[Bug libstdc++/34095] New: parallel mode: segfault in std::sort

["bangerth at dealii dot org" <gcc-bugzilla at gcc dot gnu dot org>]

I tried to figure out what is going on here, but it's getting
to complicated in the libstdc++ innards for me to spot the problem.
In any case, this little program
-------------------
#include <vector>
#include <algorithm>

struct S
{
    unsigned int line;
    std::vector<double> entries;

    bool operator < (const S &a) const
      {
        return line < a.line;
      }      
};


int main () 
{
  std::vector<S> lines(20000);  
  std::sort (lines.begin(), lines.end());
}
------------------------
produces a segfault for me when compiled with parallel mode.

A backtrace is here:
(gdb) bt
#0  0x0805cf59 in ~vector (this=0xb6439ffc)
    at
/tmp/bangerth/bin/gcc-mainline/lib/gcc/i686-pc-linux-gnu/4.3.0/../../../../include/c++/4.3.0/bits/stl_vector.h:304
#1  0x0805cf9d in ~S (this=0xb6439ff8) at step-14.cc:5
#2  0x0806d1b9 in
__gnu_parallel::parallel_sort_mwms_pu<__gnu_cxx::__normal_iterator<S*,
std::__cxx1998::vector<S, std::allocator<S> > >, std::less<S> > (
    d=0x807722c, comp=@0xbfffd498)
    at
/tmp/bangerth/bin/gcc-mainline/lib/gcc/i686-pc-linux-gnu/4.3.0/../../../../include/c++/4.3.0/parallel/multiway_mergesort.h:312
#3  0x08057c73 in
__gnu_parallel::parallel_sort_mwms<__gnu_cxx::__normal_iterator<S*,
std::__cxx1998::vector<S, std::allocator<S> > >, std::less<S> > (
    .omp_data_i=0xbfffd450)
    at
/tmp/bangerth/bin/gcc-mainline/lib/gcc/i686-pc-linux-gnu/4.3.0/../../../../include/c++/4.3.0/parallel/multiway_mergesort.h:391
#4  0xb6dd03e0 in gomp_thread_start (xdata=0xbfffd330)
    at ../../../svn/libgomp/team.c:108
#5  0xb6db2aa7 in start_thread () from /lib/tls/libpthread.so.0

This is in the worker thread, not the main thread from which it was spawned.

Hope this helps, cheers
 W.


-- 
           Summary: parallel mode: segfault in std::sort
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bangerth at dealii dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34095