diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 4045a9b..6944aac 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -1611,13 +1611,14 @@ struct pblk_line *pblk_line_replace_data(struct pblk *pblk)
 	struct pblk_line *cur, *new = NULL;
 	unsigned int left_seblks;
 
-	cur = l_mg->data_line;
 	new = l_mg->data_next;
 	if (!new)
 		goto out;
-	l_mg->data_line = new;
 
 	spin_lock(&l_mg->free_lock);
+	cur = l_mg->data_line;
+	l_mg->data_line = new;
+
 	pblk_line_setup_metadata(new, l_mg, &pblk->lm);
 	spin_unlock(&l_mg->free_lock);
 
diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c
index cba83ac..2d28181 100644
--- a/drivers/lightnvm/pblk-sysfs.c
+++ b/drivers/lightnvm/pblk-sysfs.c
@@ -263,8 +263,14 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
 		sec_in_line = l_mg->data_line->sec_in_line;
 		meta_weight = bitmap_weight(&l_mg->meta_bitmap,
 							PBLK_DATA_LINES);
-		map_weight = bitmap_weight(l_mg->data_line->map_bitmap,
+
+		spin_lock(&l_mg->data_line->lock);
+		if (l_mg->data_line->map_bitmap)
+			map_weight = bitmap_weight(l_mg->data_line->map_bitmap,
 							lm->sec_per_line);
+		else
+			map_weight = 0;
+		spin_unlock(&l_mg->data_line->lock);
 	}
 	spin_unlock(&l_mg->free_lock);