diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 83a6f497c4e0..cb3860817fed 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -209,6 +209,9 @@ static int ext4_init_block_bitmap(struct super_block *sb,
 	memset(bh->b_data, 0, sb->s_blocksize);
 
 	bit_max = ext4_num_base_meta_clusters(sb, block_group);
+	if ((bit_max >> 3) >= bh->b_size)
+		return -EIO;
+
 	for (bit = 0; bit < bit_max; bit++)
 		ext4_set_bit(bit, bh->b_data);
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a5d94f263870..854801795882 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3668,6 +3668,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 	}
 
+	if (le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) > (blocksize / 4)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Number of reserved GDT blocks insanely large: %d",
+			 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks));
+		goto failed_mount;
+	}
+
 	if (sb->s_blocksize != blocksize) {
 		/* Validate the filesystem blocksize */
 		if (!sb_set_blocksize(sb, blocksize)) {