Public bug reported: Hi team,,
I have a customer, who tried to install Xenial or upgrade to 4.4 kernel with Trusty on our cloud platform(qemu 1.5.3), reports a defect. he complains that only one cpu is successfully detected, other cpus is disabled if he used 4.4 kernel. I tried to bisect Xenial kernel tree, and found that this bug was introduced by the following commit. commit 31c2013e4ea2e594522980acc3d20e88664b19f1 Author: Thomas Gleixner <[email protected]> Date: Mon Feb 22 22:19:15 2016 +0000 x86/topology: Create logical package id BugLink: http://bugs.launchpad.net/bugs/1397880 For per package oriented services we must be able to rely on the number of CPU packages to be within bounds. Create a tracking facility, which - calculates the number of possible packages depending on nr_cpu_ids after boot - makes sure that the package id is within the number of possible packages. If the apic id is outside we map it to a logical package id if there is enough space available. Provide interfaces for drivers to query the mapping and do translations from physcial to logical ids. and then I backported 7b0501b1e7cddd32b265178e32d332bdfbb532d4 from Linus tree to Xenial kernel, the issue goes away, so could we consider to backport it to xenial kernel tree to solve this issue in next release? >From 7b0501b1e7cddd32b265178e32d332bdfbb532d4 Mon Sep 17 00:00:00 2001 From: Jiri Olsa <[email protected]> Date: Mon, 15 Aug 2016 12:17:00 +0200 Subject: [PATCH] x86/smp: Fix __max_logical_packages value setup Frank reported kernel panic when he disabled several cores in BIOS via following option: Thanks Wei ** Affects: linux (Ubuntu) Importance: Undecided Status: Fix Released ** Affects: linux (Ubuntu Xenial) Importance: Undecided Assignee: Tim Gardner (timg-tpi) Status: In Progress ** Also affects: linux (Ubuntu Xenial) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1648088 Title: linux - Memory Bandwidth Monitoring regression To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1648088/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
