Hi Jonathan, I have one question about a cases when trigger owner is builtin module. In the such cases trig->owner == null, because THIS_MODULE equals to null. How do you think, should we take into account such situations? IMHO we have to take in and save this information to trig_info during trigger allocation call. For example we can check THIS_MODULE from the iio_trigger_alloc(), save builtin status to trig_info and look into it from iio_trigger_get(). On Tue, May 31, 2022 at 06:15:05PM +0000, Dmitry Rokosov wrote: > As a part of patch series about wrong trigger register() and get() > calls order in the some IIO drivers trigger initialization path: > > https://lore.kernel.org/all/20220524181150.9240-1-ddrokosov@xxxxxxxxxxxxxx/ > > runtime WARN() is added to alarm IIO driver authors who make such > a mistake. > > When IIO driver allocates a new IIO trigger, it should register it before > calling get() operation. Otherwise, the next iio_trigger_put() will upset > refcnt balance. > > Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> > --- > include/linux/iio/trigger.h | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h > index 4c69b144677b..4a008b952710 100644 > --- a/include/linux/iio/trigger.h > +++ b/include/linux/iio/trigger.h > @@ -93,6 +93,15 @@ static inline void iio_trigger_put(struct iio_trigger *trig) > static inline struct iio_trigger *iio_trigger_get(struct iio_trigger *trig) > { > get_device(&trig->dev); > + > + /* > + * If driver hasn't called iio_trigger_register() before and trig->owner > + * wasn't initialized properly, trigger will have wrong number of users > + */ > + WARN(!trig->owner, > + "Ignore module getting for non-registered iio trigger %s\n", > + trig->name); > + > __module_get(trig->owner); > > return trig; > -- > 2.36.0 -- Thank you, Dmitry
