Description of problem:

When trying gdb-heap on firefox, got an invalid cast exception.

Version-Release number of selected component (if applicable):

firefox-3.6.12-1.fc14.x86_64
gdb-7.2-23.fc14.x86_64
gdb-heap-0.5-2.fc14.x86_64


How reproducible:

Every time


Steps to Reproduce:
1. Start up firefox, note the pid of the/usr/,lib64/firefox-3.6/firefox
2. Start up gdb with and attach to the appropriate process:
    PYTHONPATH=/usr/share/gdb-heap gdb
    python import heap
    attach 2057 # this will need to be pid for /usr/lib64/firefox-3.6/firefox
3. Attempt to print out heap info with:
   heap
  
Actual results:

Traceback (most recent call last):
  File "/usr/share/gdb-heap/heap/commands.py", line 34, in g
    return f(self, args, from_tty)
  File "/usr/share/gdb-heap/heap/commands.py", line 56, in invoke
    usage_list = list(iter_usage_with_progress())
  File "/usr/share/gdb-heap/heap/__init__.py", line 526, in next
    return self.inner.next()
  File "/usr/share/gdb-heap/heap/__init__.py", line 550, in iter_usage
    for chunk in ms.iter_sbrk_chunks():
  File "/usr/share/gdb-heap/heap/glibc.py", line 239, in iter_sbrk_chunks
    if chunk.as_address() > 0:
  File "/usr/share/gdb-heap/heap/__init__.py", line 125, in as_address
    return long(self._gdbval.cast(type_void_ptr))
RuntimeError: Invalid cast.
Error occurred in Python command: Invalid cast.

Expected results:

Information about the various heap allocations that firefox is using.

Additional info: