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>
Subject: [PATCH v2 3/3] i2c: muxes: i2c-mux-gpmux: Use of_get_i2c_adapter_by_node()
Date: Thu, 19 Oct 2023 12:10:16 +0200 [thread overview]
Message-ID: <20231019101017.425284-4-herve.codina@bootlin.com> (raw)
In-Reply-To: <20231019101017.425284-1-herve.codina@bootlin.com>
i2c-mux-gpmux 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: ac8498f0ce53 ("i2c: i2c-mux-gpmux: new driver")
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Acked-by: Peter Rosin <peda@axentia.se>
---
drivers/i2c/muxes/i2c-mux-gpmux.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/muxes/i2c-mux-gpmux.c b/drivers/i2c/muxes/i2c-mux-gpmux.c
index baccf4bfaf02..8305661e1253 100644
--- a/drivers/i2c/muxes/i2c-mux-gpmux.c
+++ b/drivers/i2c/muxes/i2c-mux-gpmux.c
@@ -52,7 +52,7 @@ static struct i2c_adapter *mux_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
next prev parent reply other threads:[~2023-10-19 10:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-19 10:10 [PATCH v2 0/3] Fix i2c mux module refcount issues Herve Codina
2023-10-19 10:10 ` [PATCH v2 1/3] i2c: muxes: i2c-mux-pinctrl: Use of_get_i2c_adapter_by_node() Herve Codina
2023-10-19 18:01 ` Greg Kroah-Hartman
2023-10-20 7:34 ` Jonathan Cameron
2023-10-19 10:10 ` [PATCH v2 2/3] i2c: muxes: i2c-demux-pinctrl: " Herve Codina
2023-10-19 18:01 ` Greg Kroah-Hartman
2023-10-20 7:36 ` Jonathan Cameron
2023-10-19 10:10 ` Herve Codina [this message]
2023-10-19 18:00 ` [PATCH v2 3/3] i2c: muxes: i2c-mux-gpmux: " Greg Kroah-Hartman
2023-10-20 7:37 ` Jonathan Cameron
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