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

Herve Codina
2025-12-04T07:39:05Z

Hi Kalle,

On Wed, 3 Dec 2025 12:11:45 +0200
Kalle Niemi <kaleposti@gmail.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@ec500000/rcar_sound,src/src-0
rcar_sound ec500000.sound: Failed to create device link (0x180) with
supplier soc for /soc/sound@ec500000/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@google.com>) seems incorrect.
Got emails delivery failure with this email address.

Best regards,
Hervé