Re: [PATCH v8 1/5] kasan: support backing vmalloc space with real shadow memory

[Christophe Leroy]

Daniel Axtens <dja@xxxxxxxxxx> a ÃcritÂ:

> Hi,
>
> > >  	/*
> > >  	 * Find a place in the tree where VA potentially will be
> > >  	 * inserted, unless it is merged with its sibling/siblings.
> > > @@ -741,6 +752,10 @@ merge_or_add_vmap_area(struct vmap_area *va,
> > >  		if (sibling->va_end == va->va_start) {
> > >  			sibling->va_end = va->va_end;
> > >
> > > +			kasan_release_vmalloc(orig_start, orig_end,
> > > +					      sibling->va_start,
> > > +					      sibling->va_end);
> > > +
> > The same.
>
> The call to kasan_release_vmalloc() is a static inline no-op if
> CONFIG_KASAN_VMALLOC is not defined, which I thought was the preferred
> way to do things rather than sprinkling the code with ifdefs?
>
> The complier should be smart enough to eliminate all the
> orig_state/orig_end stuff at compile time because it can see that it's
> not used, so there's no cost in the binary.


Daniel,

You are entirely right in your way to do i, that's fully in line with  
Linux kernel codying style  
https://www.kernel.org/doc/html/latest/process/coding-style.html#conditional-compilation

Christophe