On Tue, Oct 20, 2015 at 11:46:27AM +0200, Lars-Peter Clausen wrote:
The DMAengine API has a long standing issue that is inherent to the API itself. For a client that calls dmaengine_terminate_all() it is not possible to properly synchronize the completion of any currently running complete callbacks to the current context. This means it is possible to end up with a use-after-free race condition if client frees resources that are accessed in a complete callback before the complete callback has finished running.
This patch series introduces a new explicit synchronization primitive to the DMAengine API which allows clients to ensure that all complete callbacks have finished running. This allows them to safely free any resources that might be accessed in a complete callback.
The series for now only implements synchronization support for a single driver and only updates single client to make use of the new API. If there is agreement on the general approach more will follow.
Thanks Lars for getting this done.
I have merged this to topic/test/async branch and this will be in next kernel revision. We are too close to merge window right now