[RFC] Detect loops in the solib chain

[Stan Shebs]

Daniel Jacobowitz wrote:
> A MontaVista customer had a very interestingly corrupt core file -
> there was a stray pointer in the list of loaded shared libraries.  But
> it pointed to something which looked enough like a shared library
> entry to get by, and the bad entry's l_next pointed back at the
> corrupted entry that led to it.  So around and around we went, adding
> the same two libraries to the list.  When the solib chain reached
> about 2GB, GDB was killed.
>
> The best I could think of was to detect cycles.  It's a linked list
> that we're walking, so without cycles we're bounded by the amount of
> memory in the debuggee; it's by no means foolproof, but this should
> prevent more cases of wandering off into the woods than we do now.
>
> Does this look OK?  Tested on x86_64-linux, no regressions.
>   
What, no test case? :-) Anyway, it looks OK to me.

(You could make a little script to scribble on the executable...)

Stan