linux-kernel - Re: [PATCH V3 2/2] of/platform: increase refcount of fwnode

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Message-ID: <169265161637.2283882.6488993918028899667.robh@kernel.org>
Date:   Mon, 21 Aug 2023 16:00:20 -0500
From:   Rob Herring <robh@...nel.org>
To:     "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc:     linux-kernel@...r.kernel.org, frowand.list@...il.com,
        krzysztof.kozlowski+dt@...aro.org, isaacmanjarres@...gle.com,
        conor+dt@...nel.org, rafael@...nel.org, devicetree@...r.kernel.org,
        jeremy.kerr@...onical.com, robh+dt@...nel.org,
        gregkh@...uxfoundation.org, linux@...linux.org.uk, arnd@...db.de,
        hdegoede@...hat.com, andriy.shevchenko@...ux.intel.com,
        grant.likely@...retlab.ca, Peng Fan <peng.fan@....com>,
        ulf.hansson@...aro.org, linus.walleij@...aro.org
Subject: Re: [PATCH V3 2/2] of/platform: increase refcount of fwnode


On Mon, 21 Aug 2023 10:39:28 +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@....com>
> 
> commit 0f8e5651095b
> ("of/platform: Propagate firmware node by calling device_set_node()")
> use of_fwnode_handle to replace of_node_get, which introduces a side
> effect that the refcount is not increased. Then the out of tree
> jailhouse hypervisor enable/disable test will trigger kernel dump in
> of_overlay_remove, with the following sequence
> "
>    of_changeset_revert(&overlay_changeset);
>    of_changeset_destroy(&overlay_changeset);
>    of_overlay_remove(&overlay_id);
> "
> 
> So increase the refcount to avoid issues.
> 
> This patch also release the refcount when releasing amba device to avoid
> refcount leakage.
> 
> Fixes: 0f8e5651095b ("of/platform: Propagate firmware node by calling device_set_node()")
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
> 
> V3:
>  - Move amba device changes to patch 1/1
> 
> V2:
>  - Per Andy's comment, use of_fwnode_handle(of_node_get(np))
>  - release amba device of_node refcount when releasing amba device, this is
>    done from code inspection, no test.
> 
>  drivers/of/platform.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 

Applied, thanks!