Make sure we re-acquire lock if a task throws

src/scheduler.cpp

@@ -6,6 +6,7 @@
 
 #include <assert.h>
 #include <boost/bind.hpp>
+#include <boost/thread/reverse_lock.hpp>
 #include <utility>
 
 CScheduler::CScheduler() : nThreadsServicingQueue(0), stopRequested(false), stopWhenEmpty(false)
@@ -65,11 +66,12 @@ void CScheduler::serviceQueue()
             Function f = taskQueue.begin()->second;
             taskQueue.erase(taskQueue.begin());
 
+            {
                 // Unlock before calling f, so it can reschedule itself or another task
                 // without deadlocking:
-            lock.unlock();
+                boost::reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock);
                 f();
-            lock.lock();
+            }
         } catch (...) {
             --nThreadsServicingQueue;
             throw;