[PATCH] arm64: kasan: fix phys_to_virt() false positive on tag-based kasan

Will Deacon will at kernel.org
Mon Aug 19 05:56:26 PDT 2019


On Mon, Aug 19, 2019 at 07:44:20PM +0800, Walter Wu wrote:
> __arm_v7s_unmap() call iopte_deref() to translate pyh_to_virt address,
> but it will modify pointer tag into 0xff, so there is a false positive.
> 
> When enable tag-based kasan, phys_to_virt() function need to rewrite
> its original pointer tag in order to avoid kasan report an incorrect
> memory corruption.

Hmm. Which tree did you see this on? We've recently queued a load of fixes
in this area, but I /thought/ they were only needed after the support for
52-bit virtual addressing in the kernel.

Will



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