#1349 tbb::mutex is moved to outer scope to be sure that its initialization is completed before the parallel loop

modules/nonfree/src/surf.cpp

@@ -257,6 +257,10 @@ interpolateKeypoint( float N9[3][9], int dx, int dy, int ds, KeyPoint& kpt )
     return ok;
 }
 
+#ifdef HAVE_TBB
+static tbb::mutex findMaximaInLayer_m;
+#endif
+
 /*
  * Find the maxima in the determinant of the Hessian in a layer of the
  * scale-space pyramid
@@ -352,10 +356,9 @@ findMaximaInLayer( const Mat& sum, const Mat& mask_sum,
                     if( interp_ok  )
                     {
                         /*printf( "KeyPoint %f %f %d\n", point.pt.x, point.pt.y, point.size );*/
-                    #ifdef HAVE_TBB
-                        static tbb::mutex m;
-                        tbb::mutex::scoped_lock lock(m);
-                    #endif
+#ifdef HAVE_TBB
+                        tbb::mutex::scoped_lock lock(findMaximaInLayer_m);
+#endif
                         keypoints.push_back(kpt);
                     }
                 }
@@ -411,6 +414,11 @@ struct SURFFindInvoker
         keypoints = &_keypoints;
         nOctaveLayers = _nOctaveLayers;
         hessianThreshold = _hessianThreshold;
+
+#ifdef HAVE_TBB
+        //touch the mutex to ensure that it's initialization is finished
+        CV_Assert(&findMaximaInLayer_m > 0);
+#endif
     }
 
     void operator()(const BlockedRange& range) const