Comment by fotcorn

9 years ago

The latest intel-microcode package from Ubuntu 16.04 does not fix the problem. I installed the same package from Ubuntu 17.10 [0] which fixes the problem. You can check your system with the script linked in the mailing list thread [1].

[0] https://packages.ubuntu.com/en/artful/amd64/intel-microcode/...

[1] https://lists.debian.org/debian-devel/2017/06/msg00309.html

13 comments

fotcorn

Reply
arde  9 years ago

Indeed, the latest Intel microcode published for Ubuntu 16.04 is the ancient 20151106 [1]. Later Ubuntu releases do have more recent microcode packages [2]. I cannot understand why they left out 16.04 there. So much for LTS, it seems.

This recently came to my attention while debugging some increasingly frequent lockups, which took me a solid week of eliminating all seemingly more likely causes (VirtualBox, nVidia driver, faulty RAM, etc). In the end I found the culprit while digging into the Intel Specification updates: my Core i7-5820K (and most other Haswell-E and Broadwell processors) has a bug when leaving package C-states, and the only workaround is to disable C-states above level 1. Timely updated microcode, which applies this workaround, would have saved me my week.

[1] https://launchpad.net/ubuntu/xenial/+source/intel-microcode [2] https://launchpad.net/ubuntu/+source/intel-microcode/+change...

  • rlpb  9 years ago

    > Indeed, the latest Intel microcode published for Ubuntu 16.04 is the ancient 20151106.

    By ancient, perhaps you mean the version that was current at the time 16.04 shipped?

    > I cannot understand why they left out 16.04 there. So much for LTS, it seems.

    See https://wiki.ubuntu.com/StableReleaseUpdates. The point of an LTS (or any stable release, for that matter) is that it doesn't change by default. For those who want to keep everything up-to-date, Ubuntu ships a new release on a six month cadence. If you choose not to use that, then you shouldn't be surprised when things aren't updated, since that's exactly what you opted in to.

    The microcode package may warrant an exception, however, and we have a bug to track that. It's tricky because without the source we cannot pick apart what changed, or determine whether any changes meet our update policy. We have to be careful. Sooner or later some user will inevitably come along to tell us that a microcode update broke things, and ask why we didn't fulfill our LTS promise by not changing it.

    • arde  9 years ago

      By ancient I mean that it is 1.7 years old and by now Intel has published 4 later releases (20160607, 20160714, 20161104 and 20170511). I think it's a fair and tame adjective considering this is processor microcode we're talking about and that it made me spend a week of my own time hunting it.

      You say Ubuntu has a bug to track the microcode package as an exception, but that doesn't seem to be having a positive effect, does it? Precisely because Ubuntu cannot pick it apart, what is it that they're trying to decide in the bug? Why is Ubuntu second guessing Intel in deciding which microcode update to apply and which to skip? How would Ubuntu know that better than the manufacturer? The Intel specification updates list tons of processor bugs including some very critical ones, so we know the microcode updates do help with some of those. When was the last time that an Intel microcode update brought a new bug or made something worse? I'm not aware of any such instance, and although that may indeed happen sometime it doesn't seem as likely as facing existing known bugs, right?

      I think it could be argued that it is up to the user to decide (say, a warning during installation), or that Ubuntu could choose to apply all microcode updates by default and let the user opt out. Ubuntu might impose a certain delay, say a month or two at most, in order to see if a microcode update gets withdrawn or ends up too buggy. But I don't think Ubuntu could reasonably choose to skip all microcode updates for 1.7 years like it did in my case, or to choose which ones to apply and which ones to skip, like it seems to be trying to. Microcode should be treated like other propietary software, but with special dilligence due to its criticality. If nVidia says a particular driver release is very buggy and should be updated, Ubuntu promptly updates it. Why would Ubuntu sit on known critical microcode updates then? If, and it's really a big if, eventually some microcode update brings a new bug and Ubuntu deployed it, it would be Intel's fault and not Ubuntu's.

      7 replies →

gt565k  9 years ago

How do you check if the issue is actually fixed after installing the microcode fix?