linux-kernel - Re: [PATCH v13 2/7] rust: add dma coherent allocator abstraction.

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: <20250321172353.GO126678@ziepe.ca>
Date: Fri, 21 Mar 2025 14:23:53 -0300
From: Jason Gunthorpe <jgg@...pe.ca>
To: Abdiel Janulgue <abdiel.janulgue@...il.com>
Cc: rust-for-linux@...r.kernel.org, daniel.almeida@...labora.com,
	dakr@...nel.org, robin.murphy@....com, 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 <benno.lossin@...ton.me>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Trevor Gross <tmgross@...ch.edu>,
	Valentin Obst <kernel@...entinobst.de>,
	open list <linux-kernel@...r.kernel.org>,
	Christoph Hellwig <hch@....de>,
	Marek Szyprowski <m.szyprowski@...sung.com>, airlied@...hat.com,
	"open list:DMA MAPPING HELPERS" <iommu@...ts.linux.dev>
Subject: Re: [PATCH v13 2/7] rust: add dma coherent allocator abstraction.

On Fri, Mar 07, 2025 at 01:06:19PM +0200, Abdiel Janulgue wrote:

> +        // SAFETY: Device pointer is guaranteed as valid by the type invariant on `Device`.
> +        let ret = unsafe {
> +            bindings::dma_alloc_attrs(
> +                dev.as_raw(),
> +                size,
> +                &mut dma_handle,
> +                gfp_flags.as_raw(),
> +                dma_attrs.as_raw(),
> +            )

This is not the correct safety statement, the device must have a driver
bound to call this function, a struct device reference is not
sufficient.

I belive Danilo was suggesting to ignore this unsafety for now, but if
so it should be documented correctly.

Also think the use of devres here is going to be very problematic for
drivers to use as I said in other emails. :(

Jason