Messages in this thread Patch in this message | | | Date | Fri, 6 May 2016 20:48:16 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [v4.6-rc1 Regression] x86/topology: Create logical package id |
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On Fri, 6 May 2016, Joseph Salisbury wrote: > A kernel bug report was opened against Ubuntu [0]. After a kernel > bisect, it was found that reverting the following commit resolved this bug: > > commit 1f12e32f4cd5243ae46d8b933181be0d022c6793 > Author: Thomas Gleixner <tglx@linutronix.de> > Date: Mon Feb 22 22:19:15 2016 +0000 > > x86/topology: Create logical package id > > To build successfully with this commit reverted, I also had to revert > commits: e7ee3e8,2d4de83,87f01cc and 33c3cc7. > > The regression was introduced as of v4.6-rc1. > > I was hoping to get your feedback, since you are the patch author. Do > you think gathering any additional data will help diagnose this issue, > or would it be best to submit a revert request?
Yuck. That dies with a divide error. And that looks like XEN is supplying crap data in the CPUID.
Does the patch below cure the issue?
Thanks,
tglx
8<---------------
--- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -332,6 +332,11 @@ static void __init smp_init_package_map( * primary cores. */ ncpus = boot_cpu_data.x86_max_cores; + if (!ncpus) { + pr_warn("x86_max_cores == zero !?!?"); + ncpus = 1; + } + __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus); /*
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