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Date:   Thu, 19 Oct 2023 20:01:07 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Herve Codina <herve.codina@bootlin.com>
Cc:     Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Peter Rosin <peda@axentia.se>,
        Stephen Warren <swarren@nvidia.com>,
        Rob Herring <robh@kernel.org>,
        Jonathan Cameron <jic23@kernel.org>,
        Wolfram Sang <wsa@kernel.org>, linux-i2c@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Allan Nielsen <allan.nielsen@microchip.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>,
        Steen Hegelund <steen.hegelund@microchip.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v2 2/3] i2c: muxes: i2c-demux-pinctrl: Use
 of_get_i2c_adapter_by_node()
Message-ID: <2023101954-desecrate-stock-5103@gregkh>
References: <20231019101017.425284-1-herve.codina@bootlin.com>
 <20231019101017.425284-3-herve.codina@bootlin.com>
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On Thu, Oct 19, 2023 at 12:10:15PM +0200, Herve Codina wrote:
> i2c-demux-pinctrl uses the pair of_find_i2c_adapter_by_node() /
> i2c_put_adapter(). These pair alone is not correct to properly lock the
> I2C parent adapter.
> 
> Indeed,	i2c_put_adapter() decrements the module refcount while
> of_find_i2c_adapter_by_node() does not increment it. This leads to an
> underflow of the parent module refcount.
> 
> Use the	dedicated function, of_get_i2c_adapter_by_node(), to handle
> correctly the module refcount.
> 
> Fixes: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> Acked-by: Peter Rosin <peda@axentia.se>
> ---
>  drivers/i2c/muxes/i2c-demux-pinctrl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
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- You have marked a patch with a "Fixes:" tag for a commit that is in an
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  Documentation/process/stable-kernel-rules.rst file for how to resolve
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If you wish to discuss this problem further, or you have questions about
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Greg will reply once he has dug out from the pending patches received
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thanks,

greg k-h's patch email bot