| Message ID | 20220524181150.9240-4-ddrokosov@sberdevices.ru (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | iio: treewide: rearrange iio trig get/register | expand |
On Tue, May 24, 2022 at 8:14 PM Dmitry Rokosov <DDRokosov@sberdevices.ru> wrote: > > IIO trigger interface function iio_trigger_get() should be called after > iio_trigger_register() (or its devm analogue) strictly, because of > iio_trigger_get() acquires module refcnt based on the trigger->owner > pointer, which is initialized inside iio_trigger_register() to > THIS_MODULE. > If this call order is wrong, the next iio_trigger_put() (from sysfs > callback or "delete module" path) will dereference "default" module > refcnt, which is incorrect behaviour. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > Fixes: 47196620c82f ("iio: mxc4005: add data ready trigger for mxc4005") > Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru> > --- > drivers/iio/accel/mxc4005.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/accel/mxc4005.c b/drivers/iio/accel/mxc4005.c > index b3afbf064915..df600d2917c0 100644 > --- a/drivers/iio/accel/mxc4005.c > +++ b/drivers/iio/accel/mxc4005.c > @@ -456,8 +456,6 @@ static int mxc4005_probe(struct i2c_client *client, > > data->dready_trig->ops = &mxc4005_trigger_ops; > iio_trigger_set_drvdata(data->dready_trig, indio_dev); > - indio_dev->trig = data->dready_trig; > - iio_trigger_get(indio_dev->trig); > ret = devm_iio_trigger_register(&client->dev, > data->dready_trig); > if (ret) { > @@ -465,6 +463,8 @@ static int mxc4005_probe(struct i2c_client *client, > "failed to register trigger\n"); > return ret; > } > + > + indio_dev->trig = iio_trigger_get(data->dready_trig); > } > > return devm_iio_device_register(&client->dev, indio_dev); > -- > 2.36.0
diff --git a/drivers/iio/accel/mxc4005.c b/drivers/iio/accel/mxc4005.c index b3afbf064915..df600d2917c0 100644 --- a/drivers/iio/accel/mxc4005.c +++ b/drivers/iio/accel/mxc4005.c @@ -456,8 +456,6 @@ static int mxc4005_probe(struct i2c_client *client, data->dready_trig->ops = &mxc4005_trigger_ops; iio_trigger_set_drvdata(data->dready_trig, indio_dev); - indio_dev->trig = data->dready_trig; - iio_trigger_get(indio_dev->trig); ret = devm_iio_trigger_register(&client->dev, data->dready_trig); if (ret) { @@ -465,6 +463,8 @@ static int mxc4005_probe(struct i2c_client *client, "failed to register trigger\n"); return ret; } + + indio_dev->trig = iio_trigger_get(data->dready_trig); } return devm_iio_device_register(&client->dev, indio_dev);
IIO trigger interface function iio_trigger_get() should be called after iio_trigger_register() (or its devm analogue) strictly, because of iio_trigger_get() acquires module refcnt based on the trigger->owner pointer, which is initialized inside iio_trigger_register() to THIS_MODULE. If this call order is wrong, the next iio_trigger_put() (from sysfs callback or "delete module" path) will dereference "default" module refcnt, which is incorrect behaviour. Fixes: 47196620c82f ("iio: mxc4005: add data ready trigger for mxc4005") Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru> --- drivers/iio/accel/mxc4005.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)