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I'll apply the patch and see if <b><i>(i) </i></b>liblitmus
compiles without warnings/errors, and <i><b>(ii) </b></i>tasks can
be successfully assigned into cores when number of cores is greater
than 48.<br>
<br>
Thanks<br>
Mahir<br>
<br>
<div class="moz-cite-prefix">On 07/15/2016 12:47 PM, Manohar Vanga
wrote:<br>
</div>
<blockquote
cite="mid:CAEktxaFkCippWcUWGYiU1OSEzUQbqPwMtLBFRVhg8v9u0f8yow@mail.gmail.com"
type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Jul 15, 2016 at 10:56 AM,
Björn Brandenburg <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:bbb@mpi-sws.org"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:bbb@mpi-sws.org">bbb@mpi-sws.org</a></a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><span><br>
> On 15 Jul 2016, at 01:49, Roohollah <<a
moz-do-not-send="true"
href="mailto:roohollahamiri@u.boisestate.edu"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:roohollahamiri@u.boisestate.edu">roohollahamiri@u.boisestate.edu</a></a>>
wrote:<br>
><br>
> I am trying to compile liblitmus, the latest
version. But I am getting the following error:<br>
><br>
> src/migration.c:83:27: error: array subscript is
below array bounds [-Werror=array-bounds]<br>
><br>
> I am using Fedora 24, gcc-6.1.1 . Is there any one
know how to solve that problem?<br>
<br>
<br>
</span>Looks like there’s an out-of-bounds access in
Glenn’s domain parsing code.<br>
<br>
<a moz-do-not-send="true"
href="https://github.com/LITMUS-RT/liblitmus/blob/master/src/migration.c#L83"
rel="noreferrer" target="_blank">https://github.com/LITMUS-RT/liblitmus/blob/master/src/migration.c#L83</a><br>
<br>
However, Mahir recently patched that loop and changed one
of the indices. Perhaps the patch was incomplete?<br>
<br>
<a moz-do-not-send="true"
href="https://github.com/LITMUS-RT/liblitmus/commit/322eaadaa95b4f64f4102a9bc6aaa2237401ae41"
rel="noreferrer" target="_blank">https://github.com/LITMUS-RT/liblitmus/commit/322eaadaa95b4f64f4102a9bc6aaa2237401ae41</a><br>
<br>
Mahir, can you please look into this?<br>
</blockquote>
<div><br>
</div>
<div>The change is incorrect. It should be 8 because the
last chunk doesn't have a trailing comma. Consider the
following example:</div>
<div><br>
</div>
<div>buf="xxx,xxxxxxxx,xxxxxxxx"</div>
<div>We want to parse it backwards starting with the last 8
characters.</div>
<div>At line 67, "chunk_str = buf + len - 8" gives the
correct behavior (chunk_str = "xxxxxxxx").</div>
<div>
<div><span style="white-space:pre-wrap">"</span>chunk_str
= buf + len - 9" ends up giving (chunk_str =
",xxxxxxxx").</div>
</div>
<div><br>
</div>
<div>On the other hand, the exit condition in the do-while
loop is relying on out-of-bounds pointer arithmetic which
is undefined in the C standard. I'm guessing the warning
is something that was recently introduced in GCC.</div>
<div><br>
</div>
<div>The loop can just be rewritten as follows to avoid the
use of undefined behaviour (I leave the correct patching
to Mahir). Hopefully this removes the issue:</div>
<div><br>
</div>
<div>
<div> /* process LSB chunks first (at the end of the
str) and move backward */</div>
<div> chunk_str = buf + len;</div>
<div> i = 0;</div>
<div> do</div>
<div> {</div>
<div> unsigned long chunk;</div>
<div> chunk_str -= 9;</div>
<div> if(chunk_str < buf)</div>
<div> chunk_str = buf; /* when MSB mask is less
than 8 chars */</div>
<div> chunk = strtoul(chunk_str, NULL, 16);</div>
<div> while (chunk) {</div>
<div> int j = ffsl(chunk) - 1;</div>
<div> int x = i*32 + j;</div>
<div> CPU_SET_S(x, *sz, *set);</div>
<div> chunk &= ~(1ul << j);</div>
<div> }</div>
<div> i += 1;</div>
<div> } while(chunk_str > buf);</div>
</div>
</div>
<div><br>
</div>
<div>(Please do review this carefully though.) Thanks!</div>
</div>
</div>
</blockquote>
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