Weird startup issue with -fsplit-stack

[Dmitry Antipov]

On 05/21/2014 06:10 PM, Ian Lance Taylor wrote:

> I'm sorry, I have nothing useful to suggest.  I agree that that sounds
> like a stack overflow, which should in general be impossible with
> -fsplit-stack when using the gold linker.  I don't know what is
> happening here.  I've tested with massive recursion so I don't think
> that is the problem by itself.

Hm...did you test with a lot of longjmps? I'm just curious about this
comment in libgcc/generic-morestack.c:

/* The stack segment that we think we are currently using.  This will
    be correct in normal usage, but will be incorrect if an exception
    unwinds into a different stack segment or if longjmp jumps to a
    different stack segment.  */

So, what happens if longjmp jumps to a different segment? Is the result
undefined? Is it possible to detect such a jump?

Dmitry