linux-kernel - Re: [PATCH -next v7 1/2] rust: clist: Add support to interface with C linked lists

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] [day] [month] [year] [list]

Message-Id: <4A87E3FC-6A04-4A92-9230-4782D75FC05F@collabora.com>
Date: Fri, 6 Feb 2026 19:33:27 -0300
From: Daniel Almeida <daniel.almeida@...labora.com>
To: Joel Fernandes <joelagnelf@...dia.com>
Cc: linux-kernel@...r.kernel.org,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>,
 Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>,
 Jonathan Corbet <corbet@....net>,
 Alex Deucher <alexander.deucher@....com>,
 Christian König <christian.koenig@....com>,
 Jani Nikula <jani.nikula@...ux.intel.com>,
 Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
 Rodrigo Vivi <rodrigo.vivi@...el.com>,
 Tvrtko Ursulin <tursulin@...ulin.net>,
 Huang Rui <ray.huang@....com>,
 Matthew Auld <matthew.auld@...el.com>,
 Matthew Brost <matthew.brost@...el.com>,
 Lucas De Marchi <lucas.demarchi@...el.com>,
 Thomas Hellström <thomas.hellstrom@...ux.intel.com>,
 Helge Deller <deller@....de>,
 Danilo Krummrich <dakr@...nel.org>,
 Alice Ryhl <aliceryhl@...gle.com>,
 Miguel Ojeda <ojeda@...nel.org>,
 Alex Gaynor <alex.gaynor@...il.com>,
 Boqun Feng <boqun.feng@...il.com>,
 Gary Guo <gary@...yguo.net>,
 Björn Roy Baron <bjorn3_gh@...tonmail.com>,
 Benno Lossin <lossin@...nel.org>,
 Andreas Hindborg <a.hindborg@...nel.org>,
 Trevor Gross <tmgross@...ch.edu>,
 John Hubbard <jhubbard@...dia.com>,
 Alistair Popple <apopple@...dia.com>,
 Timur Tabi <ttabi@...dia.com>,
 Edwin Peer <epeer@...dia.com>,
 Alexandre Courbot <acourbot@...dia.com>,
 Andrea Righi <arighi@...dia.com>,
 Andy Ritger <aritger@...dia.com>,
 Zhi Wang <zhiw@...dia.com>,
 Balbir Singh <balbirs@...dia.com>,
 Philipp Stanner <phasta@...nel.org>,
 Elle Rhumsaa <elle@...thered-steel.dev>,
 joel@...lfernandes.org,
 nouveau@...ts.freedesktop.org,
 dri-devel@...ts.freedesktop.org,
 rust-for-linux@...r.kernel.org,
 linux-doc@...r.kernel.org,
 amd-gfx@...ts.freedesktop.org,
 intel-gfx@...ts.freedesktop.org,
 intel-xe@...ts.freedesktop.org,
 linux-fbdev@...r.kernel.org
Subject: Re: [PATCH -next v7 1/2] rust: clist: Add support to interface with C
 linked lists

>> 
>> 
>> Yeah, but my point being: is there a reason why the underlying list has to
>> remain read-only? Is this a safety requirement or an invariant that is established
>> by the code above?
> I'm not fully sure if it's an invariant or a safety requirement, but anyone
> creating a C list head on the rust side must guarantee that it is not modified.
> Since rust has no visibility on the C side, I believe it is a Rust invariant
> here that the existence of CListHead assumes that the list cannot be modified
> once Rust has access over it.  That is up to the creator (user) of the CListHead
> to guarantee. In the DRM buddy case, once the list is allocated and accessible
> from Rust, C code will not modify it while the Rust object exists.
> 
> Does that make sense, or is there a better way to document this?
> 
> --
> Joel Fernandes


In which case, I recommend moving this to a safety requirement when
creating the list.

I assume the purpose of not modifying the list on the C side is to avoid
corrupting the list in Rust somehow?

— Daniel