- There is an assumption un uORB that PX4_F_RDONLY is not 0.
- But O_RDONLY is 0 on Linux. orb_exists passes 0 to px4_open, which in
uORB::DeviceNode::open leads to an unnecessary allocation of
SubscriberData()
- PX4_F_RDONLY is only used in combination with px4_open, never with open()
However even if it was wrong/unexpected, it did not cause any problems,
just the unnecessary allocation.