Ticket #10770: deadlock1-0.25.patch

mythtv/programs/mythbackend/scheduler.cpp

@@ -690 +690 @@
     }
 
     EncoderLink *tv = (*m_tvList)[oldp->GetCardID()];
+    lockit.unlock();
     RecStatusType rs = tv->StartRecording(oldp);
+    lockit.relock();
     if (rs != rsRecording)
     {
         LOG(VB_GENERAL, LOG_ERR,
@@ -817 +819 @@
 
 void Scheduler::BuildWorkList(void)
 {
-    reclist_changed = false;
-
     RecIter i = reclist.begin();
     for (; i != reclist.end(); ++i)
     {
@@ -1795 +1795 @@
 
     while (doRun)
     {
+        reclist_changed = false;
+
         QDateTime curtime = QDateTime::currentDateTime();
         bool statuschanged = false;
         int secs_to_next = (startIter != reclist.end()) ?
@@ -1905 +1907 @@
                 **it, statuschanged, prerollseconds, tuningTimeout);
         }
 
+        // HandleRecording() and HandleTuning() temporarily unlocks
+        // schedLock.  If anything changed, reclist iterators could be
+        // invalidated so start over.
+        if (reclist_changed)
+            continue;
+
         /// Wake any slave backends that need waking
         curtime = QDateTime::currentDateTime();
         for (RecIter it = startIter; it != reclist.end(); ++it)
@@ -2283 +2291 @@
     if (ri.GetRecordingStatus() == rsTuning)
     {
         HandleTuning(ri, statuschanged, tuningTimeout);
-        return false;
+        return reclist_changed;
     }
 
     if (ri.GetRecordingStatus() != rsWillRecord)
@@ -2351 +2359 @@
         return false;
     }
 
-    if ((prerollseconds > 0) && !IsBusyRecording(&ri))
+    schedLock.unlock();
+    bool isBusyRecording = IsBusyRecording(&ri);
+    schedLock.lock();
+    if (reclist_changed)
+        return reclist_changed;
+
+    if ((prerollseconds > 0) && !isBusyRecording)
     {
         // Will use pre-roll settings only if no other
         // program is currently being recorded
@@ -2444 +2458 @@
     {
         if (ri.GetRecordingStatus() == rsWillRecord)
         {
+            schedLock.unlock();
             recStatus = nexttv->StartRecording(&ri);
-            ri.AddHistory(false);
+            schedLock.lock();
 
             // activate auto expirer
             if (m_expirer)
@@ -2456 +2471 @@
     HandleRecordingStatusChange(ri, recStatus, details);
     statuschanged = true;
 
-    return false;
+    return reclist_changed;
 }
 
 void Scheduler::HandleRecordingStatusChange(
@@ -2467 +2482 @@
 
     ri.SetRecordingStatus(recStatus);
 
-    if (rsTuning != recStatus)
-    {
-        bool doSchedAfterStart =
-            ((rsRecording != recStatus) && (rsTuning != recStatus)) ||
-            schedAfterStartMap[ri.GetRecordingRuleID()] ||
-            (ri.GetParentRecordingRuleID() &&
-             schedAfterStartMap[ri.GetParentRecordingRuleID()]);
-        ri.AddHistory(doSchedAfterStart);
-    }
+    bool doSchedAfterStart =
+        recStatus != rsTuning &&
+        (recStatus != rsRecording ||
+         schedAfterStartMap[ri.GetRecordingRuleID()] ||
+         (ri.GetParentRecordingRuleID() &&
+          schedAfterStartMap[ri.GetParentRecordingRuleID()]));
+    ri.AddHistory(doSchedAfterStart);
 
     QString msg = (rsRecording == recStatus) ?
         QString("Started recording") :
@@ -2516 +2529 @@
     }
     else if (tuningTimeout > 0)
     {
+        schedLock.unlock();
         recStatus = (*tvit)->GetRecordingStatus();
+        schedLock.lock();
+        if (reclist_changed)
+            return;
+
         if (rsTuning == recStatus)
         {
             // If tuning is still taking place this long after we