[kwlug-disc] Meltown fix for Linux kernel

[Khalid Baheyeldin]

I looked at the pages documenting 'pinning' of .deb packages, and it seems
to be an overly complex task.

Any ideas on how to bypass kernel upgrades while applying updates for other
packages to go through?

On Wed, Jan 10, 2018 at 9:24 AM, Khalid Baheyeldin <kb at 2bits.com> wrote:

> Wow, the differences are significant ...
>
> For a dedicated server, the fix for Meltdown is not really needed, since
> no one else is accessing RAM by exploiting the speculative execution.
>
> So I am thinking of pinning the kernel to what it is on those machines.
>
> But there are also headers, generic, ...etc.
>
> Anyone tried that?
>
>
>
> On Wed, Jan 10, 2018 at 8:31 AM, L.D. Paniak <ldpaniak at fourpisolutions.com
> > wrote:
>
>> Looks like you will see substantial performance impact for I/O-heavy
>> workloads (especially synthetic ones):
>>
>> https://www.phoronix.com/scan.php?page=news_item&px=KPTI-Ret
>> poline-Combined-Ubuntu
>>
>> The Apache server numbers are especially notable.
>>
>>
>>
>> On 01/09/2018 07:18 PM, doug moen wrote:
>>
>> According to what I read, the performance impact occurs if you are
>> hammering the kernel with a lot of system calls. Eg, a server that is
>> performing a lot of I/o.
>>
>> On Tuesday, 9 January 2018, Khalid Baheyeldin <kb at 2bits.com> wrote:
>>
>>> I just received the email for the meltdown patch for Ubuntu Linux.
>>>
>>> CVE-2017-5754
>>>
>>> There are two concerns:
>>>
>>> 1. Performance impact.
>>>
>>> 2. This comment in the email:
>>>
>>> "ATTENTION: Due to an unavoidable ABI change the kernel updates have
>>> been given a new version number, which requires you to recompile and
>>> reinstall all third party kernel modules you might have installed.
>>> Unless you manually uninstalled the standard kernel metapackages
>>> (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
>>> linux-powerpc), a standard system upgrade will automatically perform
>>> this as well."
>>>
>>> Anyone updated to this fix yet?
>>> Any noticeable negative impact on performance?
>>>
>>> --
>>> Khalid M. Baheyeldin
>>> 2bits.com, Inc.
>>> Fast Reliable Drupal
>>> Drupal optimization, development, customization and consulting.
>>> Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
>>> Simplicity is the ultimate sophistication. --   Leonardo da Vinci
>>> For every complex problem, there is an answer that is clear, simple, and
>>> wrong." -- H.L. Mencken
>>>
>>
>>
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>>
>>
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>
>
> --
> Khalid M. Baheyeldin
> 2bits.com, Inc.
> Fast Reliable Drupal
> Drupal optimization, development, customization and consulting.
> Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
> Simplicity is the ultimate sophistication. --   Leonardo da Vinci
> For every complex problem, there is an answer that is clear, simple, and
> wrong." -- H.L. Mencken
>



-- 
Khalid M. Baheyeldin
2bits.com, Inc.
Fast Reliable Drupal
Drupal optimization, development, customization and consulting.
Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
Simplicity is the ultimate sophistication. --   Leonardo da Vinci
For every complex problem, there is an answer that is clear, simple, and
wrong." -- H.L. Mencken
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