Messages in this thread | | | Subject | Re: [v4.6-rc1 Regression] x86/topology: Create logical package id | From | Joseph Salisbury <> | Date | Fri, 6 May 2016 16:50:13 -0400 |
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On 05/06/2016 03:38 PM, Joseph Salisbury wrote: > On 05/06/2016 02:48 PM, Thomas Gleixner wrote: >> 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); >> >> /* > I'll have this patch tested and report back. > > Thanks, > > Joe Yes, your patch does in fact fix the bug. Would you like any additional information regarding the bug?
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