[kwlug-disc] Meltown fix for Linux kernel

[doug moen]

The Ubuntu bug is here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1742323

The problem is that, after upgrading to kernel 4.4.0-108, some systems
won't boot.

Most people with this problem report that upgrading to 4.4.0-109 (which is
now in the Ubuntu repositories) fixes the problem.

However, bug 1742323 is still open and being worked on (marked critical).

On 10 January 2018 at 18:04, Khalid Baheyeldin <kb at 2bits.com> wrote:

> And Ubuntu 16.04 users can't reboot the new kernel after applying the
> fixes.
>
> Not a big deal if it is a desktop. If it is a dedicated server in a data
> center, then it is downtime + support headaches.
>
> https://news.slashdot.org/story/18/01/10/1634215/
> meltdown-and-spectre-patches-bricking-ubuntu-1604-computers
>
> 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
>
> _______________________________________________
> kwlug-disc mailing list
> kwlug-disc at kwlug.org
> http://kwlug.org/mailman/listinfo/kwlug-disc_kwlug.org
>
>
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