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Commit fdff73f0 authored by Theodore Ts'o's avatar Theodore Ts'o
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ext4: Initialize the new group descriptor when resizing the filesystem 

Make sure all of the fields of the group descriptor are properly
initialized.  Previously, we allowed bg_flags field to be contain
random garbage, which could trigger non-deterministic behavior,
including a kernel OOPS.

http://bugzilla.kernel.org/show_bug.cgi?id=12433



Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
parent e7f07968

fs/ext4/resize.c

+2 −1
Original line number Diff line number Diff line
@@ -861,12 +861,13 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input) 
	gdp = (struct ext4_group_desc *)((char *)primary->b_data +

					 gdb_off * EXT4_DESC_SIZE(sb));



	memset(gdp, 0, EXT4_DESC_SIZE(sb));

	ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */

	ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */

	ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */

	ext4_free_blks_set(sb, gdp, input->free_blocks_count);

	ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));

	gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);

	gdp->bg_flags = cpu_to_le16(EXT4_BG_INODE_ZEROED);

	gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);



	/*