linux-kernel - Re: [PATCH] drm: sti: fix device leaks at component probe

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: <aQj69wzTceDklx2Y@thinkstation>
Date: Mon, 3 Nov 2025 19:56:55 +0100
From: Raphaël Gallais-Pou <rgallaispou@...il.com>
To: Markus Elfring <Markus.Elfring@....de>
Cc: Johan Hovold <johan@...nel.org>, dri-devel@...ts.freedesktop.org,
	stable@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	Alain Volmat <alain.volmat@...s.st.com>,
	Benjamin Gaignard <benjamin.gaignard@...labora.com>,
	David Airlie <airlied@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>, Simona Vetter <simona@...ll.ch>,
	Thomas Zimmermann <tzimmermann@...e.de>
Subject: Re: [PATCH] drm: sti: fix device leaks at component probe

Le Mon, Sep 22, 2025 at 06:16:47PM +0200, Markus Elfring a écrit :
> > Make sure to drop the references taken to the vtg devices by
> 
>                                                 VTG device?

Video Timing Generator.  This IP creates a vsync pulse and synchonize
the components together.

> 
> 
> > of_find_device_by_node() when looking up their driver data during
> > component probe.
> …
> 
> How do you think about to increase the application of scope-based resource management?
> https://elixir.bootlin.com/linux/v6.17-rc7/source/include/linux/device.h#L1180

Oh... I wasn't aware of this.  FWIU it is a way to directly free an
allocated memory whenever a variable goes out of scope using the cleanup
attribute.

IMO this is also a clever solution to prevent the memory leak, and it
would be a shorter patch.  So basically, instead of calling put_device()
as Johan did, you would suggest something like this ?

diff --git i/drivers/gpu/drm/sti/sti_vtg.c w/drivers/gpu/drm/sti/sti_vtg.c
index ee81691b3203..5193196d9291 100644
--- i/drivers/gpu/drm/sti/sti_vtg.c
+++ w/drivers/gpu/drm/sti/sti_vtg.c
@@ -142,7 +142,7 @@ struct sti_vtg {

 struct sti_vtg *of_vtg_find(struct device_node *np)
 {
-       struct platform_device *pdev;
+       struct platform_device *pdev __free(put_device) = NULL;

Best regards,
Raphaël


> 
> Can a summary phrase like “Prevent device leak in of_vtg_find()” be nicer?
> 
> Regards,
> Markus