Re: [PATCH v3 1/2] arm64: Improve kernel address detection of __is_lm_address()

From: Catalin Marinas
Date: Fri Jan 22 2021 - 09:51:57 EST


On Fri, Jan 22, 2021 at 02:37:47PM +0000, Vincenzo Frascino wrote:
> Currently, the __is_lm_address() check just masks out the top 12 bits
> of the address, but if they are 0, it still yields a true result.
> This has as a side effect that virt_addr_valid() returns true even for
> invalid virtual addresses (e.g. 0x0).
>
> Improve the detection checking that it's actually a kernel address
> starting at PAGE_OFFSET.
>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>

Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>

The question is whether we leave this for 5.12 or we merge it earlier.

--
Catalin