linux-kernel - Re: [PATCH v2 1/3] drm_gem: add mutex to drm_gem

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: <aKhNFn7hdsLapLWO@google.com>
Date: Fri, 22 Aug 2025 10:57:26 +0000
From: Alice Ryhl <aliceryhl@...gle.com>
To: Boris Brezillon <boris.brezillon@...labora.com>
Cc: 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>, 
	Danilo Krummrich <dakr@...nel.org>, Daniel Almeida <daniel.almeida@...labora.com>, 
	Steven Price <steven.price@....com>, Liviu Dudau <liviu.dudau@....com>, 
	Rob Clark <robin.clark@....qualcomm.com>, Rob Herring <robh@...nel.org>, 
	Miguel Ojeda <ojeda@...nel.org>, 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>, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	rust-for-linux@...r.kernel.org
Subject: Re: [PATCH v2 1/3] drm_gem: add mutex to drm_gem_object.gpuva

On Fri, Aug 22, 2025 at 11:52:21AM +0200, Boris Brezillon wrote:
> On Fri, 22 Aug 2025 09:28:24 +0000
> 
> Maybe it's time we start moving some bits of the gpuva field docs next
> to the fields they describe:
> 
> 	/**
> 	 * @gpuva: Fields used by GPUVM to manage mappings pointing to this GEM object.
> 	 */
> 	struct {
> 		/**
> 		 * @gpuva.list: list of GPU VAs attached to this GEM object.
> 		 *
> 		 * Drivers should lock list accesses with the GEMs &dma_resv lock
> 		 * (&drm_gem_object.resv) or &drm_gem_object.gpuva.lock if the
> 		 * list is being updated in places where the resv lock can't be
> 		 * acquired (fence signalling path).
> 		 */
> 		struct list_head list;

This isn't a new issue, but it's somewhat confusing to call it a list of
VAs when it's a list of vm_bos.

> 		/**
> 		 * @gpuva.lock: lock protecting access to &drm_gem_object.gpuva.list
> 		 * when the resv lock can't be used.
> 		 *
> 		 * Should only be used when the VM is being modified in a fence
> 		 * signalling path, otherwise you should use &drm_gem_object.resv to
> 		 * protect accesses to &drm_gem_object.gpuva.list.
> 		 */
> 		struct mutex lock;
> 
> 		...
> 	};
> 

Alice