <linux/bitops.h>
-#include <linux/btf.h>
+
 #include <asm/bitsperlong.h>
 
 #include "trace.h"
@@ -438,6 +440,14 @@ extern void traceprobe_free_probe_arg(struct probe_arg *arg);
  * this MUST be called for clean up the context and return a resource.
  */
 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx);
+static inline void traceprobe_free_parse_ctx(struct traceprobe_parse_context *ctx)
+{
+	traceprobe_finish_parse(ctx);
+	kfree(ctx);
+}
+
+DEFINE_FREE(traceprobe_parse_context, struct traceprobe_parse_context *,
+	if (_T) traceprobe_free_parse_ctx(_T))
 
 extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index f95a2c3d5b1b..797ac1250956 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -695,13 +695,16 @@ static int __trace_uprobe_create(int argc, const char **argv)
 
 	/* parse arguments */
 	for (i = 0; i < argc; i++) {
-		struct traceprobe_parse_context ctx = {
-			.flags = (is_return ? TPARG_FL_RETURN : 0) | TPARG_FL_USER,
-		};
+		struct traceprobe_parse_context *ctx __free(traceprobe_parse_context)
+			= kzalloc(sizeof(*ctx), GFP_KERNEL);
 
+		if (!ctx) {
+			ret = -ENOMEM;
+			goto error;
+		}
+		ctx->flags = (is_return ? TPARG_FL_RETURN : 0) | TPARG_FL_USER;
 		trace_probe_log_set_index(i + 2);
-		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i], &ctx);
-		traceprobe_finish_parse(&ctx);
+		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i], ctx);
 		if (ret)
 			goto error;
 	}

Re: [PATCH v2 1/6] tracing: probe: Allocate traceprobe_parse_context from heap

[Steven Rostedt]

On Sun, 20 Jul 2025 15:21:47 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

>  
> +#include <linux/bitops.h>
> +#include <linux/btf.h>
> +#include <linux/cleanup.h>
> +#include <linux/kprobes.h>
> +#include <linux/limits.h>
> +#include <linux/perf_event.h>
> +#include <linux/ptrace.h>
>  #include <linux/seq_file.h>
>  #include <linux/slab.h>
>  #include <linux/smp.h>
> -#include <linux/tracefs.h>
> -#include <linux/types.h>
>  #include <linux/string.h>
> -#include <linux/ptrace.h>
> -#include <linux/perf_event.h>
> -#include <linux/kprobes.h>
>  #include <linux/stringify.h>
> -#include <linux/limits.h>
> +#include <linux/tracefs.h>
> +#include <linux/types.h>
>  #include <linux/uaccess.h>
> -#include <linux/bitops.h>
> -#include <linux/btf.h>
> +

A re-sort should be a separate patch, as I can't tell what changed in
the header for this patch.

-- Steve

Re: [PATCH v2 1/6] tracing: probe: Allocate traceprobe_parse_context from heap

[Masami Hiramatsu]

On Mon, 21 Jul 2025 13:19:07 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Sun, 20 Jul 2025 15:21:47 +0900
> "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
> 
> >  
> > +#include <linux/bitops.h>
> > +#include <linux/btf.h>
> > +#include <linux/cleanup.h>
> > +#include <linux/kprobes.h>
> > +#include <linux/limits.h>
> > +#include <linux/perf_event.h>
> > +#include <linux/ptrace.h>
> >  #include <linux/seq_file.h>
> >  #include <linux/slab.h>
> >  #include <linux/smp.h>
> > -#include <linux/tracefs.h>
> > -#include <linux/types.h>
> >  #include <linux/string.h>
> > -#include <linux/ptrace.h>
> > -#include <linux/perf_event.h>
> > -#include <linux/kprobes.h>
> >  #include <linux/stringify.h>
> > -#include <linux/limits.h>
> > +#include <linux/tracefs.h>
> > +#include <linux/types.h>
> >  #include <linux/uaccess.h>
> > -#include <linux/bitops.h>
> > -#include <linux/btf.h>
> > +
> 
> A re-sort should be a separate patch, as I can't tell what changed in
> the header for this patch.

OK, let me make it a separate patch.

Thanks!

