<div dir="ltr"><div>The origin of the story is from here<br><br><a href="http://pythonsweetness.tumblr.com/post/169166980422/the-mysterious-case-of-the-linux-page-table">http://pythonsweetness.tumblr.com/post/169166980422/the-mysterious-case-of-the-linux-page-table</a><br><br></div>L.<br></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>------<br>"The antidote to apocalypticism is
<strong>apocalyptic civics</strong>. Apocalyptic civics is the
insistence that we cannot ignore the truth, nor should we panic about
it. It is a shared consciousness that our institutions have failed and
our ecosystem is collapsing, yet we are still here — and we are creative
agents who can shape our destinies. Apocalyptic civics is the
conviction that the only way out is through, and the only way through is
together. "<br><br><i>Greg Bloom</i> @greggish <a href="https://twitter.com/greggish/status/873177525903609857" target="_blank">https://twitter.com/greggish/status/873177525903609857</a><br></div></div></div></div></div></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On 3 January 2018 at 19:46, John Hearns via Beowulf <span dir="ltr"><<a href="mailto:beowulf@beowulf.org" target="_blank">beowulf@beowulf.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Thanks Chris. In the past there have been Intel CPU 'bugs' trumpeted, but generally these are fixed with a microcode update. </div><div>This looks different, as it is a fundamental part of the chips architecture.</div><div>However the Register article says: "<span style="text-align:left;color:rgb(0,0,0);text-transform:none;text-indent:0px;letter-spacing:normal;font-family:"Arimo","Arial","FreeSans","Helvetica","sans-serif";font-size:15.93px;font-style:normal;font-variant:normal;font-weight:400;text-decoration:none;word-spacing:0px;display:inline;white-space:normal;float:none;background-color:transparent">It allows normal user programs – to discern to some extent the layout or contents of protected kernel memory areas"</span></div><div><br></div><div>I guess the phrase "to some extent" is the vital one here. Are there any security exploits which use this information? I guess it is inevitable that one will be engineered now that this is known about. The question I am really asking is should we worry about this for real world systems. And I guess tha answer is that if the kernel developers are worried enough then yes we should be too. Comments please.</div><div><br></div><div><br></div><div><br></div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On 3 January 2018 at 06:56, Greg Lindahl <span dir="ltr"><<a href="mailto:lindahl@pbm.com" target="_blank">lindahl@pbm.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>On Wed, Jan 03, 2018 at 02:46:07PM +1100, Christopher Samuel wrote:<br>
<br>
> There appears to be no microcode fix possible and the kernel fix will<br>
> incur a significant performance penalty, people are talking about in the<br>
> range of 5%-30% depending on the generation of the CPU. :-(<br>
<br>
</span>The performance hit (at least for the current patches) is related to<br>
system calls, which HPC programs using networking gear like OmniPath<br>
or Infiniband don't do much of.<br>
<span class="m_-135617569790858489HOEnZb"><font color="#888888"><br>
-- greg<br>
</font></span><div class="m_-135617569790858489HOEnZb"><div class="m_-135617569790858489h5"><br>
<br>
______________________________<wbr>_________________<br>
Beowulf mailing list, <a href="mailto:Beowulf@beowulf.org" target="_blank">Beowulf@beowulf.org</a> sponsored by Penguin Computing<br>
To change your subscription (digest mode or unsubscribe) visit <a href="http://www.beowulf.org/mailman/listinfo/beowulf" rel="noreferrer" target="_blank">http://www.beowulf.org/mailman<wbr>/listinfo/beowulf</a><br>
</div></div></blockquote></div><br></div>
</div></div><br>______________________________<wbr>_________________<br>
Beowulf mailing list, <a href="mailto:Beowulf@beowulf.org">Beowulf@beowulf.org</a> sponsored by Penguin Computing<br>
To change your subscription (digest mode or unsubscribe) visit <a href="http://www.beowulf.org/mailman/listinfo/beowulf" rel="noreferrer" target="_blank">http://www.beowulf.org/<wbr>mailman/listinfo/beowulf</a><br>
<br></blockquote></div><br></div>