diff --git a/[refs] b/[refs]
index 1b614af957a9..bdc91dbe9de0 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4c1e6b2ce13b154a4a69cee220c98976f4b784df
+refs/heads/master: ebf2e93036907fe2a7ddab942aa63d35f97f3b2b
diff --git a/trunk/drivers/mtd/mtdconcat.c b/trunk/drivers/mtd/mtdconcat.c
index 792b547786b8..db6de74082ad 100644
--- a/trunk/drivers/mtd/mtdconcat.c
+++ b/trunk/drivers/mtd/mtdconcat.c
@@ -427,7 +427,7 @@ static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 		 * to-be-erased area begins. Verify that the starting
 		 * offset is aligned to this region's erase size:
 		 */
-		if (instr->addr & (erase_regions[i].erasesize - 1))
+		if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 			return -EINVAL;
 
 		/*
@@ -440,8 +440,8 @@ static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 		/*
 		 * check if the ending offset is aligned to this region's erase size
 		 */
-		if ((instr->addr + instr->len) & (erase_regions[i].erasesize -
-						  1))
+		if (i < 0 || ((instr->addr + instr->len) &
+					(erase_regions[i].erasesize - 1)))
 			return -EINVAL;
 	}