diff --git a/bundles/org.eclipse.equinox.weaving.caching/src/org/eclipse/equinox/weaving/internal/caching/ClassnameLockManager.java b/bundles/org.eclipse.equinox.weaving.caching/src/org/eclipse/equinox/weaving/internal/caching/ClassnameLockManager.java
index 3b0ace86f28..432b8118323 100644
--- a/bundles/org.eclipse.equinox.weaving.caching/src/org/eclipse/equinox/weaving/internal/caching/ClassnameLockManager.java
+++ b/bundles/org.eclipse.equinox.weaving.caching/src/org/eclipse/equinox/weaving/internal/caching/ClassnameLockManager.java
@@ -119,6 +119,11 @@ private Lock acquireLock(final String classname, final boolean writeLock) {
 			return resultingEntry;
 		});
 
+		// now activate the lock - this must happen outside of the compute() because
+		// otherwise we would end up in a deadlock with the classnameLocks
+		// ConcurrentHashMap lock in releaseLock()
+		lockWrapper[0].lock();
+
 		// return the acquired lock
 		return lockWrapper[0];
 	}