linux-kernel - Re: [PATCH v6 07/20] liveupdate: luo_session: Add ioctls for file preservation

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 for Android: free password hash cracker in your pocket

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

Message-ID: <aRoXGYC4GeAoNKPl@kernel.org>
Date: Sun, 16 Nov 2025 20:25:29 +0200
From: Mike Rapoport <rppt@...nel.org>
To: Pasha Tatashin <pasha.tatashin@...een.com>
Cc: pratyush@...nel.org, jasonmiu@...gle.com, graf@...zon.com,
	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, 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, ptyadav@...zon.de, 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
Subject: Re: [PATCH v6 07/20] liveupdate: luo_session: Add ioctls for file
 preservation

On Sat, Nov 15, 2025 at 06:33:53PM -0500, Pasha Tatashin wrote:
> Introducing the userspace interface and internal logic required to
> manage the lifecycle of file descriptors within a session. Previously, a
> session was merely a container; this change makes it a functional
> management unit.
> 
> The following capabilities are added:
> 
> A new set of ioctl commands are added, which operate on the file
> descriptor returned by CREATE_SESSION. This allows userspace to:
> - LIVEUPDATE_SESSION_PRESERVE_FD: Add a file descriptor to a session
>   to be preserved across the live update.
> - LIVEUPDATE_SESSION_RETRIEVE_FD: Retrieve a preserved file in the
>   new kernel using its unique token.
> - LIVEUPDATE_SESSION_FINISH: finish session
> 
> The session's .release handler is enhanced to be state-aware. When a
> session's file descriptor is closed, it correctly unpreserves
> the session based on its current state before freeing all
> associated file resources.
> 
> Signed-off-by: Pasha Tatashin <pasha.tatashin@...een.com>
> ---
>  include/uapi/linux/liveupdate.h | 103 ++++++++++++++++++
>  kernel/liveupdate/luo_session.c | 187 +++++++++++++++++++++++++++++++-
>  2 files changed, 286 insertions(+), 4 deletions(-)

...

>  static int luo_session_release(struct inode *inodep, struct file *filep)
>  {
>  	struct luo_session *session = filep->private_data;
>  	struct luo_session_header *sh;
> +	int err = 0;
>  
>  	/* If retrieved is set, it means this session is from incoming list */
> -	if (session->retrieved)
> +	if (session->retrieved) {
>  		sh = &luo_session_global.incoming;
> -	else
> +
> +		err = luo_session_finish_one(session);
> +		if (err) {
> +			pr_warn("Unable to finish session [%s] on release\n",
> +				session->name);

			return err;

and then else can go away here and luo_session_remove() and
luo_session_free() can be moved outside if (session->retrieved).

> +		} else {
> +			luo_session_remove(sh, session);
> +			luo_session_free(session);
> +		}
> +
> +	} else {
>  		sh = &luo_session_global.outgoing;
>  
> -	luo_session_remove(sh, session);
> -	luo_session_free(session);
> +		scoped_guard(mutex, &session->mutex)
> +			luo_file_unpreserve_files(session);
> +		luo_session_remove(sh, session);
> +		luo_session_free(session);
> +	}
> +
> +	return err;
> +}

-- 
Sincerely yours,
Mike.