linux-kernel - Re: [PATCH v4 3/6] drm/tests: managed: Remove the waitqueue usage

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: <bu62aukq2iw36k52tvrimatph3hn6ec3a4c5gaf4orkak6igoz@do6v344l7g43>
Date: Mon, 8 Jan 2024 11:45:52 +0100
From: Maxime Ripard <mripard@...nel.org>
To: Michał Winiarski <michal.winiarski@...el.com>
Cc: intel-xe@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org, Rodrigo Vivi <rodrigo.vivi@...el.com>, 
	Michal Wajdeczko <michal.wajdeczko@...el.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Daniel Vetter <daniel@...ll.ch>, Javier Martinez Canillas <javierm@...hat.com>, 
	Maíra Canal <mcanal@...lia.com>
Subject: Re: [PATCH v4 3/6] drm/tests: managed: Remove the waitqueue usage

On Fri, Jan 05, 2024 at 11:13:21AM +0100, Michał Winiarski wrote:
> DRM managed release (drm_managed_release) is called as part of devres
> release (devres_release_all), which is not async.
> The release action should have already been executed once
> drm_kunit_helper_free_device exits, meaning that there's no need to use
> a waitqueue - we can just inspect the "action_done" state directly.
> 
> Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>

I disagree, nothing guarantees in the API that it will be executed right
away. Since it might be asynchronous (if something else holds a
reference for example), we need the workqueue.

Fortunately, it turns out that it's actually done right away, which also
means we'll never hit the timeout and thus never stall the test run.

Maxime

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)