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Message-ID: <20231019073533.386563-4-herve.codina@bootlin.com>
Date: Thu, 19 Oct 2023 09:35:30 +0200
From: Herve Codina <herve.codina@...tlin.com>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>,
Peter Rosin <peda@...ntia.se>
Cc: linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
Allan Nielsen <allan.nielsen@...rochip.com>,
Horatiu Vultur <horatiu.vultur@...rochip.com>,
Steen Hegelund <steen.hegelund@...rochip.com>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Herve Codina <herve.codina@...tlin.com>
Subject: [PATCH 3/3] i2c: muxes: i2c-mux-gpmux: Use of_get_i2c_adapter_by_node()
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
overflow over zero of the parent adapter user counter.
Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
correctly the module refcount.
Signed-off-by: Herve Codina <herve.codina@...tlin.com>
---
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
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