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    <head>
      <base href="http://llvm.org/bugs/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - Thread sanitizer reports race condition with std::async"
   href="http://llvm.org/bugs/show_bug.cgi?id=18611">18611</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Thread sanitizer reports race condition with std::async
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>C++11
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>michi.henning@canonical.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=11936" name="attach_11936" title="Thread sanitizer output">attachment 11936</a> <a href="attachment.cgi?id=11936&action=edit" title="Thread sanitizer output">[details]</a></span>
Thread sanitizer output

I wasn't sure which category to best select for this, so I'm reporting this for
clang/c++11. Please let me know if that's the wrong classification.

Thread sanitizer reports a race condition for the following program:

#include <future>

void run() {}

int main()
{
    auto f = std::async(std::launch::async, [] { run(); });
    f.get();
}

It's not clear to me whether this is a genuine race or a problem with thread
sanitizer. I've attached the sanitizer output.

Program was compiled with

clang++ -g --std=c++11 -fsanitize=thread x.cpp

Version info:

Ubuntu clang version 3.3-16ubuntu1 (branches/release_33) (based on LLVM 3.3)
Target: x86_64-pc-linux-gnu
Thread model: posix</pre>
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