[PATCH v2] i2c: i801: Avoid potential double call to gpiod_remove_lookup_table

[PATCH v2] i2c: i801: Avoid potential double call to gpiod_remove_lookup_table

[Heiner Kallweit]

If registering the platform device fails, the lookup table is
removed in the error path. On module removal we would try to
remove the lookup table again. Fix this by leaving it to
i801_del_mux() to clean up.

Fixes: d308dfbf62ef ("i2c: mux/i801: Switch to use descriptor passing")
Cc: stable@vger.kernel.org
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- cc stable
- free memory allocated for the lookup table
---
 drivers/i2c/busses/i2c-i801.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 291c609d1..9c624f31c 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1428,7 +1428,6 @@ static void i801_add_mux(struct i801_priv *priv)
 		lookup->table[i] = GPIO_LOOKUP(mux_config->gpio_chip,
 					       mux_config->gpios[i], "mux", 0);
 	gpiod_add_lookup_table(lookup);
-	priv->lookup = lookup;
 
 	/*
 	 * Register the mux device, we use PLATFORM_DEVID_NONE here
@@ -1442,7 +1441,10 @@ static void i801_add_mux(struct i801_priv *priv)
 				sizeof(struct i2c_mux_gpio_platform_data));
 	if (IS_ERR(priv->mux_pdev)) {
 		gpiod_remove_lookup_table(lookup);
+		devm_kfree(dev, lookup);
 		dev_err(dev, "Failed to register i2c-mux-gpio device\n");
+	} else {
+		priv->lookup = lookup;
 	}
 }
 
-- 
2.44.0

Re: [PATCH v2] i2c: i801: Avoid potential double call to gpiod_remove_lookup_table

[Andi Shyti]

On Sun, Mar 03, 2024 at 11:41:44AM +0100, Heiner Kallweit wrote:
> If registering the platform device fails, the lookup table is
> removed in the error path. On module removal we would try to
> remove the lookup table again. Fix this by leaving it to
> i801_del_mux() to clean up.
> 
> Fixes: d308dfbf62ef ("i2c: mux/i801: Switch to use descriptor passing")
> Cc: stable@vger.kernel.org
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

You might want to Cc also Linus Walleij here as the patch is from
him.

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Just a little thought...

> ---
> v2:
> - cc stable
> - free memory allocated for the lookup table
> ---
>  drivers/i2c/busses/i2c-i801.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 291c609d1..9c624f31c 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -1428,7 +1428,6 @@ static void i801_add_mux(struct i801_priv *priv)
>  		lookup->table[i] = GPIO_LOOKUP(mux_config->gpio_chip,
>  					       mux_config->gpios[i], "mux", 0);
>  	gpiod_add_lookup_table(lookup);
> -	priv->lookup = lookup;
>  
>  	/*
>  	 * Register the mux device, we use PLATFORM_DEVID_NONE here
> @@ -1442,7 +1441,10 @@ static void i801_add_mux(struct i801_priv *priv)
>  				sizeof(struct i2c_mux_gpio_platform_data));
>  	if (IS_ERR(priv->mux_pdev)) {
>  		gpiod_remove_lookup_table(lookup);
> +		devm_kfree(dev, lookup);

perhaps you also want to set priv->lookup to NULL. It's not
really needed, but it's just some paranoiac thinking.

Andi

>  		dev_err(dev, "Failed to register i2c-mux-gpio device\n");
> +	} else {
> +		priv->lookup = lookup;
>  	}
>  }
>  
> -- 
> 2.44.0
>