linux-kernel - Re: [PATCH v3 1/2] arm64: Improve kernel address detection of __is_lm

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Date:   Fri, 22 Jan 2021 14:49:58 +0000
From:   Catalin Marinas <catalin.marinas@....com>
To:     Vincenzo Frascino <vincenzo.frascino@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kasan-dev@...glegroups.com,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Leon Romanovsky <leonro@...lanox.com>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Naresh Kamboju <naresh.kamboju@...aro.org>
Subject: Re: [PATCH v3 1/2] arm64: Improve kernel address detection of
 __is_lm_address()

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@....com>
> Cc: Will Deacon <will@...nel.org>
> Suggested-by: Catalin Marinas <catalin.marinas@....com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@....com>

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

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

-- 
Catalin