Boost C++ Libraries: Ticket #4452: NDEBUG causes segv in interprocess::managed_mapped_file

attachment set

Mon, 19 Jul 2010 10:41:15 GMT

attachment → boost-interprocess-bug-report.cpp

status changed; resolution set

Ion Gaztañaga — Fri, 01 Apr 2011 18:55:19 GMT

status new → closed
resolution → invalid

I could not reproduce the bug, I close this as wontfix and reopen it if the bug is reported by another user.

status, version, milestone changed; resolution deleted

Sat, 02 Jul 2011 16:24:00 GMT

status closed → reopened
version Boost 1.43.0 → Boost 1.46.1
resolution invalid
milestone Boost 1.44.0 → Boost 1.48.0

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.

clint@… — Wed, 09 Nov 2011 14:19:30 GMT

I've noticed in gcc 4.5.0 that passing the -fno-tree-pta seems to clear up the issue on all optimization levels.

There is a known issue with pointer analysis in 4.5.0 that this specific fix may be related to.

anonymous — Wed, 09 Nov 2011 16:52:04 GMT

Replying to clint@…:

I've noticed in gcc 4.5.0 that passing the -fno-tree-pta seems to clear up the issue on all optimization levels.

There is a known issue with pointer analysis in 4.5.0 that this specific fix may be related to.

Upon further investigation, this work around doesn't actually solve the problem. Instead, it merely delayed the segmentation fault for my use case.

status changed; resolution set

Ion Gaztañaga — Sat, 24 Dec 2011 11:05:56 GMT

status reopened → closed
resolution → fixed

This was fixed in Boost 1.48 marking offset_ptr operations as non-inlineable.