> 
> -- Steve


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

[PATCH v2 2/6] tracing: fprobe-event: Allocate string buffers from heap

[Masami Hiramatsu (Google)]

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

Allocate temporary string buffers for fprobe-event from heap
instead of stack. This fixes the stack frame exceed limit error.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506240416.nZIhDXoO-lkp@intel.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 kernel/trace/trace_fprobe.c |   39 ++++++++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 264cf7fc9a1d..fd1036e27309 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -1234,18 +1234,18 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 	 */
 	struct trace_fprobe *tf __free(free_trace_fprobe) = NULL;
-	struct module *mod __free(module_put) = NULL;
-	int i, new_argc = 0, ret = 0;
-	bool is_return = false;
-	char *symbol __free(kfree) = NULL;
 	const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
+	struct module *mod __free(module_put) = NULL;
 	const char **new_argv __free(kfree) = NULL;
-	char buf[MAX_EVENT_NAME_LEN];
-	char gbuf[MAX_EVENT_NAME_LEN];
-	char sbuf[KSYM_NAME_LEN];
-	char abuf[MAX_BTF_ARGS_LEN];
+	char *symbol __free(kfree) = NULL;
+	char *ebuf __free(kfree) = NULL;
+	char *gbuf __free(kfree) = NULL;
+	char *sbuf __free(kfree) = NULL;
+	char *abuf __free(kfree) = NULL;
 	char *dbuf __free(kfree) = NULL;
+	int i, new_argc = 0, ret = 0;
 	bool is_tracepoint = false;
+	bool is_return = false;
 
 	if ((argv[0][0] != 'f' && argv[0][0] != 't') || argc < 2)
 		return -ECANCELED;
@@ -1273,6 +1273,9 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 
 	trace_probe_log_set_index(0);
 	if (event) {
+		gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+		if (!gbuf)
+			return -ENOMEM;
 		ret = traceprobe_parse_event_name(&event, &group, gbuf,
 						  event - argv[0]);
 		if (ret)
@@ -1280,15 +1283,18 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 	}
 
 	if (!event) {
+		ebuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+		if (!ebuf)
+			return -ENOMEM;
 		/* Make a new event name */
 		if (is_tracepoint)
-			snprintf(buf, MAX_EVENT_NAME_LEN, "%s%s",
+			snprintf(ebuf, MAX_EVENT_NAME_LEN, "%s%s",
 				 isdigit(*symbol) ? "_" : "", symbol);
 		else
-			snprintf(buf, MAX_EVENT_NAME_LEN, "%s__%s", symbol,
+			snprintf(ebuf, MAX_EVENT_NAME_LEN, "%s__%s", symbol,
 				 is_return ? "exit" : "entry");
-		sanitize_event_name(buf);
-		event = buf;
+		sanitize_event_name(ebuf);
+		event = ebuf;
 	}
 
 	if (is_return)
@@ -1304,13 +1310,20 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 		ctx->flags |= TPARG_FL_TPOINT;
 		mod = NULL;
 		tpoint = find_tracepoint(symbol, &mod);
-		if (tpoint)
+		if (tpoint) {
+			sbuf = kmalloc(KSYM_NAME_LEN, GFP_KERNEL);
+			if (!sbuf)
+				return -ENOMEM;
 			ctx->funcname = kallsyms_lookup((unsigned long)tpoint->probestub,
 							NULL, NULL, NULL, sbuf);
+		}
 	}
 	if (!ctx->funcname)
 		ctx->funcname = symbol;
 
+	abuf = kmalloc(MAX_BTF_ARGS_LEN, GFP_KERNEL);
+	if (!abuf)
+		return -ENOMEM;
 	argc -= 2; argv += 2;
 	new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
 					       abuf, MAX_BTF_ARGS_LEN, ctx);

[PATCH v2 3/6] tracing: kprobe-event: Allocate string buffers from heap

[Masami Hiramatsu (Google)]

