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 <[email protected]>
Cc: [email protected]
Acked-by: Peter Rosin <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
---
drivers/i2c/muxes/i2c-demux-pinctrl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
index 22f2280eab7f..9f2e4aa28159 100644
--- a/drivers/i2c/muxes/i2c-demux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c
@@ -61,7 +61,7 @@ static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 ne
if (ret)
goto err;
- adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
+ adap = of_get_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
if (!adap) {
ret = -ENODEV;
goto err_with_revert;
--
2.41.0
On Fri, Oct 20, 2023 at 05:30:12PM +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 <[email protected]>
> Cc: [email protected]
> Acked-by: Peter Rosin <[email protected]>
> Reviewed-by: Jonathan Cameron <[email protected]>
Applied to for-current, thanks!