| Message ID | 20231019101017.425284-3-herve.codina@bootlin.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Fix i2c mux module refcount issues | expand |
On Thu, 19 Oct 2023 12:10:15 +0200 Herve Codina <herve.codina@bootlin.com> 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 Odd spacing in here - looks like some tabs sneaked in. > 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 <herve.codina@bootlin.com> > Acked-by: Peter Rosin <peda@axentia.se> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > 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;
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;
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 <herve.codina@bootlin.com> Acked-by: Peter Rosin <peda@axentia.se> --- drivers/i2c/muxes/i2c-demux-pinctrl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)