Ubuntu kernels above version 2.6.35-25 fail to load > 50% of the time

[Andrew Somerville]

Hopefully the apport contains enough specific information about my system. Ever since Ubuntu 10.10 moved on from release 25 of the 2.6.35 kernel, it's taken several hard resets to get my system to complete an initialisation of the kernel and continue to boot. When I was still running 10.10, I continued to select release 25 of the 2.6.35 kernel as it was the only one that reliably booted for me. All newer versions failed to complete the kernel initialisation, even in debug mode.

Following the debug output was not particularly revealing. On several occasions I took note of the last message printed by the kernel after a failure to boot. The freezes occurred during CPU initialisation, during USB initialisation, during SATA initialisation, etc... In other words, never the same twice, pointing possibly to a race condition or another timing problem.

Once the system boots it's perfectly stable with all hardware working properly. But by my count it will only complete the kernel initialisation less than 1/6 of the time. As someone who's done a little bit of system programming on multicore systems, this looks very much to me like a race condition, where a lock isn't being set where/when it should be. Since I'm booting from an SSD, something might be getting loaded sooner than it normally would be. At the moment I'm running 11.04 2.6.38-8-generic and can reproduce this bug easily, if anyone has any ideas how I might go about providing the information necessary to debug it and find the cause.

As I don't reboot often and prefer to use standby, I'm able to continue using ubuntu despite how difficult it is to achieve a successful boot-up. Since upgrading to 11.04 I no longer have access to 2.6.35-25, so if someone could give me a hint as to how to revert to that kernel version, I'd very much appreciate it as well.

In case it matters, the release after 2.5.35-25 was also the release where bug #642421 went away.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: linux-image (not installed)
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: andrew 2620 F.... pulseaudio
 /dev/snd/controlC1: andrew 2620 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'SB'/'HDA ATI SB at 0xfe024000 irq 16'
   Mixer name : 'Realtek ALC889A'
   Components : 'HDA:10ec0885,1458a102,00100101'
   Controls : 41
   Simple ctrls : 23
Card1.Amixer.info:
 Card hw:1 'REC'/'Roland UA-30 (44100Hz, Analog REC) at usb-0000:00:12.2-5.4, full speed'
   Mixer name : 'USB Mixer'
   Components : 'USB0582:0006'
   Controls : 5
   Simple ctrls : 4
Card2.Amixer.info:
 Card hw:2 'NVidia'/'HDA NVidia at 0xfcffc000 irq 19'
   Mixer name : 'Nvidia GPU 14 HDMI/DP'
   Components : 'HDA:10de0014,10de0101,00100100'
   Controls : 16
   Simple ctrls : 4
Date: Tue Apr 26 13:26:29 2011
HibernationDevice: RESUME=UUID=971a8c8f-9be9-42b3-ba91-caeedce785f0
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100427.1)
IwConfig:
 lo no wireless extensions.

 eth0 no wireless extensions.
MachineType: Gigabyte Technology Co., Ltd. GA-MA785GM-US2H
ProcEnviron:
 LANGUAGE=en_CA:en
 PATH=(custom, no user)
 LANG=en_CA.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=112f2a44-ad93-4e66-8243-225f59538ddd ro single
RelatedPackageVersions:
 linux-restricted-modules-2.6.38-8-generic N/A
 linux-backports-modules-2.6.38-8-generic N/A
 linux-firmware 1.52
RfKill:

SourcePackage: linux
UpgradeStatus: Upgraded to natty on 2011-04-16 (10 days ago)
dmi.bios.date: 06/22/2009
dmi.bios.vendor: Award Software International, Inc.
dmi.bios.version: F2
dmi.board.name: GA-MA785GM-US2H
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.type: 3
dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF2:bd06/22/2009:svnGigabyteTechnologyCo.,Ltd.:pnGA-MA785GM-US2H:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnGA-MA785GM-US2H:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
dmi.product.name: GA-MA785GM-US2H
dmi.sys.vendor: Gigabyte Technology Co., Ltd.

[Andrew Somerville (andy16666)]

It seems that this issue went away after I disconnected a particular USB hub. It seems a strange thing to cause an issue like this, but that appears to have been the cause.