linux-kernel - Re: [PATCH v4 02/30] kho: make debugfs interface optional

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <mafs07bx8ouva.fsf@kernel.org>
Date: Mon, 06 Oct 2025 18:30:49 +0200
From: Pratyush Yadav <pratyush@...nel.org>
To: Pasha Tatashin <pasha.tatashin@...een.com>
Cc: pratyush@...nel.org,  jasonmiu@...gle.com,  graf@...zon.com,
  changyuanl@...gle.com,  rppt@...nel.org,  dmatlack@...gle.com,
  rientjes@...gle.com,  corbet@....net,  rdunlap@...radead.org,
  ilpo.jarvinen@...ux.intel.com,  kanie@...ux.alibaba.com,
  ojeda@...nel.org,  aliceryhl@...gle.com,  masahiroy@...nel.org,
  akpm@...ux-foundation.org,  tj@...nel.org,  yoann.congal@...le.fr,
  mmaurer@...gle.com,  roman.gushchin@...ux.dev,  chenridong@...wei.com,
  axboe@...nel.dk,  mark.rutland@....com,  jannh@...gle.com,
  vincent.guittot@...aro.org,  hannes@...xchg.org,
  dan.j.williams@...el.com,  david@...hat.com,  joel.granados@...nel.org,
  rostedt@...dmis.org,  anna.schumaker@...cle.com,  song@...nel.org,
  zhangguopeng@...inos.cn,  linux@...ssschuh.net,
  linux-kernel@...r.kernel.org,  linux-doc@...r.kernel.org,
  linux-mm@...ck.org,  gregkh@...uxfoundation.org,  tglx@...utronix.de,
  mingo@...hat.com,  bp@...en8.de,  dave.hansen@...ux.intel.com,
  x86@...nel.org,  hpa@...or.com,  rafael@...nel.org,  dakr@...nel.org,
  bartosz.golaszewski@...aro.org,  cw00.choi@...sung.com,
  myungjoo.ham@...sung.com,  yesanishhere@...il.com,
  Jonathan.Cameron@...wei.com,  quic_zijuhu@...cinc.com,
  aleksander.lobakin@...el.com,  ira.weiny@...el.com,
  andriy.shevchenko@...ux.intel.com,  leon@...nel.org,  lukas@...ner.de,
  bhelgaas@...gle.com,  wagi@...nel.org,  djeffery@...hat.com,
  stuart.w.hayes@...il.com,  lennart@...ttering.net,  brauner@...nel.org,
  linux-api@...r.kernel.org,  linux-fsdevel@...r.kernel.org,
  saeedm@...dia.com,  ajayachandra@...dia.com,  jgg@...dia.com,
  parav@...dia.com,  leonro@...dia.com,  witu@...dia.com,
  hughd@...gle.com,  skhawaja@...gle.com,  chrisl@...nel.org,
  steven.sistare@...cle.com
Subject: Re: [PATCH v4 02/30] kho: make debugfs interface optional

On Mon, Sep 29 2025, Pasha Tatashin wrote:

> Currently, KHO is controlled via debugfs interface, but once LUO is
> introduced, it can control KHO, and the debug interface becomes
> optional.
>
> Add a separate config CONFIG_KEXEC_HANDOVER_DEBUG that enables
> the debugfs interface, and allows to inspect the tree.
>
> Move all debugfs related code to a new file to keep the .c files
> clear of ifdefs.
>
> Co-developed-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@...een.com>
> ---
>  MAINTAINERS                      |   3 +-
>  kernel/Kconfig.kexec             |  10 ++
>  kernel/Makefile                  |   1 +
>  kernel/kexec_handover.c          | 255 +++++--------------------------
>  kernel/kexec_handover_debug.c    | 218 ++++++++++++++++++++++++++
>  kernel/kexec_handover_internal.h |  44 ++++++
>  6 files changed, 311 insertions(+), 220 deletions(-)
>  create mode 100644 kernel/kexec_handover_debug.c
>  create mode 100644 kernel/kexec_handover_internal.h
>
[...]
> --- a/kernel/Kconfig.kexec
> +++ b/kernel/Kconfig.kexec
> @@ -109,6 +109,16 @@ config KEXEC_HANDOVER
>  	  to keep data or state alive across the kexec. For this to work,
>  	  both source and target kernels need to have this option enabled.
>  
> +config KEXEC_HANDOVER_DEBUG

Nit: can we call it KEXEC_HANDOVER_DEBUGFS instead? I think we would
like to add a KEXEC_HANDOVER_DEBUG at some point to control debug
asserts for KHO, and the naming would get confusing. And renaming config
symbols is kind of a pain.

> +	bool "kexec handover debug interface"
> +	depends on KEXEC_HANDOVER
> +	depends on DEBUG_FS
> +	help
> +	  Allow to control kexec handover device tree via debugfs
> +	  interface, i.e. finalize the state or aborting the finalization.
> +	  Also, enables inspecting the KHO fdt trees with the debugfs binary
> +	  blobs.
> +
[...]

-- 
Regards,
Pratyush Yadav