Re: [Boost-bugs] [Boost C++ Libraries] #4452: NDEBUG causes segv in interprocess::managed_mapped_file

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #4452: NDEBUG causes segv in interprocess::managed_mapped_file
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-07-02 16:24:00

#4452: NDEBUG causes segv in interprocess::managed_mapped_file
---------------------------------------------------------+------------------
  Reporter:  Richard Murphy <richard.murphy@…>           |       Owner:  igaztanaga              
      Type:  Bugs                                        |      Status:  reopened                
 Milestone:  Boost 1.48.0                                |   Component:  interprocess            
   Version:  Boost 1.46.1                                |    Severity:  Problem                 
Resolution:                                              |    Keywords:  NDEBUG interprocess segv
---------------------------------------------------------+------------------
Changes (by Lénaïc Huard <lhuard@…>):

  * status:  closed => reopened
  * version:  Boost 1.43.0 => Boost 1.46.1
  * resolution:  invalid =>
  * milestone:  Boost 1.44.0 => Boost 1.48.0

Comment:

 I have exactly the same problem with Boost 1.46.1 and even managed to
 reproduce it with a smaller program.

 Here is the code that reproduces the issue:

 {{{
 #include <cstdlib>
 #include <boost/interprocess/managed_shared_memory.hpp>

 int main()
 {
         boost::interprocess::managed_shared_memory aShm(
 boost::interprocess::create_only, "/toto", 4096 );
         return EXIT_SUCCESS;
 }
 }}}

 In my case, this piece of code works when compiled with g++ 4.4.
 But this program segvs when compiled:
 * with g++ 4.5 or g++ 4.6;
 * with `-DNDEBUG` (this is really what triggers the bug);
 * with optimizations enabled. `-O1` is enough.

 I had a look at that and managed to have the above program work with
 `g++-4.6 -O1 -DNDEBUG` by one patch on
 `intrusive/detail/tree_algorithms.hpp`:

 {{{
 --- /usr/include/boost/intrusive/detail/tree_algorithms.hpp     2011-06-12
 08:15:00.000000000 +0200
 +++ boost_patch/include/boost/intrusive/detail/tree_algorithms.hpp
 2011-07-02 18:09:02.504756424 +0200
 @@ -902,6 +902,7 @@
     {
        //Check if commit_data has not been initialized by a
 insert_unique_check call.
        BOOST_INTRUSIVE_INVARIANT_ASSERT(commit_data.node != 0);
 +      ((commit_data.node != 0) ? static_cast<void> (0) : abort());
        node_ptr parent_node(commit_data.node);
        if(parent_node == header){
           NodeTraits::set_parent(header, new_node);
 }}}

 This patch makes the above program works when compiled with `-O1` but is
 not enough for higher level of optimizations. With `-O2` and above and the
 above patch, the program keeps on segfaulting.

 This is obviously not an acceptable patch and I need to better understand
 the issue, but I hope this gives a clue.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4452#comment:2>
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