linux-kernel - [PATCH ftrace/core 3/3] trace: Fix memory leak when new instance creation failed

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Date:	Fri, 06 Jun 2014 07:35:22 +0900
From:	Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
To:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>
Cc:	Hidehiro Kawai <hidehiro.kawai.ez@...achi.com>,
	Ingo Molnar <mingo@...hat.com>, yrl.pp-manager.tt@...achi.com
Subject: [PATCH ftrace/core 3/3] trace: Fix memory leak when new instance
 creation failed

Current new_instance_create() implements just two fail paths for four
allocation operations. So, it can induce memory leak if new instance
creation failed. This patch fixes it by defining all fail paths and
freeing allocated memories appropriately.

Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: linux-kernel@...r.kernel.org
---
 kernel/trace/trace.c |   23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 473eb68..bbd86d2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6277,7 +6277,7 @@ static int new_instance_create(const char *name)
 		goto out_free_tr;
 
 	if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
-		goto out_free_tr;
+		goto out_free_tr_name;
 
 	cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
 
@@ -6291,16 +6291,16 @@ static int new_instance_create(const char *name)
 	INIT_LIST_HEAD(&tr->events);
 
 	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
-		goto out_free_tr;
+		goto out_free_cpumask_var;
 
 	tr->dir = debugfs_create_dir(name, trace_instance_dir);
 	if (!tr->dir)
-		goto out_free_tr;
+		goto out_free_trace_buffers;
 
 	ret = event_trace_add_tracer(tr->dir, tr);
 	if (ret) {
 		debugfs_remove_recursive(tr->dir);
-		goto out_free_tr;
+		goto out_free_trace_buffers;
 	}
 
 	init_tracer_debugfs(tr, tr->dir);
@@ -6311,18 +6311,23 @@ static int new_instance_create(const char *name)
 
 	return 0;
 
- out_free_tr:
-	if (tr->trace_buffer.buffer)
-		ring_buffer_free(tr->trace_buffer.buffer);
+ out_free_trace_buffers:
+	ring_buffer_free(tr->trace_buffer.buffer);
+	free_percpu(tr->trace_buffer.data);
+#ifdef CONFIG_TRACER_MAX_TRACE
+	ring_buffer_free(tr->max_buffer.buffer);
+	free_percpu(tr->max_buffer.data);
+#endif
+ out_free_cpumask_var:
 	free_cpumask_var(tr->tracing_cpumask);
+ out_free_tr_name:
 	kfree(tr->name);
+ out_free_tr:
 	kfree(tr);
-
  out_unlock:
 	mutex_unlock(&trace_types_lock);
 
 	return ret;
-
 }
 
 static int instance_delete(const char *name)

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