Windows

Earlier I wrote about Hyper-V crashing with BSOD. The entire project was doomed from the beginning. After I managed get the Windows not to crash, all I managed to do is get the Linux installer to hang whenever it attempted to anything major on the hard drive. I configured Hyper-V to provide the hard drive from a .vhdx-file, so I initially suspected that old .vhd-file might help, but no, nothing helped. Any minor operations succeeded, but any sort of normal usage made the Linux to hang.

Symptoms include:

• Console message: "INFO: task jbd2/sda blocked for more than 120 seconds" and instruction to deactivate the warning with:
  echo 0 > /proc/sys/kernel/hung_task_timeout_secs
  Example:
  • http://helpinlinux.com/tag/echo-0-proc-sys-kernel-hung_task_timeout_secs/
• Repeated "Sense Key" -messages in dmesg, example:
  • http://forums.gentoo.org/viewtopic-t-734696-view-next.html?sid=64f39476a9b96703e2a2c998023729b9
• No change in /sys/block/sda/stat:
  • Kernel documentation about block-device stat says that columns 3 and 6 contain the number of sectors read and written.
  • In my hung box, the values don't increase.

I was puzzled about this for a very long time. It took me several hours to bump into Linux-SCSI mailing list's discussion about the issue. There Mr. Olaf Hering describes an issue "storvsc loops with No Sense messages".

Luckily Mr. Hering realized what's going on and made a patch to fix the problem. Unfortunately the fix is not yet pushed into mainstream Linux kernel.

Since I was about to install ArchLinux, I took the trouble of compiling the necessary kernel module of hv_storvsc.ko into following kernel versions:

• 3.8.4, used in installation ISO-image:
  • SHA-1 sum: 74d2a5de73a4c7d963b649eb34b171eba86a268c
• 3.8.6, the version that got installed when I got my install done:
  • SHA-1 sum: 57a4216fc6749085820703d47cd87dcce47b1739
• 3.8.7, the version that it upgraded into when I did a system update:
  • SHA-1 sum: 3f8757ab69c97a6389c7c83a8ef57f16e9caa85d

All of the packages are available for you to download at http://opensource.hqcodeshop.com/ArchLinux/2013.04.01/. Your only trick is to get them replaced into initial RAM-disk -image. I just replaced the original file at /usr/lib/modules and re-ran the mkinitrd-command.

Since most modern Intel CPUs have VT-x in them and Windows 8 Pro has Hyper-V in it, I had to make use of the combo on my old laptop. It has a i5 mobile CPU which makes it on the less powerful end of CPUs. But the simple existence of a possibility of running a Linux on top of a Windows laptop makes me want to try it.

I added the Hyper-V feature into my Windows. I started the Hyper-V Management Console, added a virtual network switch and created a new virtual machine. It booted into Linux installer and the entire Windows crashed with a blue-screen-of-death. WTF?!

After a number of attempts with tweaking the Hyper-V settings, no avail. Every attempt to actually do anything reasonable in the guest system yielded a BSOD. Couple more futile attempts on command-line indicated that it had to have something to do with networking.

Next day I managed to Google into one discussion thread on Microsoft's social forums. There another unfortunate user is experiencing the same symptoms than me. Unlike his Windows 7, on my Windows 8 BSOD there isn't much of a stack trace or any usable information. But I had to try something, so I took an Ethernet-cable and plugged it into my laptop and reconfigured the Hyper-V virtual switch not to use the Intel Centrino 6200 WLAN, but a 1 Gbit/s Realtek port. That did the trick! Apparently some network drivers are not Hyper-V compatible. I don't know how to tell the difference between functioning or not functioning driver, but it is there.

There seems to be some sort of issue with hard drive, but that's an another story ...