Xen Kernel cannot boot due to ATA erros/timeouts

[Anes Lihovac]

In week 6 or 7 after an system update , my Xen host stopped booting.
When booting up the Xen Kernel, it will timeout and drop to initramfs shell. DMESG will show ATA errors/timeouts not finding my harddisk(s). The same system with the same Kernel but xen-less, boots and works without problems.

I tried several things :
1. adding all the modules which my xen-less system would have loaded to the initramfs -> no change
2. switching from ahci to ide mode in bios -> no success
3. changing uuid for root with its real block ids (like sda3, etc) in grub -> no change in boot behaviour
4. blkid in initramfs shell shows nothing !
5. boot Xen with an older installed Kernel Version (3.2.0-23-generic ) -> same problem
6. cat /proc/partitions shows nothing besides my cdrom(sr0)
7. recreate initrds
8. reinstall whole 12.04

I was able to save the DMESG output from the initramfs shell. The system would recognize a plugged in USB thumb drive, which I just needed to mount manually.

Due to the fact that it worked before updates fromn week 6 or 7 (soory I am not sure) but doesn't work when choosing an older kernel, it looks like it is not up to the Kernel, but something else, which I am affraid I cannot find.

[Anes Lihovac (anes-lihovac-gmail)]

I just compiled vanilla xen-4.2.1. This hypervisor version will boot as normal as it had it before week 6 or 7. I guess some update broke something in the Ubuntu hypervisor package.

[Anes Lihovac (anes-lihovac-gmail)]

After checking again 4.2.1, I am prett sure this is due to changes in 4.1.x xen-hypervisor in Ubuntu repos.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Simon Déziel (sdeziel)]

My Saucy dom0 is also affected by this. I wasn't able to get the dmesg in text but I attached a picture of it.

The problem seems to be this:

 ata1.00: qc timeout (cmd 0xec)
 ata1.00: failed to IDENTIFY (I/O error, err_mask=0x4)

Then the SATA link back down a on speed (6 -> 3 Gbps) and the same occurs over and over.

The same kernel boots just fine when outside of Xen.

System info:

$ lsb_release -rd
Description: Ubuntu 13.10
Release: 13.10

$ apt-cache policy linux-image-`uname -r` xen-hypervisor-4.3-amd64
linux-image-3.11.0-13-generic:
  Installed: 3.11.0-13.20
  Candidate: 3.11.0-13.20
  Version table:
 *** 3.11.0-13.20 0
        500 http://archive.ubuntu.com/ubuntu/ saucy-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ saucy-security/main amd64 Packages
        100 /var/lib/dpkg/status
xen-hypervisor-4.3-amd64:
  Installed: 4.3.0-1ubuntu1
  Candidate: 4.3.0-1ubuntu1
  Version table:
 *** 4.3.0-1ubuntu1 0
        500 http://archive.ubuntu.com/ubuntu/ saucy/universe amd64 Packages
        100 /var/lib/dpkg/status

[Simon Déziel (sdeziel)]

Here is the dmesg of the *non dom0* kernel that boots properly.