From: Stanislav Fomichev <kernel@fomichev.me>
Date: Mon, 7 Feb 2011 20:48:25 +0000 (+0300)
Subject: mtd: nand: fix pointer NULL pointer dereferencing
X-Git-Tag: firefly_0821_release~7613^2~1768^2~34
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7912a5e7f37512d8d105785046137435b70347ce;p=firefly-linux-kernel-4.4.55.git

mtd: nand: fix pointer NULL pointer dereferencing

In 'verify_bbt_descr()', first check the "bd" pointer, then
dereference it.

Comments amended by Artem.

Signed-off-by: Stanislav Fomichev <kernel@fomichev.me>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---

diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 6ebd869993aa..a1e8b30078d9 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -1101,12 +1101,16 @@ static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
 static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 {
 	struct nand_chip *this = mtd->priv;
-	u32 pattern_len = bd->len;
-	u32 bits = bd->options & NAND_BBT_NRBITS_MSK;
+	u32 pattern_len;
+	u32 bits;
 	u32 table_size;
 
 	if (!bd)
 		return;
+
+	pattern_len = bd->len;
+	bits = bd->options & NAND_BBT_NRBITS_MSK;
+
 	BUG_ON((this->options & NAND_USE_FLASH_BBT_NO_OOB) &&
 			!(this->options & NAND_USE_FLASH_BBT));
 	BUG_ON(!bits);