linux-kernel - Re: [PATCH v4 01/29] Revert "treewide: Fix probing of devices in DT overlays"

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Message-ID: <20251204083839.4fb8a4b1@bootlin.com>
Date: Thu, 4 Dec 2025 08:38:39 +0100
From: Herve Codina <herve.codina@...tlin.com>
To: Kalle Niemi <kaleposti@...il.com>, Rob Herring <robh@...nel.org>, Matti
 Vaittinen <mazziesaccount@...il.com>, Geert Uytterhoeven
 <geert+renesas@...der.be>, linux-arm-kernel@...ts.infradead.org
Cc: Andrew Lunn <andrew@...n.ch>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Greg Kroah-Hartman
 <gregkh@...uxfoundation.org>, "Rafael J. Wysocki" <rafael@...nel.org>,
 Danilo Krummrich <dakr@...nel.org>, Shawn Guo <shawnguo@...nel.org>, Sascha
 Hauer <s.hauer@...gutronix.de>, Pengutronix Kernel Team
 <kernel@...gutronix.de>, Fabio Estevam <festevam@...il.com>, Michael
 Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>, Andi
 Shyti <andi.shyti@...nel.org>, Wolfram Sang
 <wsa+renesas@...g-engineering.com>, Peter Rosin <peda@...ntia.se>, Arnd
 Bergmann <arnd@...db.de>, Saravana Kannan <saravanak@...gle.com>, Bjorn
 Helgaas <bhelgaas@...gle.com>, Charles Keepax
 <ckeepax@...nsource.cirrus.com>, Richard Fitzgerald
 <rf@...nsource.cirrus.com>, David Rhodes <david.rhodes@...rus.com>, Linus
 Walleij <linus.walleij@...aro.org>, Ulf Hansson <ulf.hansson@...aro.org>,
 Mark Brown <broonie@...nel.org>, Andy Shevchenko
 <andriy.shevchenko@...ux.intel.com>, Daniel Scally <djrscally@...il.com>,
 Heikki Krogerus <heikki.krogerus@...ux.intel.com>, Sakari Ailus
 <sakari.ailus@...ux.intel.com>, Len Brown <lenb@...nel.org>, Davidlohr
 Bueso <dave@...olabs.net>, Jonathan Cameron <jonathan.cameron@...wei.com>,
 Dave Jiang <dave.jiang@...el.com>, Alison Schofield
 <alison.schofield@...el.com>, Vishal Verma <vishal.l.verma@...el.com>, Ira
 Weiny <ira.weiny@...el.com>, Dan Williams <dan.j.williams@...el.com>,
 Wolfram Sang <wsa@...nel.org>, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, imx@...ts.linux.dev,
 linux-clk@...r.kernel.org, linux-i2c@...r.kernel.org,
 linux-pci@...r.kernel.org, linux-sound@...r.kernel.org,
 patches@...nsource.cirrus.com, linux-gpio@...r.kernel.org,
 linux-pm@...r.kernel.org, linux-spi@...r.kernel.org,
 linux-acpi@...r.kernel.org, linux-cxl@...r.kernel.org, Allan Nielsen
 <allan.nielsen@...rochip.com>, Horatiu Vultur
 <horatiu.vultur@...rochip.com>, Steen Hegelund
 <steen.hegelund@...rochip.com>, Luca Ceresoli <luca.ceresoli@...tlin.com>,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v4 01/29] Revert "treewide: Fix probing of devices in DT
 overlays"

Hi Kalle,

On Wed, 3 Dec 2025 12:11:45 +0200
Kalle Niemi <kaleposti@...il.com> wrote:

...
> 
> I tried this patch on next-20251127 by manually adding the added lines 
> to /drivers/of/overlay.c, and it did not solve the issue. I will 
> continue to test this.
> 

Did you observe same traces reported by Geert?

To move forward, I think I will need help.

Indeed, Kalle, Geert, I don't have your hardware, your related overlay or
a similar one that could be used for test and also I don't have your out of
tree code used to handle this overlay.

I know overlays and fw_devlink have issues. Links created by fw_devlink
when an overlay is applied were not correct on my side.

Can you check your <supplier>--<consumer> links with 'ls /sys/class/devlinks'

On my side, without my patches some links were not correct.
They linked to the parent of the supplier instead of the supplier itself.
The consequence is a kernel crash, use after free, refcounting failure, ...
when the supplier device is removed.

Indeed, with wrong links consumers were not removed before suppliers they
used.

Looking at Geert traces:
--- 8< ---
rcar_sound ec500000.sound: Failed to create device link (0x180) with
supplier soc for /soc/sound@...00000/rcar_sound,src/src-0
rcar_sound ec500000.sound: Failed to create device link (0x180) with
supplier soc for /soc/sound@...00000/rcar_sound,src/src-1
[...]
--- 8< ---

Even if it is not correct, why the soc device cannot be a provider?
I don't have the answer to this question yet.

Without having the exact tree structure of the base device-tree, the overlay
and the way it is applied, and so without been able to reproduce the issue
on my side, investigating the issue is going to be difficult.

I hope to find some help to move forward and fix the issue.

Saravana's email (Saravana Kannan <saravanak@...gle.com>) seems incorrect.
Got emails delivery failure with this email address.

Best regards,
Hervé