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    SubjectRe: [PATCH mm v3 23/38] kasan, arm64: reset pointer tags of vmapped stacks
    On Mon, Dec 13, 2021 at 10:54:19PM +0100, andrey.konovalov@linux.dev wrote:
    > From: Andrey Konovalov <andreyknvl@google.com>
    >
    > Once tag-based KASAN modes start tagging vmalloc() allocations,
    > kernel stacks start getting tagged if CONFIG_VMAP_STACK is enabled.
    >
    > Reset the tag of kernel stack pointers after allocation in
    > arch_alloc_vmap_stack().
    >
    > For SW_TAGS KASAN, when CONFIG_KASAN_STACK is enabled, the
    > instrumentation can't handle the SP register being tagged.
    >
    > For HW_TAGS KASAN, there's no instrumentation-related issues. However,
    > the impact of having a tagged SP register needs to be properly evaluated,
    > so keep it non-tagged for now.
    >
    > Note, that the memory for the stack allocation still gets tagged to
    > catch vmalloc-into-stack out-of-bounds accesses.
    >
    > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

    Acked-by: Catalin Marinas <catalin.marinas@arm.com>

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