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From: Herve Codina <herve.codina@bootlin.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Peter Rosin <peda@axentia.se>,
	Stephen Warren <swarren@nvidia.com>,
	Rob Herring <robh@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jonathan Cameron <jic23@kernel.org>
Cc: 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>,
	Herve Codina <herve.codina@bootlin.com>,
	stable@vger.kernel.org,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: [PATCH v3 1/3] i2c: muxes: i2c-mux-pinctrl: Use of_get_i2c_adapter_by_node()
Date: Fri, 20 Oct 2023 17:30:11 +0200	[thread overview]
Message-ID: <20231020153017.759926-2-herve.codina@bootlin.com> (raw)
In-Reply-To: <20231020153017.759926-1-herve.codina@bootlin.com>

i2c-mux-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: c4aee3e1b0de ("i2c: mux: pinctrl: remove platform_data")
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Cc: stable@vger.kernel.org
Acked-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/i2c/muxes/i2c-mux-pinctrl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index 18236b9fa14a..6ebca7bfd8a2 100644
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -62,7 +62,7 @@ static struct i2c_adapter *i2c_mux_pinctrl_parent_adapter(struct device *dev)
 		dev_err(dev, "Cannot parse i2c-parent\n");
 		return ERR_PTR(-ENODEV);
 	}
-	parent = of_find_i2c_adapter_by_node(parent_np);
+	parent = of_get_i2c_adapter_by_node(parent_np);
 	of_node_put(parent_np);
 	if (!parent)
 		return ERR_PTR(-EPROBE_DEFER);
-- 
2.41.0


       reply	other threads:[~2023-10-20 15:30 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20231020153017.759926-1-herve.codina@bootlin.com>
2023-10-20 15:30 ` Herve Codina [this message]
2023-10-21 17:57   ` [PATCH v3 1/3] i2c: muxes: i2c-mux-pinctrl: Use of_get_i2c_adapter_by_node() Wolfram Sang
2023-10-20 15:30 ` [PATCH v3 2/3] i2c: muxes: i2c-demux-pinctrl: " Herve Codina
2023-10-21 17:57   ` Wolfram Sang
2023-10-20 15:30 ` [PATCH v3 3/3] i2c: muxes: i2c-mux-gpmux: " Herve Codina
2023-10-21 17:58   ` Wolfram Sang

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