The kernel bug manifests when mounting of nbd devices is combined with ip namespace operations. Using openstack it can be reproduced only with the following configuration: - compute service must run on the same node as the dhcp-agent and/or the l3-agent - file injection should be turned on: libvirt.inject_partition != -2 - key injection should be enabled: libvirt.inject_key = True - config drive should be disabled: force_config_drive = 'False' or empty string or None
If these conditions are met, nbd mount will be used to inject the key into the instance. This will trigger something in the kernel which subsequently will cause the crash in a process running in a network namespace. After this crash nbd mount won't work anymore. Using openstack the crash can be reproduced within a few minutes with the scripts available here: https://gist.github.com/salv-orlando/8715991 - keep_booting_stuff.sh creates and destroys vms continuously, ensuring a key is always injected - stress_me_to_death creates network namespaces, launches a process in them, kills the process and then the namespace The two scripts require openstack and should be executed concurrently. Crashdump data will posted as soon as possible. It should not be too hard to provide a script that reproduces the issue and is indepedent from openstack. ** Changed in: neutron Status: New => Triaged -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. 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): Triaged 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. To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1273386/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
