Changeset 16981 in vbox

Timestamp:

Feb 20, 2009 11:21:42 PM (16 years ago)

Author:

vboxsync

Message:

Main: Fixed the potential deadlock in Machine::openSession() when opening a session fails for some reason (#3653).

File:

• trunk/src/VBox/Main/MachineImpl.cpp (modified) (2 diffs)

trunk/src/VBox/Main/MachineImpl.cpp

@@ -3430 +3430 @@
     AssertComRC (rc);
 
+    /* NOTE: doing return from this function after this point but
+     * before the end is forbidden since it may call SessionMachine::uninit()
+     * (through the ComObjPtr's destructor) which requests the VirtualBox write
+     * lock while still holding the Machine lock in alock so that a deadlock
+     * is possible due to the wrong lock order. */
+
     if (SUCCEEDED (rc))
     {
@@ -3562 +3568 @@
         mData->mSession.mProgress.setNull();
     }
+
+    /* Leave the lock since SessionMachine::uninit() locks VirtualBox which
+     * would break the lock order */
+    alock.leave();
 
     /* uninitialize the created session machine on failure */