[PATCH] arm64: kasan: fix page_alloc tagging with DEBUG_VIRTUAL

[Catalin Marinas]

On Mon, Mar 08, 2021 at 05:10:23PM +0100, Andrey Konovalov wrote:
> When CONFIG_DEBUG_VIRTUAL is enabled, the default page_to_virt() macro
> implementation from include/linux/mm.h is used. That definition doesn't
> account for KASAN tags, which leads to no tags on page_alloc allocations.
> 
> Provide an arm64-specific definition for page_to_virt() when
> CONFIG_DEBUG_VIRTUAL is enabled that takes care of KASAN tags.
> 
> Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
> Cc: <stable at vger.kernel.org>
> Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
> ---
>  arch/arm64/include/asm/memory.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index c759faf7a1ff..0aabc3be9a75 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -328,6 +328,11 @@ static inline void *phys_to_virt(phys_addr_t x)
>  #define ARCH_PFN_OFFSET		((unsigned long)PHYS_PFN_OFFSET)
>  
>  #if !defined(CONFIG_SPARSEMEM_VMEMMAP) || defined(CONFIG_DEBUG_VIRTUAL)
> +#define page_to_virt(x)	({						\
> +	__typeof__(x) __page = x;					\
> +	void *__addr = __va(page_to_phys(__page));			\
> +	(void *)__tag_set((const void *)__addr, page_kasan_tag(__page));\
> +})
>  #define virt_to_page(x)		pfn_to_page(virt_to_pfn(x))

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>