1 files changed, 28 insertions, 29 deletions

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 75bf1bcb4a8a..b3b5586f104d 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -9,7 +9,7 @@
  *
  */
 
-
+#include <linux/security.h>
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/rbtree.h>
@@ -72,9 +72,7 @@ static void destroy_session(struct stat_session *session)
 	kfree(session);
 }
 
-typedef int (*cmp_stat_t)(void *, void *);
-
-static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)
+static int insert_stat(struct rb_root *root, void *stat, cmp_func_t cmp)
 {
 	struct rb_node **new = &(root->rb_node), *parent = NULL;
 	struct stat_node *data;
@@ -112,7 +110,7 @@ static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)
  * This one will force an insertion as right-most node
  * in the rbtree.
  */
-static int dummy_cmp(void *p1, void *p2)
+static int dummy_cmp(const void *p1, const void *p2)
 {
 	return -1;
 }
@@ -130,7 +128,7 @@ static int stat_seq_init(struct stat_session *session)
 	int ret = 0;
 	int i;
 
-	mutex_lock(&session->stat_mutex);
+	guard(mutex)(&session->stat_mutex);
 	__reset_stat_session(session);
 
 	if (!ts->stat_cmp)
@@ -138,11 +136,11 @@ static int stat_seq_init(struct stat_session *session)
 
 	stat = ts->stat_start(ts);
 	if (!stat)
-		goto exit;
+		return 0;
 
 	ret = insert_stat(root, stat, ts->stat_cmp);
 	if (ret)
-		goto exit;
+		return ret;
 
 	/*
 	 * Iterate over the tracer stat entries and store them in an rbtree.
@@ -159,13 +157,10 @@ static int stat_seq_init(struct stat_session *session)
 			goto exit_free_rbtree;
 	}
 
-exit:
-	mutex_unlock(&session->stat_mutex);
 	return ret;
 
 exit_free_rbtree:
 	__reset_stat_session(session);
-	mutex_unlock(&session->stat_mutex);
 	return ret;
 }
 
@@ -238,6 +233,10 @@ static int tracing_stat_open(struct inode *inode, struct file *file)
 	struct seq_file *m;
 	struct stat_session *session = inode->i_private;
 
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
 	ret = stat_seq_init(session);
 	if (ret)
 		return ret;
@@ -274,26 +273,30 @@ static const struct file_operations tracing_stat_fops = {
 
 static int tracing_stat_init(void)
 {
-	struct dentry *d_tracing;
+	int ret;
 
-	d_tracing = tracing_init_dentry();
-	if (IS_ERR(d_tracing))
-		return 0;
+	ret = tracing_init_dentry();
+	if (ret)
+		return -ENODEV;
 
-	stat_dir = tracefs_create_dir("trace_stat", d_tracing);
-	if (!stat_dir)
+	stat_dir = tracefs_create_dir("trace_stat", NULL);
+	if (!stat_dir) {
 		pr_warn("Could not create tracefs 'trace_stat' entry\n");
+		return -ENOMEM;
+	}
 	return 0;
 }
 
 static int init_stat_file(struct stat_session *session)
 {
-	if (!stat_dir && tracing_stat_init())
-		return -ENODEV;
+	int ret;
 
-	session->file = tracefs_create_file(session->ts->name, 0644,
-					    stat_dir,
-					    session, &tracing_stat_fops);
+	if (!stat_dir && (ret = tracing_stat_init()))
+		return ret;
+
+	session->file = tracefs_create_file(session->ts->name, TRACE_MODE_WRITE,
+					    stat_dir, session,
+					    &tracing_stat_fops);
 	if (!session->file)
 		return -ENOMEM;
 	return 0;
@@ -310,15 +313,13 @@ int register_stat_tracer(struct tracer_stat *trace)
 	if (!trace->stat_start || !trace->stat_next || !trace->stat_show)
 		return -EINVAL;
 
+	guard(mutex)(&all_stat_sessions_mutex);
+
 	/* Already registered? */
-	mutex_lock(&all_stat_sessions_mutex);
 	list_for_each_entry(node, &all_stat_sessions, session_list) {
-		if (node->ts == trace) {
-			mutex_unlock(&all_stat_sessions_mutex);
+		if (node->ts == trace)
 			return -EINVAL;
-		}
 	}
-	mutex_unlock(&all_stat_sessions_mutex);
 
 	/* Init the session */
 	session = kzalloc(sizeof(*session), GFP_KERNEL);
@@ -336,9 +337,7 @@ int register_stat_tracer(struct tracer_stat *trace)
 	}
 
 	/* Register */
-	mutex_lock(&all_stat_sessions_mutex);
 	list_add_tail(&session->session_list, &all_stat_sessions);
-	mutex_unlock(&all_stat_sessions_mutex);
 
 	return 0;
 }