linux-kernel - Re: [PATCH v3 29/30] luo: allow preserving memfd

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: <aLXIcUwt0HVzRpYW@kernel.org>
Date: Mon, 1 Sep 2025 19:23:13 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Jason Gunthorpe <jgg@...dia.com>
Cc: Pasha Tatashin <pasha.tatashin@...een.com>, pratyush@...nel.org,
	jasonmiu@...gle.com, graf@...zon.com, changyuanl@...gle.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, 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, 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, parav@...dia.com, leonro@...dia.com,
	witu@...dia.com
Subject: Re: [PATCH v3 29/30] luo: allow preserving memfd

On Tue, Aug 26, 2025 at 01:20:19PM -0300, Jason Gunthorpe wrote:
> On Thu, Aug 07, 2025 at 01:44:35AM +0000, Pasha Tatashin wrote:
> 
> > +	/*
> > +	 * Most of the space should be taken by preserved folios. So take its
> > +	 * size, plus a page for other properties.
> > +	 */
> > +	fdt = memfd_luo_create_fdt(PAGE_ALIGN(preserved_size) + PAGE_SIZE);
> > +	if (!fdt) {
> > +		err = -ENOMEM;
> > +		goto err_unpin;
> > +	}
> 
> This doesn't seem to have any versioning scheme, it really should..
> 
> > +	err = fdt_property_placeholder(fdt, "folios", preserved_size,
> > +				       (void **)&preserved_folios);
> > +	if (err) {
> > +		pr_err("Failed to reserve folios property in FDT: %s\n",
> > +		       fdt_strerror(err));
> > +		err = -ENOMEM;
> > +		goto err_free_fdt;
> > +	}
> 
> Yuk.
> 
> This really wants some luo helper
> 
> 'luo alloc array'
> 'luo restore array'
> 'luo free array'

We can just add kho_{preserve,restore}_vmalloc(). I've drafted it here:
https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=kho/vmalloc/v1

Will wait for kbuild and then send proper patches.
 

-- 
Sincerely yours,
Mike.