From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
Mark Rutland <mark.rutland@arm.com>
Cc: catalin.marinas@arm.com, kernel-team@android.com,
Will Deacon <will@kernel.org>,
pasha.tatashin@soleen.com, james.morse@arm.com
Subject: Re: [PATCH] arm64: kexec: use __pa_symbol(empty_zero_page)
Date: Thu, 2 Dec 2021 10:59:26 +0000 [thread overview]
Message-ID: <163844023361.25776.13598404333751499994.b4-ty@kernel.org> (raw)
In-Reply-To: <20211130121849.3319010-1-mark.rutland@arm.com>
On Tue, 30 Nov 2021 12:18:49 +0000, Mark Rutland wrote:
> In machine_kexec_post_load() we use __pa() on `empty_zero_page`, so that
> we can use the physical address during arm64_relocate_new_kernel() to
> switch TTBR1 to a new set of tables. While `empty_zero_page` is part of
> the old kernel, we won't clobber it until after this switch, so using it
> is benign.
>
> However, `empty_zero_page` is part of the kernel image rather than a
> linear map address, so it is not correct to use __pa(x), and we should
> instead use __pa_symbol(x) or __pa(lm_alias(x)). Otherwise, when the
> kernel is built with DEBUG_VIRTUAL, we'll encounter splats as below, as
> I've seen when fuzzing v5.16-rc3 with Syzkaller:
>
> [...]
Applied to arm64 (for-next/fixes), thanks!
[1/1] arm64: kexec: use __pa_symbol(empty_zero_page)
https://git.kernel.org/arm64/c/2f2183243f52
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
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prev parent reply other threads:[~2021-12-02 11:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-30 12:18 [PATCH] arm64: kexec: use __pa_symbol(empty_zero_page) Mark Rutland
2021-11-30 17:02 ` Pasha Tatashin
2021-12-02 10:59 ` Will Deacon [this message]
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