[Bug sanitizer/81021] stack-use-after-scope false positive error with exceptions

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81021

--- Comment #21 from Martin Liška <marxin at gcc dot gnu.org> ---
> The code uses user-level threads (makecontext/setcontext etc). It annotates
> the new stack during the switch, see for example
> https://github.com/scylladb/seastar/blob/master/core/thread.cc#L66.
> Supposedly it's correct, but perhaps something is missing.

Then it should be fine. Well, the patch you send just workaround the problem. I
will dig in.