Fix another setting of a flag out of lock protection

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 8d0f758d08a35ebc433bb7e39444a626e476a9fa..dece7fd4958217523da01dbdae0dc0e5196fc971 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -70,7 +70,7 @@ namespace {
 
     int active_threads() const { return ActiveThreads; }
     void set_active_threads(int newActiveThreads) { ActiveThreads = newActiveThreads; }
-    void set_stop_request(int threadID) { threads[threadID].stop = true; }
+    void set_stop_request(int threadID) { threads[threadID].stopRequest = true; }
     void incrementNodeCounter(int threadID) { threads[threadID].nodes++; }
     void incrementBetaCounter(Color us, Depth d, int threadID) { threads[threadID].betaCutOffs[us] += unsigned(d); }
     void print_current_line(SearchStack ss[], int ply, int threadID);
@@ -2752,7 +2752,7 @@ namespace {
     AllThreadsShouldExit = true;
     for (int i = 1; i < THREAD_MAX; i++)
     {
-        threads[i].stop = true;
+        threads[i].stopRequest = true;
         while (threads[i].running);
     }
 
@@ -2774,7 +2774,7 @@ namespace {
 
     SplitPoint* sp;
 
-    if (threads[threadID].stop)
+    if (threads[threadID].stopRequest)
         return true;
 
     if (ActiveThreads <= 2)
@@ -2904,16 +2904,22 @@ namespace {
     for (int i = 0; i < ActiveThreads; i++)
         splitPoint->slaves[i] = 0;
 
-    threads[master].idle = false;
-    threads[master].stop = false;
     threads[master].splitPoint = splitPoint;
 
+    // If we are here it means we are not idle
+    assert(!threads[master].idle);
+
+    // Following assert could fail because we could be slave of a master
+    // thread that has just raised a stop request. Note that stopRequest
+    // can be changed with only splitPoint::lock held, not with MPLock.
+    /* assert(!threads[master].stopRequest); */
+
     // Allocate available threads setting idle flag to false
     for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
         if (thread_is_available(i, master))
         {
             threads[i].idle = false;
-            threads[i].stop = false;
+            threads[i].stopRequest = false;
             threads[i].splitPoint = splitPoint;
             splitPoint->slaves[i] = 1;
             splitPoint->cpus++;
@@ -2950,7 +2956,7 @@ namespace {
 
     *beta = splitPoint->beta;
     *bestValue = splitPoint->bestValue;
-    threads[master].stop = false;
+    threads[master].stopRequest = false;
     threads[master].idle = false;
     threads[master].activeSplitPoints--;
     threads[master].splitPoint = splitPoint->parent;
@@ -3006,11 +3012,20 @@ namespace {
 
     AllThreadsShouldSleep = true;
 
-    // Wait for the threads to be all sleeping
+    // Wait for the threads to be all sleeping and reset flags
+    // to a known state.
     for (int i = 1; i < ActiveThreads; i++)
+    {
         while (!threads[i].sleeping);
-  }
 
+        assert(threads[i].idle);
+        assert(threads[i].running);
+        assert(!threads[i].workIsWaiting);
+
+        // These two flags can be in a random state
+        threads[i].stopRequest = threads[i].printCurrentLineRequest = false;
+    }
+  }
 
   // print_current_line() prints _once_ the current line of search for a
   // given thread and then setup the print request for the next thread.