linux-kernel - [rtla 01/13] rtla: Check for memory allocation failures

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Message-ID: <20251117184409.42831-2-wander@redhat.com>
Date: Mon, 17 Nov 2025 15:41:08 -0300
From: Wander Lairson Costa <wander@...hat.com>
To: Steven Rostedt <rostedt@...dmis.org>,
	Wander Lairson Costa <wander@...hat.com>,
	Tomas Glozar <tglozar@...hat.com>,
	Ivan Pravdin <ipravdin.official@...il.com>,
	Crystal Wood <crwood@...hat.com>,
	John Kacur <jkacur@...hat.com>,
	Costa Shulyupin <costa.shul@...hat.com>,
	Tiezhu Yang <yangtiezhu@...ngson.cn>,
	linux-trace-kernel@...r.kernel.org (open list:Real-time Linux Analysis (RTLA) tools),
	linux-kernel@...r.kernel.org (open list),
	bpf@...r.kernel.org (open list:BPF [MISC]:Keyword:(?:\b|_)bpf(?:\b|_))
Subject: [rtla 01/13] rtla: Check for memory allocation failures

The actions_init() and actions_new() functions did not check the
return value of calloc() and realloc() respectively. In a low
memory situation, this could lead to a NULL pointer dereference.

Add checks for the return value of memory allocation functions
and return an error in case of failure. Update the callers to
handle the error properly.

Signed-off-by: Wander Lairson Costa <wander@...hat.com>
---
 tools/tracing/rtla/src/actions.c       | 26 +++++++++++++++++++++++---
 tools/tracing/rtla/src/actions.h       |  2 +-
 tools/tracing/rtla/src/timerlat_hist.c |  7 +++++--
 tools/tracing/rtla/src/timerlat_top.c  |  7 +++++--
 4 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/tools/tracing/rtla/src/actions.c b/tools/tracing/rtla/src/actions.c
index 8945aee58d511..01648a1425c10 100644
--- a/tools/tracing/rtla/src/actions.c
+++ b/tools/tracing/rtla/src/actions.c
@@ -11,11 +11,13 @@
 /*
  * actions_init - initialize struct actions
  */
-void
+int
 actions_init(struct actions *self)
 {
 	self->size = action_default_size;
 	self->list = calloc(self->size, sizeof(struct action));
+	if (!self->list)
+		return -1;
 	self->len = 0;
 	self->continue_flag = false;
 
@@ -23,6 +25,7 @@ actions_init(struct actions *self)
 
 	/* This has to be set by the user */
 	self->trace_output_inst = NULL;
+	return 0;
 }
 
 /*
@@ -50,8 +53,13 @@ static struct action *
 actions_new(struct actions *self)
 {
 	if (self->len >= self->size) {
-		self->size *= 2;
-		self->list = realloc(self->list, self->size * sizeof(struct action));
+		const size_t new_size = self->size * 2;
+		void *p = reallocarray(self->list, new_size, sizeof(struct action));
+
+		if (!p)
+			return NULL;
+		self->list = p;
+		self->size = new_size;
 	}
 
 	return &self->list[self->len++];
@@ -65,6 +73,9 @@ actions_add_trace_output(struct actions *self, const char *trace_output)
 {
 	struct action *action = actions_new(self);
 
+	if (!action)
+		return -1;
+
 	self->present[ACTION_TRACE_OUTPUT] = true;
 	action->type = ACTION_TRACE_OUTPUT;
 	action->trace_output = calloc(strlen(trace_output) + 1, sizeof(char));
@@ -83,6 +94,9 @@ actions_add_signal(struct actions *self, int signal, int pid)
 {
 	struct action *action = actions_new(self);
 
+	if (!action)
+		return -1;
+
 	self->present[ACTION_SIGNAL] = true;
 	action->type = ACTION_SIGNAL;
 	action->signal = signal;
@@ -99,6 +113,9 @@ actions_add_shell(struct actions *self, const char *command)
 {
 	struct action *action = actions_new(self);
 
+	if (!action)
+		return -1;
+
 	self->present[ACTION_SHELL] = true;
 	action->type = ACTION_SHELL;
 	action->command = calloc(strlen(command) + 1, sizeof(char));
@@ -117,6 +134,9 @@ actions_add_continue(struct actions *self)
 {
 	struct action *action = actions_new(self);
 
+	if (!action)
+		return -1;
+
 	self->present[ACTION_CONTINUE] = true;
 	action->type = ACTION_CONTINUE;
 
diff --git a/tools/tracing/rtla/src/actions.h b/tools/tracing/rtla/src/actions.h
index a4f9b570775b5..439bcc58ac93a 100644
--- a/tools/tracing/rtla/src/actions.h
+++ b/tools/tracing/rtla/src/actions.h
@@ -42,7 +42,7 @@ struct actions {
 	struct tracefs_instance *trace_output_inst;
 };
 
-void actions_init(struct actions *self);
+int actions_init(struct actions *self);
 void actions_destroy(struct actions *self);
 int actions_add_trace_output(struct actions *self, const char *trace_output);
 int actions_add_signal(struct actions *self, int signal, int pid);
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 606c1688057b2..09a3da3f58630 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -798,8 +798,11 @@ static struct common_params
 	if (!params)
 		exit(1);
 
-	actions_init(&params->common.threshold_actions);
-	actions_init(&params->common.end_actions);
+	if (actions_init(&params->common.threshold_actions) ||
+	    actions_init(&params->common.end_actions)) {
+		err_msg("Error initializing actions");
+		exit(EXIT_FAILURE);
+	}
 
 	/* disabled by default */
 	params->dma_latency = -1;
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index fc479a0dcb597..7679820e72db5 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -556,8 +556,11 @@ static struct common_params
 	if (!params)
 		exit(1);
 
-	actions_init(&params->common.threshold_actions);
-	actions_init(&params->common.end_actions);
+	if (actions_init(&params->common.threshold_actions) ||
+	    actions_init(&params->common.end_actions)) {
+		err_msg("Error initializing actions");
+		exit(EXIT_FAILURE);
+	}
 
 	/* disabled by default */
 	params->dma_latency = -1;
-- 
2.51.1