Comment 2 for bug 718717

Feb 14 11:53:46 ubuntu kernel: [ 5577.334589] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
Feb 14 11:53:46 ubuntu kernel: [ 5577.334594] ata1.00: BMDMA stat 0x24
Feb 14 11:53:46 ubuntu kernel: [ 5577.334597] ata1.00: failed command: READ DMA
Feb 14 11:53:46 ubuntu kernel: [ 5577.334603] ata1.00: cmd c8/00:b0:58:2a:00/00:00:00:00:00/e0 tag 0 dma 90112 in
Feb 14 11:53:46 ubuntu kernel: [ 5577.334604] res 51/40:00:79:2a:00/00:00:00:00:00/e0 Emask 0x9 (media error)
Feb 14 11:53:46 ubuntu kernel: [ 5577.334607] ata1.00: status: { DRDY ERR }
Feb 14 11:53:46 ubuntu kernel: [ 5577.334610] ata1.00: error: { UNC }
Feb 14 11:53:46 ubuntu kernel: [ 5577.340501] ata1: nv_mode_filter: 0x3f39f&0x3f39f->0x3f39f, BIOS=0x3f000 (0xc6000000) ACPI=0x3f01f (20:900:0x11)
Feb 14 11:53:46 ubuntu kernel: [ 5577.356964] ata1.00: configured for UDMA/100
Feb 14 11:53:46 ubuntu kernel: [ 5577.356981] sd 0:0:0:0: [sda] Unhandled sense code
Feb 14 11:53:46 ubuntu kernel: [ 5577.356984] sd 0:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
Feb 14 11:53:46 ubuntu kernel: [ 5577.356988] sd 0:0:0:0: [sda] Sense Key : Medium Error [current] [descriptor]
Feb 14 11:53:46 ubuntu kernel: [ 5577.356993] Descriptor sense data with sense descriptors (in hex):
Feb 14 11:53:46 ubuntu kernel: [ 5577.356995] 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
Feb 14 11:53:46 ubuntu kernel: [ 5577.357006] 00 00 2a 79
Feb 14 11:53:46 ubuntu kernel: [ 5577.357010] sd 0:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed
Feb 14 11:53:46 ubuntu kernel: [ 5577.357016] sd 0:0:0:0: [sda] CDB: Read(10): 28 00 00 00 2a 58 00 00 b0 00
Feb 14 11:53:46 ubuntu kernel: [ 5577.357026] end_request: I/O error, dev sda, sector 10873
Feb 14 11:53:46 ubuntu kernel: [ 5577.357040] EXT4-fs error (device sda1): __ext4_get_inode_loc: unable to read inode block - inode=3386, block=1119
Feb 14 11:53:46 ubuntu kernel: [ 5577.357046] ata1: EH complete
Feb 14 11:53:46 ubuntu kernel: [ 5577.357048] Aborting journal on device sda1-8.
Feb 14 11:53:46 ubuntu kernel: [ 5577.359246] EXT4-fs (sda1): Remounting filesystem read-only

In other words, the target hard disk suddenly got very unhappy about the time we were trying to install the boot loader, and it all went wrong from there. If it was a USB stick, perhaps you jolted it or something?

At any rate, this error was much lower-level than the installer code, and not something the installer can do anything much about. It might be worth repeating the installation and seeing if it happens again ...