[Qemu-devel] [Bug 1359394] [NEW] virtio block device hangs after "virtio_blk virtio3: requests:id 0 is not a head!"

[Qemu-devel] [Bug 1359394] [NEW] virtio block device hangs after "virtio_blk virtio3: requests:id 0 is not a head!"

[Slava Pestov]

Public bug reported:

The virtual machine is running block layer workloads, interrupted by
unclean reboots (echo b > /proc/sysrq-trigger). Kernel version is 3.14.

Sometimes, I get this message on boot:

"virtio_blk virtio3: requests:id 0 is not a head!"

Then, I/O to the virtio block devices just hangs.

Unfortunately I don't have a test case and this is kind of hard to
reproduce, but it seems related to having I/O in flight when the kernel
is forced to reboot.

** Affects: qemu
     Importance: Undecided
         Status: New

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Title:
  virtio block device hangs after "virtio_blk virtio3: requests:id 0 is
  not a head!"

Status in QEMU:
  New

Bug description:
  The virtual machine is running block layer workloads, interrupted by
  unclean reboots (echo b > /proc/sysrq-trigger). Kernel version is
  3.14.

  Sometimes, I get this message on boot:

  "virtio_blk virtio3: requests:id 0 is not a head!"

  Then, I/O to the virtio block devices just hangs.

  Unfortunately I don't have a test case and this is kind of hard to
  reproduce, but it seems related to having I/O in flight when the
  kernel is forced to reboot.

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Re: [Qemu-devel] [Bug 1359394] [NEW] virtio block device hangs after "virtio_blk virtio3: requests:id 0 is not a head!"

[Stefan Hajnoczi]

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On Wed, Aug 20, 2014 at 08:37:46PM -0000, Slava Pestov wrote:
> The virtual machine is running block layer workloads, interrupted by
> unclean reboots (echo b > /proc/sysrq-trigger). Kernel version is 3.14.
> 
> Sometimes, I get this message on boot:
> 
> "virtio_blk virtio3: requests:id 0 is not a head!"
> 
> Then, I/O to the virtio block devices just hangs.
> 
> Unfortunately I don't have a test case and this is kind of hard to
> reproduce, but it seems related to having I/O in flight when the kernel
> is forced to reboot.

Hi Slava,
Sounds like the virtio device was not reset properly.

The guest kernel is looking for completed responses from the host.  The
host has indicated that descriptor 0 is the next completed response but
the guest does not remember having submitted it.

Do you have a kernel stack trace when this was encountered?

Stefan

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[Qemu-devel] [Bug 1359394] Re: virtio block device hangs after "virtio_blk virtio3: requests:id 0 is not a head!"

[Slava Pestov]

You mean a kernel stack trace when the message was printed? I don't have
that but I guess I could add a dump_stack() call in there.

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https://bugs.launchpad.net/bugs/1359394

Title:
  virtio block device hangs after "virtio_blk virtio3: requests:id 0 is
  not a head!"

Status in QEMU:
  New

Bug description:
  The virtual machine is running block layer workloads, interrupted by
  unclean reboots (echo b > /proc/sysrq-trigger). Kernel version is
  3.14.

  Sometimes, I get this message on boot:

  "virtio_blk virtio3: requests:id 0 is not a head!"

  Then, I/O to the virtio block devices just hangs.

  Unfortunately I don't have a test case and this is kind of hard to
  reproduce, but it seems related to having I/O in flight when the
  kernel is forced to reboot.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1359394/+subscriptions

[Qemu-devel] [Bug 1359394] Re: virtio block device hangs after "virtio_blk virtio3: requests:id 0 is not a head!"

[Thomas Huth]

Triaging old bug tickets ... can you still reproduce this issue with the
latest version of QEMU and the kernel?

** Changed in: qemu
       Status: New => Incomplete

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You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1359394

Title:
  virtio block device hangs after "virtio_blk virtio3: requests:id 0 is
  not a head!"

Status in QEMU:
  Incomplete

Bug description:
  The virtual machine is running block layer workloads, interrupted by
  unclean reboots (echo b > /proc/sysrq-trigger). Kernel version is
  3.14.

  Sometimes, I get this message on boot:

  "virtio_blk virtio3: requests:id 0 is not a head!"

  Then, I/O to the virtio block devices just hangs.

  Unfortunately I don't have a test case and this is kind of hard to
  reproduce, but it seems related to having I/O in flight when the
  kernel is forced to reboot.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1359394/+subscriptions

[Qemu-devel] [Bug 1359394] Re: virtio block device hangs after "virtio_blk virtio3: requests:id 0 is not a head!"

[Launchpad Bug Tracker]

[Expired for QEMU because there has been no activity for 60 days.]

** Changed in: qemu
       Status: Incomplete => Expired

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Title:
  virtio block device hangs after "virtio_blk virtio3: requests:id 0 is
  not a head!"

Status in QEMU:
  Expired

Bug description:
  The virtual machine is running block layer workloads, interrupted by
  unclean reboots (echo b > /proc/sysrq-trigger). Kernel version is
  3.14.

  Sometimes, I get this message on boot:

  "virtio_blk virtio3: requests:id 0 is not a head!"

  Then, I/O to the virtio block devices just hangs.

  Unfortunately I don't have a test case and this is kind of hard to
  reproduce, but it seems related to having I/O in flight when the
  kernel is forced to reboot.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1359394/+subscriptions