Hard lockup but certain UI elements keeps changing

[Shuhao]

I recently upgraded to Wily and I discovered that my system hard freezes about 2-3 times a day. This is the usual: unresponsive keyboard (including magic sysrq), unresponsive USB, no response to pings over the network, music/audio loops, as well as no evidence of errors in syslog, kern.log, Xorg.log.

However, there's one very unusual aspect of this lockup: I have an on screen clock to the second and when the lockup occurs, the clock keeps ticking by the second! This means that code must be executing somewhere... This happened all but one occurance of hard freeze, where the clock also froze. In fact, I was on Facebook at one point and saw that I was disconnected. The facebook UI then followed up with the animation of "Reconnecting... 10... 9... 8...".

I feel like posting here is a very long shot, but maybe someone else has something similar.

Next time this happens I'll try to hook this machine to ethernet to see if there's any response and try to ssh into it. I could also write a program that writes to syslog every 5 seconds and see if those get written when the machine is "locked up". Not sure what else I can do at this point. I can also memtest or play kernel roulette with mainline, but the machine was previously stable on utopic (with BIOS instead of UEFI boot, tho).

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: linux-image-4.2.0-16-generic 4.2.0-16.19 [modified: boot/vmlinuz-4.2.0-16-generic]
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
ApportVersion: 2.19.1-0ubuntu3
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: shuhao 1884 F.... pulseaudio
CurrentDesktop: XFCE
Date: Thu Oct 22 17:49:21 2015
HibernationDevice: RESUME=UUID=0b162d26-cb30-4f74-b80c-6cd03fd55a69
InstallationDate: Installed on 2015-10-14 (8 days ago)
InstallationMedia: Xubuntu 15.10 "Wily Werewolf" - Alpha amd64 (20151013)
MachineType: LENOVO 4180J4C
ProcEnviron:
 LANGUAGE=en_CA:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_CA.UTF-8
 SHELL=/bin/zsh
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.2.0-16-generic.efi.signed root=/dev/mapper/xubuntu--vg-root ro noprompt quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.2.0-16-generic N/A
 linux-backports-modules-4.2.0-16-generic N/A
 linux-firmware 1.149
SourcePackage: linux
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/05/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 83ET76WW (1.46 )
dmi.board.asset.tag: Not Available
dmi.board.name: 4180J4C
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr83ET76WW(1.46):bd07/05/2013:svnLENOVO:pn4180J4C:pvrThinkPadT420:rvnLENOVO:rn4180J4C:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 4180J4C
dmi.product.version: ThinkPad T420
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[Shuhao (shuhao)]

Why was this made confirmed? Does it happen on someone elses' as well? In the same manner?

[penalvch (penalvch)]

Shuhao, thank you for reporting this and helping make Ubuntu better.

To advised, it notes in comment #2 that it's a bot.

Despite this, could you please test the latest upstream kernel available from the very top line at the top of the page from http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D (the release names are irrelevant for testing, and please do not test the daily folder)? Install instructions are available at https://wiki.ubuntu.com/Kernel/MainlineBuilds . This will allow additional upstream developers to examine the issue.

If the latest kernel did not allow you to test to the issue (ex. you couldn't boot into the OS) please make a comment in your report about this, and continue to test the next most recent kernel version until you can test to the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this issue is fixed in the mainline kernel, please add the following tags by clicking on the yellow circle with a black pencil icon, next to the word Tags, located at the bottom of the report description:
kernel-fixed-upstream
kernel-fixed-upstream-X.Y-rcZ

Where X, Y, and Z are numbers corresponding to the kernel version.

If the mainline kernel does not fix the issue, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-X.Y-rcZ

Please note, an error to install the kernel does not fit the criteria of kernel-bug-exists-upstream.

Once testing of the latest upstream kernel is complete, please mark this report's Status as Confirmed. Please let us know your results.

Thank you for your understanding.

[Shuhao (shuhao)]

I've been running 4.3.0-rc6 for a week or so without any lockups so I'm inclined to think this is a kernel issue (interaction?).

Since 4.3 just was released, I can take a look and see if that works as well.

[Shuhao (shuhao)]

Marking this as invalid for now. I've observed one additional event on 4.3 and now I'm back on 4.2-18 and haven't noticed this for a couple of days.

Makes me wonder if this might be solar activity.

[Shuhao (shuhao)]

Back on 4.2.0-18-generic. Experience this once per day. Screen keeps changing but no more response to any input. May just be hardware giving out.

[Launchpad Janitor (janitor)]

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

[penalvch (penalvch)]

Shuhao, regarding hardware giving out, one could test the laptop for this via:
http://support.lenovo.com/us/en/products/Laptops-and-netbooks/ThinkPad-T-Series-laptops/ThinkPad-T420?linkTrack=Homepage:Body_Search%20Products

and:
https://help.ubuntu.com/community/Checkbox

Could you please advise to the results?

[Launchpad Janitor (janitor)]

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