[FELIX-5942] Felix Framework freezes when resolving classes in parallel with Java 10

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: framework-6.0.1
• Fix Version/s: framework-6.0.2
• Component/s: Framework
• Assignee: Karl Pauls
• Reporter: Antoine DESSAIGNE
• Created: 24/Sep/18 13:39
• Updated: 31/Jan/19 13:08
• Resolved: 24/Sep/18 18:38

Description

Hello.

When resolving a class in parallel in Java 10, you end up with a freeze.

You end up with threads beeing blocked

"Thread-99" #121 prio=5 os_prio=0 tid=0x000001bdaf679000 nid=0x69d4 in Object.wait()  [0x000000296d0fe000]
   java.lang.Thread.State: BLOCKED (on object monitor)
	at java.lang.Object.wait(java.base@10.0.2/Native Method)
	- waiting on <0x00000006c931dd20> (a [Ljava.lang.Object;)
	at java.lang.Object.wait(java.base@10.0.2/Object.java:328)
	at org.apache.felix.framework.Felix.acquireGlobalLock(Felix.java:4301)
	- waiting to re-lock in wait() <0x00000006c931dd20> (a [Ljava.lang.Object;)
	at org.apache.felix.framework.StatefulResolver.resolve(StatefulResolver.java:413)
	at org.apache.felix.framework.Felix.resolveBundleRevision(Felix.java:3318)
	at org.apache.felix.framework.Felix.loadBundleClass(Felix.java:1618)
	at org.apache.felix.framework.BundleImpl.loadClass(BundleImpl.java:978)
	at org.apache.felix.framework.ConcurrentClassLoaderTest$1.run(ConcurrentClassLoaderTest.java:69)

You'll find attached a test reproducing the issue : ConcurrentClassLoaderTest.java

Here's what you need to freeze felix :

• Lots of threads trying to acquire the global lock
  • here we're resolving a class from a bundle with dynamic import packages
• An Oracle JDK 10 or OpenJDK 11
  • it's working fine with Oracle JDK 8

 

Replacing the m_bundleLock by a fair ReentrantLock with a Condition makes it work with 10 parallel threads but still fails with 100 threads.

Issue Links

• links to: GitHub Pull Request #156