Crash in `i frame'

[Richard Stallman]

In GDB 6.4 on GNU/Linux, I did `i frame' after a strange Emacs crash
involving stack clobberage.  The command did not work, reporting
"internal error" in dwarf-frame2.c:676.  (I am typing this from
memory; I can't be sure of the file name, but the line number was
definitely 676.)

The selected frame was the innermost one, and was calling
__kernel_vsyscall (that may not be the precise spelling).

`i frame' is a low-level command for last resort examination of the
stack, in comfusing cases.  It must be written defensively, so that it
_always_ works, no matter how unreasonable the data is.  It must never
report "internal error"; it must do something reasonable, no matter
what data it finds.

Please ack when this is fixed -- it is very important.