linux-kernel - Re: [PATCH 29/34] drm: zynqmp_dp: convert to devm_drm_bridge

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Message-ID: <20250424132804.30bcc49a@booty>
Date: Thu, 24 Apr 2025 13:28:04 +0200
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc: Anusha Srivatsa <asrivats@...hat.com>, Paul Kocialkowski
 <paulk@...-base.io>, Dmitry Baryshkov <lumag@...nel.org>, Hervé Codina <herve.codina@...tlin.com>, Hui Pu
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Subject: Re: [PATCH 29/34] drm: zynqmp_dp: convert to
 devm_drm_bridge_alloc() API

Hello Tomi,

On Wed, 16 Apr 2025 15:31:41 +0300
Tomi Valkeinen <tomi.valkeinen@...asonboard.com> wrote:

> Hi,
> 
> On 07/04/2025 17:23, Luca Ceresoli wrote:
> > This is the new API for allocating DRM bridges.
> > 
> > This driver has a peculiar structure. zynqmp_dpsub.c is the actual driver,
> > which delegates to a submodule (zynqmp_dp.c) the allocation of a
> > sub-structure embedding the drm_bridge and its initialization, however it
> > does not delegate the drm_bridge_add(). Hence, following carefully the code
> > flow, it is correct to change the allocation function and .funcs assignment
> > in the submodule, while the drm_bridge_add() is not in that submodule.
> > 
> > Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>

[...]

> To add to my last mail, this clearly cannot be right, as it changes 
> kzalloc call to devm_* call, without removing the kfree()s...

Thank you very much for having tested this patch and found the mistake!
I have checked all other patches in the series and found no other
instance of this specific flaw, but a couple flaws of a different
nature. I'm now fixing all of them and will send v2 later today.

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com