mtd: nand: fix pointer NULL pointer dereferencing

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=7912a5e7f37512d8d105785046137435b70347ce
Commit:     7912a5e7f37512d8d105785046137435b70347ce
Parent:     7b7e905ec2ec511e06279181ca95a892db21e292
Author:     Stanislav Fomichev <kernel at fomichev.me>
AuthorDate: Mon Feb 7 23:48:25 2011 +0300
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Fri Mar 11 14:22:44 2011 +0000

    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 at fomichev.me>
    Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/nand/nand_bbt.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 6ebd869..a1e8b30 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);