udev event for md setup sent too early

[Ian Jackson]

Binary package hint: linux-source-2.6.20

During the feisty rc testing, fabbione had a test system with the following symptoms: The underlying md* device(s) would start properly, but the lvm made out of those would not.

The symptoms were not reproduceable with udevd --verbose so we have no corresponding udev log, so we investigated by instrumenting the udev rules.

We discovered that the vgscan,vgchange udev rule was not being executed for the md device; investigating further showed that the vol_id rule in 65-persistent-storage was being run twice but each time vol_id reported "unknown volume type".

We concluded that the kernel has sent the change udev event for the md activation too early - at a point where the device is not yet properly readable. This causes vol_id to fail to identify the raid as an lvm pv, and vgscan,vgchange is not run.

We were able to "fix" the problem on the troubled system by inserting, just before the call to vol_id in 65-persistent-storage.rules, a call to a script which polls once a second for up to 5 seconds waiting for vol_id $tempnode to exit nonzero.

[Ian Jackson (ijackson)]

I have added a Malone task for mdadm so that the bug contacts for mdadm will get mails about this bug, even though we think there is not a bug in mdadm here.

[Launchpad Janitor (janitor)]

Beginning with the Hardy Heron 8.04 development cycle, all open Ubuntu kernel bugs need to be reported against the "linux" kernel package. We are automatically migrating this bug to the new "linux" package. However, development has already began for the upcoming Intrepid Ibex 8.10 release. It would be helpful if you could test the upcoming release and verify if this is still an issue - http://www.ubuntu.com/testing . If the issue still exists, please update this report by changing the Status of the "linux" task from "Incomplete" to "New". We appreciate your patience and understanding as we make this transition. Thanks!

[Leann Ogasawara (leannogasawara)]

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

[xteejx (xteejx-deactivatedaccount)]

We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New". Thanks again!