System entirely freezes--keyboard, mouse no use

[Peter Brandon]

I recently upgraded to the xenial LTS hardware enablement stack for 14.04. Wily was working like a charm. Now, periodically my system freezes. My mouse stops working (doesn't even get power), keyboard is unresponsive (though it is getting power, as indicated when I switch my mouse to the keyboard usb slot, still mouse doesn't work). Ctrl-alt-F4 etc. do not switch me to an alternate terminal. I have to do a hard shut down. Everything works fine after reboot, till the next system freeze. I wonder if doing an upgrade to 16.04 will solve this issue or make matters worse.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-4.4.0-34-generic 4.4.0-34.53~14.04.1
ProcVersionSignature: Ubuntu 4.4.0-34.53~14.04.1-generic 4.4.15
Uname: Linux 4.4.0-34-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.21
Architecture: amd64
CurrentDesktop: KDE
Date: Sat Aug 27 17:45:25 2016
InstallationDate: Installed on 2014-04-20 (860 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
SourcePackage: linux-lts-xenial
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Ante Kirt (ddrraaqqll)]

This same thing happens to me after upgrading to kernel 4.8. Switching back to 4.4 is a temporary solution though not ideal.

[Ante Kirt (ddrraaqqll)]

What other environment data shall i post here?

[Ante Kirt (ddrraaqqll)]

Even further tested and it is between kernels 4.4 and 4.8. Definitely.

[Eric Desrochers (slashd)]

Hi Ante/Peter,

Based on your previous comment, it seems like Ubuntu kernel v4.4 doesn't exhibit the hang but ubuntu kernel v4.8 does ?

If it's the case, then can you reproduce the problematic with the same mainline kernel versions[1] ?

If yes, then I recommend you to shorten to amount of commits by testing the mainline kernels between the two until you have shorten enough to start a kernel bisection[2]

Assuming the hang doesn't collect any informations in /var/log/ nor provide a stacktrace when it hangs.

You can also enable the crashdump mechanism[3] + enabling enabling via sysctl various types of panic conditions[4] for the kernel to panic immediately under these conditions.

Example :

kernel.hardlockup_panic = 1
kernel.hung_task_panic = 1
kernel.panic_on_io_nmi = 1
kernel.panic_on_oops = 1
kernel.panic_on_unrecovered_nmi = 1
kernel.panic_on_warn = 1
kernel.softlockup_panic = 1
kernel.unknown_nmi_panic = 1
vm.panic_on_oom = 1

[1] - http://kernel.ubuntu.com/~kernel-ppa/mainline/
[2] - https://wiki.ubuntu.com/Kernel/KernelBisection
[3] - https://wiki.ubuntu.com/Kernel/CrashdumpRecipe
[4] - https://www.kernel.org/doc/Documentation/sysctl/kernel.txt

Hope it helps !

[Eric Desrochers (slashd)]

With crashdump enabled, hopefully you could then get a vmcore under /var/crash that will provide more informations as of why the system hangs.

[Ante Kirt (ddrraaqqll)]

Hi Eric,

|As it happens, I just re-started testing new kernels yesterday and so far 4.8.0.32 seems to work, no hangs yet. (Reminder: this used to happen mostly before login but also sometimes after hours of working). I will keep on testing and you guys updated.

[Launchpad Janitor (janitor)]

[Expired for linux-lts-xenial (Ubuntu) because there has been no activity for 60 days.]