Boot hangs on 3.19.0-30

[brb]

I recently upgraded to 3.19.0-30-generic and booting my laptop has started freezing at the encryption prompt. I found https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1502598 which seems to describe the same problem. I followed the instructions in #4 and was able to successfully boot with the 4.3.0-040300rc4-generic kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.3-rc4-unstable/.

Note that the logs in this report are from 3.19.0-15-generic which I had to boot into to run `ubuntu-bug`.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-3.19.0-15-generic 3.19.0-15.15 [modified: boot/vmlinuz-3.19.0-15-generic]
ProcVersionSignature: Ubuntu 3.19.0-15.15-generic 3.19.3
Uname: Linux 3.19.0-15-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: brb 1458 F.... pulseaudio
 /dev/snd/controlC0: brb 1458 F.... pulseaudio
CurrentDesktop: Unity
Date: Sun Oct 4 21:52:43 2015
HibernationDevice: RESUME=UUID=cc858711-9333-4c0c-818c-f33eb1bf03b3
InstallationDate: Installed on 2015-10-05 (0 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MachineType: LENOVO 20CMCTO1WW
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.19.0-15-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro quiet splash
RelatedPackageVersions:
 linux-restricted-modules-3.19.0-15-generic N/A
 linux-backports-modules-3.19.0-15-generic N/A
 linux-firmware 1.143.3
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: 08/20/2015
dmi.bios.vendor: LENOVO
dmi.bios.version: N10ET38W (1.17 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20CMCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0K11826 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN10ET38W(1.17):bd08/20/2015:svnLENOVO:pn20CMCTO1WW:pvrThinkPadX250:rvnLENOVO:rn20CMCTO1WW:rvrSDK0K11826WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.name: 20CMCTO1WW
dmi.product.version: ThinkPad X250
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[penalvch (penalvch)]

brb, thank you for reporting this and helping make Ubuntu better. The next step is to fully reverse commit bisect from kernel 3.19 to 4.3-rc4 in order to identify the last bad commit, followed immediately by the first good one. Once this commit has been identified, then it may be reviewed as a candidate for backporting into your release. Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection#How_do_I_reverse_bisect_the_upstream_kernel.3F ?

Please note, finding adjacent kernel versions is not fully commit bisecting.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Launchpad Janitor (janitor)]

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