matplotlib-users

[Matplotlib-users] Segmentation fault from inside transforms

[Ted D. <ted...@jp...>]

I'm trying to build matplotlib and I'm getting a segmentation fault when I do:

from matplotlib import *

I've traced the fault down to the transforms module.

My first attempt used:
gcc 3.3.2
Python 2.3.3
numarray 1.1
gdmodule 0.52
gd 2.0.28
freetype 2.1.9
agg 22
matplotlib 0.63.4

In this version _na_transform segementation faults at this line:
   static _transforms_module* _transforms = new _transforms_module;

I traced the fault down to the ExtensionModuleBaseClass where it attempts 
to call:  __Py_PackageContext()

It looks to me like this function is trying to access the variable (which 
it dereferences WITHOUT checking for a null pointer).
static char **ptr__Py_PackageContext = NULL;

This ptr gets init'ed in the function InitialisePythonIndirectInterface() 
but I can't find anywhere that function is being called.

FYI: I also tried matplotlib 0.62.4 and I get the same error.

Can anybody figure out what's happening to me?
Thanks,
Ted

Re: [Matplotlib-users] Segmentation fault from inside transforms

[John H. <jdh...@ac...>]

>>>>> "Ted" == Ted Drain <ted...@jp...> writes:

    Ted> I'm trying to build matplotlib and I'm getting a segmentation
    Ted> fault when I do: from matplotlib import *

    Ted> I've traced the fault down to the transforms module.

    Ted> My first attempt used: gcc 3.3.2 Python 2.3.3 numarray 1.1
    Ted> gdmodule 0.52 gd 2.0.28 freetype 2.1.9 agg 22 matplotlib
    Ted> 0.63.4

Standard issue stuff - very close to what most people are using w/o
incident.  Hmmmm....

    Ted> In this version _na_transform segementation faults at this
    Ted> line: static _transforms_module* _transforms = new
    Ted> _transforms_module;

    Ted> I traced the fault down to the ExtensionModuleBaseClass where
    Ted> it attempts to call: __Py_PackageContext()

    Ted> It looks to me like this function is trying to access the
    Ted> variable (which it dereferences WITHOUT checking for a null
    Ted> pointer).  static char **ptr__Py_PackageContext = NULL;

Could you try editing it an adding the NULL test; if this works can
you submit a patch pack to be and a bug report to the pycxx sf site?

    Ted> This ptr gets init'ed in the function
    Ted> InitialisePythonIndirectInterface() but I can't find anywhere
    Ted> that function is being called.

    Ted> FYI: I also tried matplotlib 0.62.4 and I get the same error.

It couldn't be the exact same error, because _na_transforms did not
exist in 0.62.4.  Do you mean that you got a segfault on the same line
in _transform?

Thanks,
JDH

Re: [Matplotlib-users] Segmentation fault from inside transforms

[Ted D. <ted...@jp...>]

>It couldn't be the exact same error, because _na_transforms did not
>exist in 0.62.4.  Do you mean that you got a segfault on the same line
>in _transform?

Sorry - that's what I meant.  It looks like I was a little mistaken.  I 
didn't realize that there are 2 versions of __Py_PackageContext() in the 
same file.  I was orginally looking at the Windows version (I'm building on 
linux).

However, if the linux version looks like this (unmodified):

char *__Py_PackageContext()     { return _Py_PackageContext; }

I get a segmentation fault at the return line.

I then added a print statement to it:

char *__Py_PackageContext()
{
    std::cerr << "context 0\n";
    return _Py_PackageContext;
}

and then everything works!  Off the top of my head, it might be a case of 
C++ static object initialization problems but I can't find any obvious 
places that might be happening.

Ted

At 01:00 PM 10/21/2004, John Hunter wrote:
> >>>>> "Ted" == Ted Drain <ted...@jp...> writes:
>
>     Ted> I'm trying to build matplotlib and I'm getting a segmentation
>     Ted> fault when I do: from matplotlib import *
>
>     Ted> I've traced the fault down to the transforms module.
>
>     Ted> My first attempt used: gcc 3.3.2 Python 2.3.3 numarray 1.1
>     Ted> gdmodule 0.52 gd 2.0.28 freetype 2.1.9 agg 22 matplotlib
>     Ted> 0.63.4
>
>Standard issue stuff - very close to what most people are using w/o
>incident.  Hmmmm....
>
>     Ted> In this version _na_transform segementation faults at this
>     Ted> line: static _transforms_module* _transforms = new
>     Ted> _transforms_module;
>
>     Ted> I traced the fault down to the ExtensionModuleBaseClass where
>     Ted> it attempts to call: __Py_PackageContext()
>
>     Ted> It looks to me like this function is trying to access the
>     Ted> variable (which it dereferences WITHOUT checking for a null
>     Ted> pointer).  static char **ptr__Py_PackageContext = NULL;
>
>Could you try editing it an adding the NULL test; if this works can
>you submit a patch pack to be and a bug report to the pycxx sf site?
>
>     Ted> This ptr gets init'ed in the function
>     Ted> InitialisePythonIndirectInterface() but I can't find anywhere
>     Ted> that function is being called.
>
>     Ted> FYI: I also tried matplotlib 0.62.4 and I get the same error.
>
>It couldn't be the exact same error, because _na_transforms did not
>exist in 0.62.4.  Do you mean that you got a segfault on the same line
>in _transform?
>
>Thanks,
>JDH

