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)