kernel-packages team mailing list archive

[Stefan Bader <stefan.bader@xxxxxxxxxxxxx>]

Hi Salvatore, so that old crash really looks quite similar. One
interesting difference is that this process did simply exit and was not
killed. Which sounds, like you did suspect as well, that this is not a
regression in a recent kernel but something in the way things are
executed changed and makes it just happen more often now.

I hear from James Page that right now some changes in OpenStack will
cause more things happen in parallel. That maybe causes some races to
get triggered which haven't been observed (that often) before.

To get a better understanding what the exact state of things is when
this happens, would it be possible to enable crashdump on one of the
development machines experiencing the issue and set it to panic on the
oops? A description how to set up crashdump you would find at
https://wiki.ubuntu.com/Kernel/CrashdumpRecipe. To cause the oops to
become a panic you would have to echo 1 into
/proc/sys/kernel/panic_on_oops after boot.

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You received this bug notification because you are a member of Kernel
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https://bugs.launchpad.net/bugs/1273386

Title:
  Neutron namespace metadata proxy triggers kernel crash on Ubuntu
  12.04/3.2 kernel

Status in OpenStack Neutron (virtual network service):
  New
Status in OpenStack Compute (Nova):
  New
Status in “linux” package in Ubuntu:
  Incomplete

Bug description:
  In the past 9 days we have been seeing very frequent occurences of
  this kernel crash: http://paste.openstack.org/show/61869/

  Even if the particular crash pasted here is triggered by dnsmasq, in
  almost all cases the crash is actually triggered by the neutron metada
  proxy.

  This also affects nova badly since this issue, which appears namespace
  related, results in a hang while mounting the ndb device for key
  injection.

  logstash query:
  http://logstash.openstack.org/#eyJzZWFyY2giOiJcImtlcm5lbCBCVUcgYXQgL2J1aWxkL2J1aWxkZC9saW51eC0zLjIuMC9mcy9idWZmZXIuYzoyOTE3XCIgYW5kIGZpbGVuYW1lOnN5c2xvZy50eHQiLCJmaWVsZHMiOltdLCJvZmZzZXQiOjAsInRpbWVmcmFtZSI6ImN1c3RvbSIsImdyYXBobW9kZSI6ImNvdW50IiwidGltZSI6eyJmcm9tIjoiMjAxNC0wMS0xNlQxODo1MDo0OCswMDowMCIsInRvIjoiMjAxNC0wMS0yN1QxOToxNjoxMSswMDowMCIsInVzZXJfaW50ZXJ2YWwiOiIwIn0sInN0YW1wIjoxMzkwODUwMzI2ODY0fQ==

  We have seen about 398 hits since the bug started to manifest.
  Decreased hit rate in the past few days is due to less neutron patches being pushed.

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