This is caused by this commit from mainline: linux-aws: 9f182bd x86/microcode/intel: Extend BDW late-loading further with LLC size check mainline: 7e702d1 x86/microcode/intel: Extend BDW late-loading further with LLC size check
which adds a check which involves this computation: + do_div(llc_size, c->x86_max_cores); But dmesg on a c3.large instance yields this interesting line: [ 0.156084] smpboot: x86_max_cores == zero !?!? ** Changed in: linux (Ubuntu) Assignee: (unassigned) => Kamal Mostafa (kamalmostafa) ** Changed in: linux (Ubuntu) Status: Triaged => In Progress -- 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/1758869 Title: Kernel panic with AWS 4.4.0-1053 / 4.4.0-1015 (Trusty) Status in linux package in Ubuntu: In Progress Bug description: This is a POTENTIAL REGRESSION. This issue only occurs on one of the AWS testing instance "c3.large" Reproduce rate: 100% (All jenkins deployment job failed with this instance) Steps: 1. Deploy this instance with AWS kernel (4.4.0-1052) 2. Enable -proposed, upgrade it and reboot. Result: * System can boot with 4.4.0-1052, but it won't be accessible after rebooting for 4.4.0-1053, from "aws ec2 get-console-output" command indicates it hang with kernel panic issue on boot. It looks like the intel-microcode is causing this issue. Output from the command: https://pastebin.ubuntu.com/p/3JvWNk5CTs/ (it's a bit difficult to get full output, the instance will keep rebooting itself) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1758869/+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