[Xenial kernel] Only one cpu is successfully detected.
w90p710 at gmail.com
Wed Dec 7 09:55:45 UTC 2016
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
he used 4.4 kernel. I tried to bisect Xenial kernel tree, and found that
this bug was introduced by the following commit.
Author: Thomas Gleixner <tglx at linutronix.de>
Date: Mon Feb 22 22:19:15 2016 +0000
x86/topology: Create logical package id
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
the apic id is outside we map it to a logical package id if there
Provide interfaces for drivers to query the mapping and do
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 <jolsa at redhat.com>
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:
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