Re: [PATCH v3 5/6] Initialize the mapping of KASan shadow memory

[Russell King - ARM Linux]

On Mon, Apr 02, 2018 at 02:08:13PM -0400, Nicolas Pitre wrote:
> On Mon, 2 Apr 2018, Abbott Liu wrote:
> 
> > index c79b829..20161e2 100644
> > --- a/arch/arm/kernel/head-common.S
> > +++ b/arch/arm/kernel/head-common.S
> > @@ -115,6 +115,9 @@ __mmap_switched:
> >  	str	r8, [r2]			@ Save atags pointer
> >  	cmp	r3, #0
> >  	strne	r10, [r3]			@ Save control register values
> > +#ifdef CONFIG_KASAN
> > +	bl	kasan_early_init
> > +#endif
> >  	mov	lr, #0
> >  	b	start_kernel
> >  ENDPROC(__mmap_switched)
> 
> Would be better if lr was cleared before calling kasan_early_init.

No.  The code is correct - please remember that "bl" writes to LR.

The point of clearing LR here is to ensure that start_kernel is called
with a zero link register, which it won't be if kasan_early_init is
moved after it.

-- 
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