X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=9a373dec456223cfbac60cd4ce8729adbf3d7a13;hb=ccad6013892a95574e7c3ec652f3e03c357d10b7;hp=19ebc5e6eeeb79ef8ce12a3835372b1581edae95;hpb=3ce43c20dee3d0c7afc4ff3b4c67e0530ab2138f;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index 19ebc5e6..9a373dec 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1622,13 +1622,11 @@ void Thread::idle_loop() {
 
   // Pointer 'this_sp' is not null only if we are called from split(), and not
   // at the thread creation. So it means we are the split point's master.
-  const SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : NULL;
+  SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : NULL;
 
   assert(!this_sp || (this_sp->masterThread == this && searching));
 
-  // If this thread is the master of a split point and all slaves have finished
-  // their work at this split point, return from the idle loop.
-  while (!this_sp || this_sp->slavesMask)
+  while (true)
   {
       // If we are not searching, wait for a condition to be signaled instead of
       // wasting CPU time polling for work.
@@ -1721,6 +1719,17 @@ void Thread::idle_loop() {
           // unsafe because if we are exiting there is a chance are already freed.
           sp->mutex.unlock();
       }
+
+      // If this thread is the master of a split point and all slaves have finished
+      // their work at this split point, return from the idle loop.
+      if (this_sp && !this_sp->slavesMask)
+      {
+          this_sp->mutex.lock();
+          bool finished = !this_sp->slavesMask; // Retest under lock protection
+          this_sp->mutex.unlock();
+          if (finished)
+              return;
+      }
   }
 }