mtd: rawnand: Fix a memory leak bug

In nand_scan_bbt(), a temporary buffer 'buf' is allocated through
vmalloc(). However, if check_create() fails, 'buf' is not deallocated,
leading to a memory leak bug. To fix this issue, free 'buf' before
returning the error.
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/nand_bbt.c

@@ -1232,7 +1232,7 @@ static int nand_scan_bbt(struct nand_chip *this, struct nand_bbt_descr *bd)
 	if (!td) {
 		if ((res = nand_memory_bbt(this, bd))) {
 			pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
-			goto err;
+			goto err_free_bbt;
 		}
 		return 0;
 	}
@@ -1245,7 +1245,7 @@ static int nand_scan_bbt(struct nand_chip *this, struct nand_bbt_descr *bd)
 	buf = vmalloc(len);
 	if (!buf) {
 		res = -ENOMEM;
-		goto err;
+		goto err_free_bbt;
 	}
 
 	/* Is the bbt at a given page? */
@@ -1258,7 +1258,7 @@ static int nand_scan_bbt(struct nand_chip *this, struct nand_bbt_descr *bd)
 
 	res = check_create(this, buf, bd);
 	if (res)
-		goto err;
+		goto err_free_buf;
 
 	/* Prevent the bbt regions from erasing / writing */
 	mark_bbt_region(this, td);
@@ -1268,7 +1268,9 @@ static int nand_scan_bbt(struct nand_chip *this, struct nand_bbt_descr *bd)
 	vfree(buf);
 	return 0;
 
-err:
+err_free_buf:
+	vfree(buf);
+err_free_bbt:
 	kfree(this->bbt);
 	this->bbt = NULL;
 	return res;