Multiple off-by-one errors in the ext4 subsystem in the Linux kernel before 3.0-rc5 allow local users to cause a denial of service (BUG_ON and system crash) by accessing a sparse file in extent format with a write operation involving a block number corresponding to the largest possible 32-bit unsigned integer.
https://bugzilla.redhat.com/show_bug.cgi?id=722557
http://www.openwall.com/lists/oss-security/2011/07/15/8
http://www.openwall.com/lists/oss-security/2011/07/15/7