[precise, trusty] udev does not automatically load modules with kernel >= 3.11

[Pali]

Udev version in Ubuntu 12.04 LTS Precise does not load all modules automatically. This is know bug in udev which was fixed more than one year ago in upstream project.

Specially this bug cause that no module with cpu modalias is loaded for kernels >= 3.11.

More info is on ML:
http://lists.freedesktop.org/archives/systemd-devel/2013-July/012165.html

Upstream patch which fixing this bug is simple and one-line:
http://cgit.freedesktop.org/systemd/systemd/commit/?id=bf7f800f2b3e93ccd1229d4717166f3a4d3af72f

Please backport this patch to Ubuntu 12.04 LTS. It should be simple as it is one-line patch and should not have any regressions. It is also in upstream udev project.

[Martin Pitt (pitti)]

Note that this is not unambiguously regression free -- in precise we did not yet have kmod, and udev still calls the modprobe binary instead of using libkmod. So as Kay already pointed out, we'd call modprobe a lot more with this, even on the default precise kerneL (3.2).

[Martin Pitt (pitti)]

Do you have a concrete use case here for testing the fix on precise?

[Pali (pali)]

Yes I have: coretemp.ko module which show temperature of intel core processors. Or other intel modules like x86_pkg_temp_thermal, intel_powerclamp, intel_rapl. Or intel module aesni-intel.ko which use intel AES-NI instructions for optimizes AES support in kernel (e.g. for luks/dm-crypt).

All these modules have cpu alias in module binary so without that patch they are not automatically loaded.

Test case is easy: just start precise on those intel core processors and check if above modules were automatically loaded.

[Martin Pitt (pitti)]

This also affects 14.04 LTS, although to a slightly lesser degree. In 14.04 we have a patch which does the modprobing for the "cpu" subsystem; but reportedly this also affects drivers of other platforms, so let's just backport that more generic upstream fix to cover all cases.

This can potentially cause a lot more attempts to load nonexisting modules, and thus affect boot speed a bit. For 14.04 we have a builtin kmod which is really fast to fail, so the impact should be negligible. It might be measurable on 12.04 on some systems, but then again as we do ship backported kernels on 12.04 and officially support them we don't have much choice here.

[Martin Pitt (pitti)]

Trusty SRU uploaded to SRU review queue.

[Martin Pitt (pitti)]

Precise SRU uploaded to SRU review queue.

[Pali (pali)]

@Martin Pitt (pitti): Another regression for precise kernel is with VFAT filesystem and fsck, please look at bug #1322976.

[Chris J Arges (arges)]

Hello Pali, or anyone else affected,

Accepted systemd into trusty-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/systemd/204-5ubuntu20.10 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Chris J Arges (arges)]

Hello Pali, or anyone else affected,

Accepted udev into precise-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/udev/175-0ubuntu9.9 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Pali (pali)]

Tested on Ubuntu 12.04 machine and intel coretemp, rapl and other modules were automatically loaded after installing new udev version.

[Chris J Arges (arges)]

The verification of the Stable Release Update for udev has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package udev - 175-0ubuntu9.9

---------------
udev (175-0ubuntu9.9) precise; urgency=medium

  * Add load-modules-for-bound-devices.patch: Always probe modules, even when
    a driver is already bound to a device. Fixes some modules not loading
    automatically when using kernel backports > 3.11. Patch backported from
    upstream commit and adjusted to use modprobe. (LP: #1404509)
 -- Martin Pitt <email address hidden> Fri, 23 Jan 2015 08:22:52 +0100

[Mark W Wenning (mwenning)]

Tested and verified on PowerEdge R620 with trusty-proposed.
After updating and dist-upgrade, /dev/ipmi0 shows up as a device.

[Pali (pali)]

Martin Pitt (pitti): Can you look also at bug #1322976 which is there because of new kernel versions in precise?

[Launchpad Janitor (janitor)]

This bug was fixed in the package systemd - 204-5ubuntu20.10

---------------
systemd (204-5ubuntu20.10) trusty; urgency=medium

  * Replace our always-probe-cpu-support-drivers.patch (which is specific to
    the "cpu" subsystem) with the more generic upstream fix which also applies
    to other subsystems. Fixes some modules not loading automatically when
    using kernel backports > 3.11. (LP: #1404509)
 -- Martin Pitt <email address hidden> Fri, 23 Jan 2015 08:18:59 +0100