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1f2acb6017
Add checks to ext4_free_branches() to make sure a block number found in an indirect block are valid before trying to free it. If a bad block number is found, stop freeing the indirect block immediately, since the file system is corrupt and we will need to run fsck anyway. This also avoids spamming the logs, and specifically avoids driver-level "attempt to access beyond end of device" errors obscure what is really going on. If you get *really*, *really*, *really* unlucky, without this patch, a supposed indirect block containing garbage might contain a reference to a primary block group descriptor, in which case ext4_free_branches() could end up zero'ing out a block group descriptor block, and if then one of the block bitmaps for a block group described by that bg descriptor block is not in memory, and is read in by ext4_read_block_bitmap(). This function calls ext4_valid_block_bitmap(), which assumes that bg_inode_table() was validated at mount time and hasn't been modified since. Since this assumption is no longer valid, it's possible for the value (ext4_inode_table(sb, desc) - group_first_block) to go negative, which will cause ext4_find_next_zero_bit() to trigger a kernel GPF. Addresses-Google-Bug: #2220436 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
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| .. | ||
| acl.c | ||
| acl.h | ||
| balloc.c | ||
| bitmap.c | ||
| block_validity.c | ||
| dir.c | ||
| ext4_extents.h | ||
| ext4_jbd2.c | ||
| ext4_jbd2.h | ||
| ext4.h | ||
| extents.c | ||
| file.c | ||
| fsync.c | ||
| hash.c | ||
| ialloc.c | ||
| inode.c | ||
| ioctl.c | ||
| Kconfig | ||
| Makefile | ||
| mballoc.c | ||
| mballoc.h | ||
| migrate.c | ||
| move_extent.c | ||
| namei.c | ||
| resize.c | ||
| super.c | ||
| symlink.c | ||
| xattr_security.c | ||
| xattr_trusted.c | ||
| xattr_user.c | ||
| xattr.c | ||
| xattr.h | ||