On Thu, Apr 19, 2018 at 03:10:27PM +0200, Alexandre Belloni wrote:

On 19/04/2018 14:41:27+0200, Christoph Hellwig wrote:

quoted

And stop trying to get a reference on the submodule, procfs code deals
with release after and unloaded module and thus removed proc entry.

Are you sure about that? The rtc module is not the one adding the procfs
file so I'm not sure how the procfs code can handle it.

The proc file is removed from this call chain:

  <driver>_exit (module_exit handler)
    -> rtc_device_unregister
      -> rtc_proc_del_device
        -> remove_proc_entry

remove_proc_entry takes care of waiting for currently active file
operation instances and makes sure every new operation never calls
into the actual proc file ops.  Same behavior as in RTC exists all
over the kernel.