Re: [Matplotlib-users] Segmentation fault from inside transforms

[Todd M. <jm...@st...>]

On Thu, 2004-10-21 at 16:00, John Hunter wrote:
> >>>>> "Ted" == Ted Drain <ted...@jp...> writes:
> 
>     Ted> I'm trying to build matplotlib and I'm getting a segmentation
>     Ted> fault when I do: from matplotlib import *
> 
>     Ted> I've traced the fault down to the transforms module.
> 
>     Ted> My first attempt used: gcc 3.3.2 Python 2.3.3 numarray 1.1
>     Ted> gdmodule 0.52 gd 2.0.28 freetype 2.1.9 agg 22 matplotlib
>     Ted> 0.63.4
> 
> Standard issue stuff - very close to what most people are using w/o
> incident.  Hmmmm....
> 
>     Ted> In this version _na_transform segementation faults at this
>     Ted> line: static _transforms_module* _transforms = new
>     Ted> _transforms_module;
> 
>     Ted> I traced the fault down to the ExtensionModuleBaseClass where
>     Ted> it attempts to call: __Py_PackageContext()
> 
>     Ted> It looks to me like this function is trying to access the
>     Ted> variable (which it dereferences WITHOUT checking for a null
>     Ted> pointer).  static char **ptr__Py_PackageContext = NULL;
> 
> Could you try editing it an adding the NULL test; if this works can
> you submit a patch pack to be and a bug report to the pycxx sf site?
> 
>     Ted> This ptr gets init'ed in the function
>     Ted> InitialisePythonIndirectInterface() but I can't find anywhere
>     Ted> that function is being called.
> 
>     Ted> FYI: I also tried matplotlib 0.62.4 and I get the same error.
> 
> It couldn't be the exact same error, because _na_transforms did not
> exist in 0.62.4.  Do you mean that you got a segfault on the same line
> in _transform?

Check for matplotlib/_transforms.so left over from prior installations
and blow away your old matplotlib and re-install if you find it.  Before
you re-install, also blow away matplotlib/build.

Todd

Re: [Matplotlib-users] Segmentation fault from inside transforms

[Ted D. <ted...@jp...>]

Well I have somewhat good news.  I was using an older machine (RedHat7) 
when I had these problems.  I went to a much newer redhat machine and 
everything works fine.  Same version of Python, gcc, etc - just a newer 
operating system.

I guess I'll just ignore this problem and stick with the newer machine.

Ted

At 01:47 PM 10/21/2004, Todd Miller wrote:
>On Thu, 2004-10-21 at 16:00, John Hunter wrote:
> > >>>>> "Ted" == Ted Drain <ted...@jp...> writes:
> >
> >     Ted> I'm trying to build matplotlib and I'm getting a segmentation
> >     Ted> fault when I do: from matplotlib import *
> >
> >     Ted> I've traced the fault down to the transforms module.
> >
> >     Ted> My first attempt used: gcc 3.3.2 Python 2.3.3 numarray 1.1
> >     Ted> gdmodule 0.52 gd 2.0.28 freetype 2.1.9 agg 22 matplotlib
> >     Ted> 0.63.4
> >
> > Standard issue stuff - very close to what most people are using w/o
> > incident.  Hmmmm....
> >
> >     Ted> In this version _na_transform segementation faults at this
> >     Ted> line: static _transforms_module* _transforms = new
> >     Ted> _transforms_module;
> >
> >     Ted> I traced the fault down to the ExtensionModuleBaseClass where
> >     Ted> it attempts to call: __Py_PackageContext()
> >
> >     Ted> It looks to me like this function is trying to access the
> >     Ted> variable (which it dereferences WITHOUT checking for a null
> >     Ted> pointer).  static char **ptr__Py_PackageContext = NULL;
> >
> > Could you try editing it an adding the NULL test; if this works can
> > you submit a patch pack to be and a bug report to the pycxx sf site?
> >
> >     Ted> This ptr gets init'ed in the function
> >     Ted> InitialisePythonIndirectInterface() but I can't find anywhere
> >     Ted> that function is being called.
> >
> >     Ted> FYI: I also tried matplotlib 0.62.4 and I get the same error.
> >
> > It couldn't be the exact same error, because _na_transforms did not
> > exist in 0.62.4.  Do you mean that you got a segfault on the same line
> > in _transform?
>
>Check for matplotlib/_transforms.so left over from prior installations
>and blow away your old matplotlib and re-install if you find it.  Before
>you re-install, also blow away matplotlib/build.
>
>Todd