"value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix double-free of blocks due to wrong extents moved_len\n\nIn ext4_move_extents(), moved_len is only updated when all moves are\nsuccessfully executed, and only discards orig_inode and donor_inode\npreallocations when moved_len is not zero. When the loop fails to exit\nafter successfully moving some extents, moved_len is not updated and\nremains at 0, so it does not discard the preallocations.\n\nIf the moved extents overlap with the preallocated extents, the\noverlapped extents are freed twice in ext4_mb_release_inode_pa() and\next4_process_freed_data() (as described in commit 94d7c16cbbbd (\"ext4:\nFix double-free of blocks with EXT4_IOC_MOVE_EXT\")), and bb_free is\nincremented twice. Hence when trim is executed, a zero-division bug is\ntriggered in mb_update_avg_fragment_size() because bb_free is not zero\nand bb_fragments is zero.\n\nTherefore, update move_len after each extent move to avoid the issue."
