Re: feature/asan-gc-poisoning aa9ca2c1493 2/2: src/alloc.c: Fix incorrect pointer arithmetic.

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: Vibhav Pant <vibhavp@gmail.com>
> Date: Mon, 05 Dec 2022 09:13:59 +0800
> 
> Vibhav Pant <vibhavp@gmail.com> writes:
> 
> > branch: feature/asan-gc-poisoning
> > commit aa9ca2c1493f1cd9d50698747fd054b1be53dc95
> > Author: Vibhav Pant <vibhavp@gmail.com>
> > Commit: Vibhav Pant <vibhavp@gmail.com>
> >
> >     src/alloc.c: Fix incorrect pointer arithmetic.
> >     
> >     * src/alloc.c (live_float_holding): Use parenthesis around the
> >     pointer arithmetic expression to untag 'cp' correctly.
> > ---
> >  src/alloc.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/src/alloc.c b/src/alloc.c
> > index 31108837e5a..6b8a4cdcc02 100644
> > --- a/src/alloc.c
> > +++ b/src/alloc.c
> > @@ -5104,7 +5104,7 @@ live_float_holding (struct mem_node *m, void *p)
> >       && (b != float_block
> >           || offset / sizeof b->floats[0] < float_block_index))
> >     {
> > -     struct Lisp_Float *f = (struct Lisp_Float *) cp - off;
> > +     struct Lisp_Float *f = (struct Lisp_Float *) (cp - off);
> >  #if GC_ASAN_POISON_OBJECTS
> >       if (__asan_region_is_poisoned (f, sizeof (*f)))
> >         return NULL;
> 
> This is a problem on master and emacs-29 too, right?

I don't think so: there are no such code on those two branches, AFAICT.