linux-kernel - Re: [PATCH v2] arm64/kdump: pass dm-crypt keys to kdump kernel

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Message-ID: <20260106-mammoth-of-wondrous-blizzard-e30d62@quoll>
Date: Tue, 6 Jan 2026 09:05:49 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Coiby Xu <coxu@...hat.com>
Cc: kexec@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, 
	Arnaud Lefebvre <arnaud.lefebvre@...ver-cloud.com>, Baoquan he <bhe@...hat.com>, Dave Young <dyoung@...hat.com>, 
	Kairui Song <ryncsn@...il.com>, Pingfan Liu <kernelfans@...il.com>, 
	Andrew Morton <akpm@...ux-foundation.org>, Catalin Marinas <catalin.marinas@....com>, 
	Will Deacon <will@...nel.org>, Rob Herring <robh@...nel.org>, 
	Saravana Kannan <saravanak@...nel.org>, open list <linux-kernel@...r.kernel.org>, 
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v2] arm64/kdump: pass dm-crypt keys to kdump kernel

On Tue, Jan 06, 2026 at 02:22:30PM +0800, Coiby Xu wrote:
> CONFIG_CRASH_DM_CRYPT has been introduced to support LUKS-encrypted
> device dump target by addressing two challenges [1],
>  - Kdump kernel may not be able to decrypt the LUKS partition. For some
>    machines, a system administrator may not have a chance to enter the
>    password to decrypt the device in kdump initramfs after the 1st kernel
>    crashes
> 
>  - LUKS2 by default use the memory-hard Argon2 key derivation function
>    which is quite memory-consuming compared to the limited memory reserved
>    for kdump.
> 
> To also enable this feature for ARM64, we only need to add device tree
> property dmcryptkeys [2] as similar to elfcorehdr to pass the memory
> address of the stored info of dm-crypt keys to the kdump kernel.
> 
> [1] https://lore.kernel.org/all/20250502011246.99238-1-coxu@redhat.com/
> [2] https://github.com/devicetree-org/dt-schema/pull/181
> 
> Cc: Arnaud Lefebvre <arnaud.lefebvre@...ver-cloud.com>
> Cc: Baoquan he <bhe@...hat.com>
> Cc: Dave Young <dyoung@...hat.com>
> Cc: Kairui Song <ryncsn@...il.com>
> Cc: Pingfan Liu <kernelfans@...il.com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Krzysztof Kozlowski <krzk@...nel.org>
> Signed-off-by: Coiby Xu <coxu@...hat.com>
> ---
> v2
> - Krzysztof
>   - Use imperative mood for commit message
>   - Add dt-schema ABI Documentation
> - Don't print dm-crypt keys address via pr_debug

Your changelog should explicitly document that this has external
dependency on dtschema pull request, so that maintainers know that.

Also, in the future:
Do not attach (thread) your patchsets to some other threads (unrelated
or older versions). This buries them deep in the mailbox and might
interfere with applying entire sets. See also:
https://elixir.bootlin.com/linux/v6.16-rc2/source/Documentation/process/submitting-patches.rst#L830

Best regards,
Krzysztof