Re: [Libmesh-users] A strange seg fault error

[Roy S. <roy...@ic...>]

That's pretty baffling.  We construct a singleton RemoteElem object
(which like any other new Elem should get a NULL _children member),
then when it's time to destruct it, _children is non-NULL?

I've no idea how this could happen (especially in such a way that it
wouldn't affect *everyone*).  The only thing I can think of to do with
debugging it is to step through the program and figure out where that
remote_elem->_children pointer gets set non-NULL.  Unfortunately that
wouldn't be a very fun process, and it's not one that we can help you
much with since we can't replicate the problem.
---
Roy


On Tue, 6 Aug 2013, Andrew Davis wrote:

> Hey,
> 
> Thanks!  Yes rebuilding with gdb helps with the backtrace information.  Now when I run the same program I still get
> a seg. fault but the backtrace info in gdb is
> 
> #0  __GI___libc_free (mem=0x1) at malloc.c:2968
> #1  0x000000000046219c in libMesh::Elem::~Elem (this=0x6c11e0, __in_chrg=<optimized out>) at
> /scratch1/local/include/libmesh/elem.h:1336
> #2  0x00007ffff6b701ca in libMesh::RemoteElem::~RemoteElem (this=0x6c11e0, __in_chrg=<optimized out>) at
> src/geom/remote_elem.C:60
> #3  0x00007ffff6b70236 in libMesh::RemoteElem::~RemoteElem (this=0x6c11e0, __in_chrg=<optimized out>) at
> src/geom/remote_elem.C:65
> #4  0x00007ffff67e1bf9 in libMesh::Singleton::cleanup () at src/base/libmesh_singleton.C:108
> #5  0x00007ffff67c2542 in libMesh::LibMeshInit::~LibMeshInit (this=0x7fffffffe100, __in_chrg=<optimized out>) at
> src/base/libmesh.C:548
> #6  0x0000000000457a2f in main (argc=1, argv=0x7fffffffe238) at
> /scratch1/davisad/software/muq-ice/modules/RunTests.cpp:18
> 
> Is this more informative to you?
> 
> Thanks,
> Andrew
> 
> 
> On Tue, Aug 6, 2013 at 3:01 PM, Roy Stogner <roy...@ic...> wrote:
>
>       Start by building (or rebuilding just your test program) in debug
>       mode; if you're using opt then it's nearly impossible to pull helpful
>       information out of gdb.
>       ---
>       Roy
> 
> 
> 
>