# What is unhandled Sigsegv

Hi,

I'm working with sage 4.7.2 on a virtual machine on windows 7. I have some more lines of code where I read some data tables and try to fit them with find_fit and than calculate confidence intervals. Suddenly I get and error of the following kind:

```
[...]
/home/sage/sage/local/lib/libpython2.6.so.1.0(PyRun_InteractiveLoopFlags\
+0x5b)[0xd1d8bb]
/home/sage/sage/local/lib/libpython2.6.so.1.0(PyRun_AnyFileExFlags+0x4e)\
[0xd1df3e]
/home/sage/sage/local/lib/libpython2.6.so.1.0(Py_Main+0xca0)[0xd2ce60]
/home/sage/sage/local/bin/python(main+0x27)[0x80485c7]
/lib/libc.so.6(__libc_start_main+0xe6)[0x126e36]
/home/sage/sage/local/bin/python[0x8048501]
------------------------------------------------------------------------
Unhandled SIGSEGV: A segmentation fault occurred in Sage.
This probably occurred because a *compiled* component of Sage has a bug
in it and is not properly wrapped with sig_on(), sig_off(). You might
want to run Sage under gdb with 'sage -gdb' to debug this.
Sage will now terminate.
------------------------------------------------------------------------
```

I found some a trac ticket concerning this but it does not help me. Also I do not know how to use the debugging command with the VM to give you further information or where to but the notebook and the data file so everyone could have a further look if wanted. Do not hesitate to ask for additional information. Again thanks in advance

Basically, the error message at the bottom means what it says - there was an error in something that was not just a Python file. If you the code you used and a link to the data files, or a (public) link to an offending .sws file, someone who understands compiled stuff can certainly help you. Keep in mind that since you're using a somewhat older version of Sage, this bug may have already been fixed (say, in 5.0.1).

Try to isolate a minimal testcase, ideally a single command that generates the segfault.