On the contrary I would say we can be quite sure this is *not* a re-introduction of the TSC problem. As I wrote in the other bug report, this time we do not have unusual high process times. In other words the time stays increments normally after boot. It is just this one jump at boot. And the jump is caused by the guest using the hosts uptime in the kernel. Visible effect is just the dmesg times being in the far(er) future. And the jump happens exactly at that time when the guest starts to use a time structure provided by the host. Normally that contains the hosts uptime but also a correcting offset which is supposed to adjust the time value to a zero value at the guests boot. Since I cannot reproduce this with my Xen guests (Xen 4.1 or later) this does indicate to me that maybe EC2 hosts toolstack have a bug there. I think I only saw the jump with EC2 Xen 3.x but since I don't know how to enforce landing on a certain Xen version in EC2 it would be really tedious for me to compare.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1349883 Title: dmesg time wildly incorrect on paravirtual EC2 instances. Status in “linux” package in Ubuntu: Confirmed Bug description: On Ubuntu 14.04 EC2 instances, during startup the dmesg time goes from 0 seconds to thousands of seconds. This causes kernel logs to be recorded for months in the future. This appears to be related to the kernel trusting the TSC clock on Xen servers, as described here: https://forums.aws.amazon.com/thread.jspa?threadID=59753 But I am not sure that is the cause. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.13.0-32-generic 3.13.0-32.57 ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4 Uname: Linux 3.13.0-32-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Jul 29 14:41 seq crw-rw---- 1 root audio 116, 33 Jul 29 14:41 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.14.1-0ubuntu3.2 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CRDA: Error: [Errno 2] No such file or directory: 'iw' CurrentDmesg: [7562292.301737] init: plymouth-upstart-bridge main process ended, respawning Date: Tue Jul 29 14:47:54 2014 Ec2AMI: ami-00dc1368 Ec2AMIManifest: (unknown) Ec2AvailabilityZone: us-east-1c Ec2InstanceType: m1.small Ec2Kernel: aki-919dcaf8 Ec2Ramdisk: unavailable IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lspci: Lsusb: Error: [Errno 2] No such file or directory: 'lsusb' PciMultimedia: ProcEnviron: TERM=xterm PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: ProcKernelCmdLine: root=LABEL=cloudimg-rootfs ro console=hvc0 RelatedPackageVersions: linux-restricted-modules-3.13.0-32-generic N/A linux-backports-modules-3.13.0-32-generic N/A linux-firmware N/A RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) WifiSyslog: --- AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Jul 29 14:41 seq crw-rw---- 1 root audio 116, 33 Jul 29 14:41 timer AplayDevices: Error: [Errno 2] No such file or directory ApportVersion: 2.14.1-0ubuntu3.2 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CRDA: Error: [Errno 2] No such file or directory CurrentDmesg: [7562292.301737] init: plymouth-upstart-bridge main process ended, respawning DistroRelease: Ubuntu 14.04 Ec2AMI: ami-00dc1368 Ec2AMIManifest: (unknown) Ec2AvailabilityZone: us-east-1c Ec2InstanceType: m1.small Ec2Kernel: aki-919dcaf8 Ec2Ramdisk: unavailable IwConfig: Error: [Errno 2] No such file or directory Lspci: Lsusb: Error: [Errno 2] No such file or directory Package: linux (not installed) PciMultimedia: ProcEnviron: TERM=xterm PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: ProcKernelCmdLine: root=LABEL=cloudimg-rootfs ro console=hvc0 ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4 RelatedPackageVersions: linux-restricted-modules-3.13.0-32-generic N/A linux-backports-modules-3.13.0-32-generic N/A linux-firmware N/A RfKill: Error: [Errno 2] No such file or directory Tags: trusty ec2-images Uname: Linux 3.13.0-32-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm admin ssh sudo WifiSyslog: _MarkForUpload: True To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1349883/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
