--- xnu/xnu-3248.50.21/iokit/Kernel/IOInterruptController.cpp
+++ xnu/xnu-3789.51.2/iokit/Kernel/IOInterruptController.cpp
@@ -519,6 +519,7 @@
   // Create the vectorData for the IOInterruptSource.
   vectorData = OSData::withBytes(&vectorNumber, sizeof(vectorNumber));
   if (vectorData == 0) {
+    IOLockUnlock(vector->interruptLock);
     return kIOReturnNoMemory;
   }