Is there some implicit locking of device methods?

[Warner Losh]

On Apr 26, 2011, at 6:17 PM, Bartosz Fabianowski wrote:

>> If you needs per-file private data for cdev, you would be better served
>> by cdevpriv(9) KPI. Cloning is too hard to use correctly for such task.
> 
> Thanks, I just got that working. To help those going down a similar path in the future, I would like to note quickly that the following must be added to the cdevsw structure to ensure proper clean-up:
> 
> .d_flags = D_TRACKCLOSE
> 
> I just spent hours debugging panics until I realized only the last close() was triggering a call to my .d_close method.

Traditional BSD behavior...

Warner