Re: [PATCH v4 5/5] arm64: Kconfig: select KASAN_VMALLOC if KANSAN_GENERIC is enabled

[Lecopzer Chen]

> On Wed, Mar 24, 2021 at 12:05:22PM +0800, Lecopzer Chen wrote:
> > Before this patch, someone who wants to use VMAP_STACK when
> > KASAN_GENERIC enabled must explicitly select KASAN_VMALLOC.
> > 
> > From Will's suggestion [1]:
> >   > I would _really_ like to move to VMAP stack unconditionally, and
> >   > that would effectively force KASAN_VMALLOC to be set if KASAN is in use
> > 
> > Because VMAP_STACK now depends on either HW_TAGS or KASAN_VMALLOC if
> > KASAN enabled, in order to make VMAP_STACK selected unconditionally,
> > we bind KANSAN_GENERIC and KASAN_VMALLOC together.
> > 
> > Note that SW_TAGS supports neither VMAP_STACK nor KASAN_VMALLOC now,
> > so this is the first step to make VMAP_STACK selected unconditionally.
> 
> Do you know if anybody is working on this? It's really unfortunate that
> we can't move exclusively to VMAP_STACK just because of SW_TAGS KASAN.
> 
> That said, what is there to do? As things stand, won't kernel stack
> addresses end up using KASAN_TAG_KERNEL?


Hi Andrey,

Do you or any KASAN developers have already had any plan for this?



thanks,
Lecopzer