ping: [patch] Detect infinite backtraces

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Tue, 21 Jan 2014 17:26:51 +0100, Jan Kratochvil wrote:
> To make a summary what can remain from this patch to get it accepted:
>  * "__morestack" check is forbidden
>  * frames ordering by $sp0 < $sp1 is forbidden
>  * dynamicsizehash.[ch] is forbidden
>  * only $sp0 == $sp1 can be checked and >= 2 frames loops are not detected
>  * therefore signal frames / sigaltstack makes no difference for this patch
>  * CFA check is forbidden, it should check real ebl-supplied SP

There is remaining this issue of the elfutils unwinder.

It seems a proper fix catching all infinite backtraces is not possible under
the constraints for the patch acceptance from this mail thread so asking for
verification if the constraints above which I deducted from the mail thread
are the ones required for the patch acceptance so one can write down at least
a partial fix of the problem.


Thanks,
Jan