[Bug sanitizer/85230] asan: false positives in kernel on allocas

[chefmax at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85230

--- Comment #7 from chefmax at gcc dot gnu.org ---
(In reply to Dmitry Vyukov from comment #6)
> Right!
> 
> Unpoisoning before restoring SP looks like a reasonable and simple solution
> to me. I don't see any potential downsides.
> 
> Do you mind submitting a fix for this?
> 
> Thanks

Sure, but it seems that it's not so simple as I thought... it can make some
time to cook a proper fix (although I can attach a dirty workaround for x86_64
here to unblock your progress on a kernel side).