Hi,
Some i2c mux drivers wrongly use the pair of_find_i2c_adapter_by_node()
/ i2c_put_adapter() to lock the 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.
Identified mux drivers impacted are:
- i2c-mux-gpmux
- i2c-demux-pinctrl
- i2c-mux-pinctrl
Commit 48e9743dd648 ("i2c: core: add and export of_get_i2c_adapter_by_node()
interface") introduces of_get_i2c_adapter_by_node() to correctly handle
this refcount issue.
This series fixes the 3 identified mux drivers replacing the
of_find_i2c_adapter_by_node() call by an of_get_i2c_adapter_by_node()
call.
Best regards,
Hervé
Herve Codina (3):
i2c: muxes: i2c-mux-pinctrl: Use of_get_i2c_adapter_by_node()
i2c: muxes: i2c-demux-pinctrl: Use of_get_i2c_adapter_by_node()
i2c: muxes: i2c-mux-gpmux: Use of_get_i2c_adapter_by_node()
drivers/i2c/muxes/i2c-demux-pinctrl.c | 2 +-
drivers/i2c/muxes/i2c-mux-gpmux.c | 2 +-
drivers/i2c/muxes/i2c-mux-pinctrl.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
--
2.41.0
i2c-mux-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
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 <[email protected]>
---
drivers/i2c/muxes/i2c-mux-pinctrl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index 18236b9fa14a..6ebca7bfd8a2 100644
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -62,7 +62,7 @@ static struct i2c_adapter *i2c_mux_pinctrl_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
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
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 <[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
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 <[email protected]>
---
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
Hi!
2023-10-19 at 09:35, Herve Codina wrote:
> i2c-mux-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
> overflow over zero of the parent adapter user counter.
Perhaps "... underflow of the parent module refcount."?
>
> Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
> correctly the module refcount.
>
> Signed-off-by: Herve Codina <[email protected]>
Good find, and sorry about that!
Fixes: c4aee3e1b0de ("i2c: mux: pinctrl: remove platform_data")
Acked-by: Peter Rosin <[email protected]>
Cheers,
Peter
> ---
> drivers/i2c/muxes/i2c-mux-pinctrl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
> index 18236b9fa14a..6ebca7bfd8a2 100644
> --- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
> +++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
> @@ -62,7 +62,7 @@ static struct i2c_adapter *i2c_mux_pinctrl_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);
Hi!
2023-10-19 at 09:35, 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
> overflow over zero of the parent adapter user counter.
Perhaps "... underflow of the parent module refcount."?
>
> Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
> correctly the module refcount.
>
> Signed-off-by: Herve Codina <[email protected]>
Good find!
Fixes: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
Acked-by: Peter Rosin <[email protected]>
Cheers,
Peter
> ---
> 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;
Hi!
2023-10-19 at 09:35, Herve Codina wrote:
> 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.
Perhaps "... underflow of the parent module refcount."?
>
> Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
> correctly the module refcount.
>
> Signed-off-by: Herve Codina <[email protected]>
Good find, and sorry about that!
Fixes: ac8498f0ce53 ("i2c: i2c-mux-gpmux: new driver")
Acked-by: Peter Rosin <[email protected]>
Cheers,
Peter
> ---
> 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);
Hi Peter,
On Thu, 19 Oct 2023 11:25:35 +0200
Peter Rosin <[email protected]> wrote:
> Hi!
>
> 2023-10-19 at 09:35, Herve Codina wrote:
> > i2c-mux-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
> > overflow over zero of the parent adapter user counter.
>
> Perhaps "... underflow of the parent module refcount."?
Yes, will be changed in the next iteration.
>
> >
> > Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
> > correctly the module refcount.
> >
> > Signed-off-by: Herve Codina <[email protected]>
>
> Good find, and sorry about that!
>
> Fixes: c4aee3e1b0de ("i2c: mux: pinctrl: remove platform_data")
> Acked-by: Peter Rosin <[email protected]>
>
Will be added in the next iteration.
Thanks for the review,
Hervé
Hi Peter,
On Thu, 19 Oct 2023 11:26:14 +0200
Peter Rosin <[email protected]> wrote:
> Hi!
>
> 2023-10-19 at 09:35, 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
> > overflow over zero of the parent adapter user counter.
>
> Perhaps "... underflow of the parent module refcount."?
Will be changed in the next iteration
>
> >
> > Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
> > correctly the module refcount.
> >
> > Signed-off-by: Herve Codina <[email protected]>
>
> Good find!
>
> Fixes: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
> Acked-by: Peter Rosin <[email protected]>
>
Will be added in the next iteration.
Thanks for the review,
Hervé
Hi Peter,
On Thu, 19 Oct 2023 11:26:41 +0200
Peter Rosin <[email protected]> wrote:
> Hi!
>
> 2023-10-19 at 09:35, Herve Codina wrote:
> > 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.
>
> Perhaps "... underflow of the parent module refcount."?
Yes, will be changed in the next iteration.
>
> >
> > Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
> > correctly the module refcount.
> >
> > Signed-off-by: Herve Codina <[email protected]>
>
> Good find, and sorry about that!
>
> Fixes: ac8498f0ce53 ("i2c: i2c-mux-gpmux: new driver")
> Acked-by: Peter Rosin <[email protected]>
Will be added in the next iteration.
Thanks for the review,
Hervé