Re: [PATCH v26 00/10] Simple Donor Migration for Proxy Execution

Peter Zijlstra
2026-03-27T15:21:22Z

On Fri, Mar 27, 2026 at 07:03:19PM +0530, K Prateek Nayak wrote:

> So John originally had that and then I saw Dan's comment in
> cleanup.h that reads:
>
> Lastly, given that the benefit of cleanup helpers is removal of
> "goto", and that the "goto" statement can jump between scopes, the
> expectation is that usage of "goto" and cleanup helpers is never
> mixed in the same function. I.e. for a given routine, convert all
> resources that need a "goto" cleanup to scope-based cleanup, or
> convert none of them.
>
> which can either be interpreted as "Don't do it unless you know what
> you are doing" or "There is at least one compiler that will get a
> goto + cleanup guard wrong" and to err on side of caution, I
> suggested we do break + enums.
>
> If there are no concerns, then the suggested diff is indeed much
> better.

IIRC the concern was doing partial error handling conversions and
getting it hopelessly wrong.

And while some GCC's generate wrong code when you goto into a guard, all
clangs ever will error on that, so any such code should not survive the
robots.

And then there was an issue with computed gotos and asm_goto, but I the
former are exceedingly rare (and again, clang will error IIRC) and the
latter we upped the minimum clang version for.

Anyway, there is nothing inherently wrong with using goto to exit a
scope and it works well.