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

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

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |   39 +++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 14 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 15d7a381a128..793af6000f16 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -861,20 +861,20 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 	 */
 	struct trace_kprobe *tk __free(free_trace_kprobe) = NULL;
+	const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
+	const char **new_argv __free(kfree) = NULL;
 	int i, len, new_argc = 0, ret = 0;
-	bool is_return = false;
 	char *symbol __free(kfree) = NULL;
-	char *tmp = NULL;
-	const char **new_argv __free(kfree) = NULL;
-	const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
+	char *ebuf __free(kfree) = NULL;
+	char *gbuf __free(kfree) = NULL;
+	char *abuf __free(kfree) = NULL;
+	char *dbuf __free(kfree) = NULL;
 	enum probe_print_type ptype;
+	bool is_return = false;
 	int maxactive = 0;
-	long offset = 0;
 	void *addr = NULL;
-	char buf[MAX_EVENT_NAME_LEN];
-	char gbuf[MAX_EVENT_NAME_LEN];
-	char abuf[MAX_BTF_ARGS_LEN];
-	char *dbuf __free(kfree) = NULL;
+	char *tmp = NULL;
+	long offset = 0;
 
 	switch (argv[0][0]) {
 	case 'r':
@@ -893,6 +893,8 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 		event++;
 
 	if (isdigit(argv[0][1])) {
+		char *buf __free(kfree) = NULL;
+
 		if (!is_return) {
 			trace_probe_log_err(1, BAD_MAXACT_TYPE);
 			return -EINVAL;
@@ -905,7 +907,7 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 			trace_probe_log_err(1, BAD_MAXACT);
 			return -EINVAL;
 		}
-		memcpy(buf, &argv[0][1], len);
+		buf = kmemdup(&argv[0][1], len + 1, GFP_KERNEL);
 		buf[len] = '\0';
 		ret = kstrtouint(buf, 0, &maxactive);
 		if (ret || !maxactive) {
@@ -973,6 +975,9 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 
 	trace_probe_log_set_index(0);
 	if (event) {
+		gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+		if (!gbuf)
+			return -ENOMEM;
 		ret = traceprobe_parse_event_name(&event, &group, gbuf,
 						  event - argv[0]);
 		if (ret)
@@ -981,16 +986,22 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 
 	if (!event) {
 		/* Make a new event name */
+		ebuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+		if (!ebuf)
+			return -ENOMEM;
 		if (symbol)
-			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
+			snprintf(ebuf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 				 is_return ? 'r' : 'p', symbol, offset);
 		else
-			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
+			snprintf(ebuf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 				 is_return ? 'r' : 'p', addr);
-		sanitize_event_name(buf);
-		event = buf;
+		sanitize_event_name(ebuf);
+		event = ebuf;
 	}
 
+	abuf = kmalloc(MAX_BTF_ARGS_LEN, GFP_KERNEL);
+	if (!abuf)
+		return -ENOMEM;
 	argc -= 2; argv += 2;
 	ctx->funcname = symbol;
 	new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,

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

[Masami Hiramatsu (Google)]

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>
---
 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;
 error:

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

[Steven Rostedt]

On Sun, 20 Jul 2025 15:22:16 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> 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>

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

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

[Masami Hiramatsu (Google)]

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

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);

[PATCH v2 6/6] tracing: probes: Add a kerneldoc for traceprobe_parse_event_name()

[Masami Hiramatsu (Google)]

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

Since traceprobe_parse_event_name() is a bit complicated, add a
kerneldoc for explaining the behavior.

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 kernel/trace/trace_probe.c |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index abfab8957a6c..72bf430a3804 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -247,7 +247,22 @@ int traceprobe_split_symbol_offset(char *symbol, long *offset)
 	return 0;
 }
 
-/* @buf must has MAX_EVENT_NAME_LEN size */
+/**
+ * traceprobe_parse_event_name - Parse a string into group and event names
+ * @pevent: A pointer to the string to be parsed. On return, this is updated
+ *          to point to the event name part of the string.
+ * @pgroup: A pointer to the group name. This is updated to point to the parsed
+ *          group name, which is stored in @buf.
+ * @buf:    A buffer to store the parsed group name.
+ * @offset: The offset of the string in the original user command, for logging.
+ *
+ * Description: This parses a string with the format `[GROUP/][EVENT]` or
+ *          `[GROUP.][EVENT]` (either GROUP or EVENT or both must be specified).
+ *          The parsed group name is stored in @buf.
+ *          The caller must ensure @buf is at least MAX_EVENT_NAME_LEN bytes.
+ *
+ * Return: 0 on success, or -EINVAL on failure.
+ */
 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 				char *buf, int offset)
 {