mtd: mtdpart: prevent a read from regions[-1]

If the erase region was found in the first iteration we read from
regions[-1]

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 349fcbe5cc0f..a83cfa1ad122 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -453,7 +453,8 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
                 for (i = 0; i < max && regions[i].offset <= slave->offset; i++)
                         ;
                 /* The loop searched for the region _behind_ the first one */
-                i--;
+                if (i > 0)
+                        i--;
 
                 /* Pick biggest erasesize */
                 for (; i < max && regions[i].offset < end; i++) {