diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 2fbdff6..87cceed 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -280,6 +280,11 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
 	 * sd->s_parent won't change beneath us.
 	 */
 	parent_sd = sd->s_parent;
+	if(!(sd->s_flags & SYSFS_FLAG_REMOVED)) {
+		printk("%s-%d sysfs_dirent use after free: %s-%s\n",
+			__func__, __LINE__, parent_sd->s_name, sd->s_name);
+		dump_stack();
+	}
 
 	if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
 		sysfs_put(sd->s_symlink.target_sd);
@@ -962,6 +967,12 @@ static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
 		int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
 			pos->s_parent == parent_sd &&
 			hash == pos->s_hash;
+
+		if ((atomic_read(&pos->s_count) == 1)) {
+			printk("%s-%d sysfs_dirent use after free: %s(%s)-%s, %lld-%u\n",
+				__func__, __LINE__, parent_sd->s_name, pos->s_parent->s_name,
+				pos->s_name, hash, pos->s_hash);
+		}
 		sysfs_put(pos);
 		if (!valid)
 			pos = NULL;
@@ -1008,7 +1019,7 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
 	struct dentry *dentry = filp->f_path.dentry;
 	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
-	struct sysfs_dirent *pos = filp->private_data;
+	struct sysfs_dirent *pos;
 	enum kobj_ns_type type;
 	const void *ns;
 	ino_t ino;
@@ -1016,6 +1027,7 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 	type = sysfs_ns_type(parent_sd);
 	ns = sysfs_info(dentry->d_sb)->ns[type];
 
+	mutex_lock(&sysfs_mutex);
 	if (filp->f_pos == 0) {
 		ino = parent_sd->s_ino;
 		if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
@@ -1029,7 +1041,7 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 		if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
 			filp->f_pos++;
 	}
-	mutex_lock(&sysfs_mutex);
+	pos = filp->private_data;
 	for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
 	     pos;
 	     pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
@@ -1044,17 +1056,15 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 		filp->f_pos = pos->s_hash;
 		filp->private_data = sysfs_get(pos);
 
-		mutex_unlock(&sysfs_mutex);
 		ret = filldir(dirent, name, len, filp->f_pos, ino, type);
-		mutex_lock(&sysfs_mutex);
 		if (ret < 0)
 			break;
 	}
-	mutex_unlock(&sysfs_mutex);
 	if ((filp->f_pos > 1) && !pos) { /* EOF */
 		filp->f_pos = INT_MAX;
 		filp->private_data = NULL;
 	}
+	mutex_unlock(&sysfs_mutex);
 	return 0;
 }