[jira] [Created] (FELIX-5215) Deadlocks involving global lock

["Julian Sedding (JIRA)" <ji...@apache.org>]

Julian Sedding created FELIX-5215:
-------------------------------------

             Summary: Deadlocks involving global lock
                 Key: FELIX-5215
                 URL: https://issues.apache.org/jira/browse/FELIX-5215
             Project: Felix
          Issue Type: Improvement
          Components: Framework
    Affects Versions: framework-5.4.0, framework-4.6.1
            Reporter: Julian Sedding


I have recently analyzed two thread dumps on a framework 4.6.1 with deadlocks involving the {{FelixFrameworkWiring}} thread calling {{Felix.refreshPackages}} and another thread.

In both cases the {{FelixFrameworkWiring}} thread holds Felix' global lock in {{Felix.refreshPackages}}, the other thread holds a lock in {{HttpServiceImpl}} and {{ServiceRegistry}}, respectively. (Note, both {{HttpServiceImpl}} and {{ServiceRegistry}} had their synchronization removed in trunk, possibly due to similar deadlocks).

While fixing the other players in the deadlock certainly helps, I was wondering if it would be possible to change the code inside the framework in a way that such deadlocks are no longer possible?

I believe section 4.7.3 "Synchronization Pitfalls" in the OSGi spec talks about this situation (quoted from v5.0.0):
{quote}
Generally, a bundle that calls a listener should not hold any Java monitors. This means that neither the Framework nor the originator of a synchronous event should be in a monitor when a callback is initiated.

[...]
{quote}



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)