Init in VM segfault if NFS-client installed in guest KVM system

[RussianNeuroMancer]

Init in VM segfault on boot if NFS-client installed in guest KVM system and there is at least one NFS share in fstab. Please look at attached calltraces taken from Precise and Quantal VM's.
Host system is Quantal (3.5.0-17-generic) upgraded from Precise (upgraded without any errors). This regression appear only after upgrade so I guess this issue related to Linux 3.5.

Testing of upstream 3.6 kernel is impossible due to another regression.

What additional information I need to provide?

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1065831

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Joseph Salisbury (jsalisbury)]

Did this issue only start happening after you upgraded the *host* to Quantal ?

[RussianNeuroMancer (russianneuromancer)]

> Did this issue only start happening after you upgraded the *host* to Quantal ?
Yes.

[Joseph Salisbury (jsalisbury)]

Do you happen to know if there is a prior Quantal kernel version that did not have the bug?

[RussianNeuroMancer (russianneuromancer)]

Init segfault is reproducible even on kernels that works for me before on Precise. More specifically I have same init segfault with 3.2.0-31 on host and 3.2.0-31 in guest VM (backtrace attached).
If I mount NFS shares using mount CL utility or script that exacute on boot there is no init segfault - that results of at least one day testing of this issue in different VM's on different kernels (host & guest).

[RussianNeuroMancer (russianneuromancer)]

With Linux 3.8 behaviour is a little bit different, but system still doesn't boot - kernel panic.

[penalvch (penalvch)]

RussianNeuroMancer, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run from your host (not the guest) the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p linux <replace-with-bug-number>

If reproducible, could you also please test on your host the latest upstream kernel available (not the daily folder) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-v3.13-rc6

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]