[PATCH] Memory fencing problem in pthread cancellation

[Joseph S. Myers]

On Wed, 16 Jan 2013, Rich Felker wrote:

> I've seen that the unwinder goes to great lengths (I would call it
> "hideous hacks") for stuff related to signal trampolines, and as far
> as I can tell, the only reason it would ever be needed is for
> unwinding out of signal handlers, which is DEEP in the realm of UB and
> not something I can see any justification for trying to support. Is
> there another reason the signal trampolines need special consideration
> that I'm not seeing?

Unwinding is not just about things defined at language level such as C++ 
exceptions (and thread cancellation).  Accurate unwinding from signal 
handlers can be used for other things such as profiling (see the Froyd et 
al paper in the 2006 GCC Summit proceedings).

-- 
Joseph S. Myers
joseph@codesourcery.com