GDB Frame Filter - handling corrupt stack

Simeon S
Tue Sep 9 12:26:00 GMT 2014

Hi all,

I am trying to decorate the output of "backtrace" command. I have
written a simple gdb Frame Filter coupled with a Frame Decorator. I
have followed the official documentation tutorial
My gdb is compiled against Python 3.3.2 and my code looks like this:

    import gdb
    import itertools
    from gdb.FrameDecorator import FrameDecorator
    import copy

    class UpperCase_Decorator (FrameDecorator):
        def __init__(self, fobj):
            super(UpperCase_Decorator, self).__init__(fobj)
            self.fobj = fobj

        def function(self):
            frame = self.fobj.inferior_frame()

            if not frame.is_valid():
                return ""

            name = str(
            return name

    class InlineFilter():
        def __init__(self):
   = "InlinedFrameFilter"
            self.priority = 100
            self.enabled = True
            gdb.frame_filters[] = self

        def filter(self, frame_iter):
            frame_iter = map(UpperCase_Decorator,
            return frame_iter

    ff = InlineFilter()

When the gdb "backtrace" command is issued, frames are decorated
followed by a gdb crash. This is what the last output from gdb is:

    UNIX ERR:tcsetattr:Input/output error
    Segmentation fault (core dumped)

The stack seems to be corrupt which is what I suspect is causing the
crash. If the frame filter is disabled, the last line of the
"backtrace" command is:

    Backtrace stopped: previous frame inner to this frame (corrupt stack?)

I haven't looked into why the stack is corrupt - all the frames of
interest to me are there.  Is there a way to catch this condition to
avoid crashing? I am not interested in any of the corrupt frames -
what is in the stack is enough.

I guess I am looking for a mechanism to stop gdb iterating over
further frames if it detects a corrupt/invalid frame.  The
documentation does say that gdb has to iterate over all stack frames


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