fix some locking issues

arangod/Agency/Agent.cpp

@@ -299,12 +299,13 @@ void Agent::sendAppendEntriesRPC() {
 
       term_t t(0);
 
+      index_t last_confirmed;
       {
         MUTEX_LOCKER(mutexLocker, _ioLock);
         t = this->term();
+        last_confirmed = _confirmed[followerId];
       }
 
-      index_t last_confirmed = _confirmed[followerId];
       std::vector<log_t> unconfirmed = _state.get(last_confirmed);
 
       if (unconfirmed.empty()) {

arangod/Agency/AgentConfiguration.cpp

@@ -77,6 +77,9 @@ config_t::config_t(config_t&& other)
       _supervisionGracePeriod(std::move(other._supervisionGracePeriod)) {}
 
 config_t& config_t::operator=(config_t const& other) {
+  // must hold the lock of other to copy _pool, _minPing, _maxPing etc.
+  READ_LOCKER(readLocker, other._lock);
+
   _id = other._id;
   _agencySize = other._agencySize;
   _poolSize = other._poolSize;

arangod/Agency/Store.cpp

@@ -178,7 +178,10 @@ std::vector<bool> Store::apply(query_t const& query, bool verbose) {
       }
 
       // Wake up TTL processing
-      _cv.signal();
+      {
+        CONDITION_LOCKER(guard, _cv);
+        _cv.signal();
+      }
 
     } catch (std::exception const& e) {  // Catch any erorrs
       LOG_TOPIC(ERR, Logger::AGENCY) << __FILE__ << ":" << __LINE__ << " "
@@ -503,7 +506,6 @@ bool Store::start() {
 
 /// Work ttls and callbacks
 void Store::run() {
-  CONDITION_LOCKER(guard, _cv);
   while (!this->isStopping()) {  // Check timetable and remove overage entries
 
     std::chrono::microseconds t{0};
@@ -517,10 +519,13 @@ void Store::run() {
       }
     }
 
-    if (t != std::chrono::microseconds{0}) {
-      _cv.wait(t.count());
-    } else {
-      _cv.wait();
+    {
+      CONDITION_LOCKER(guard, _cv);
+      if (t != std::chrono::microseconds{0}) {
+        _cv.wait(t.count());
+      } else {
+        _cv.wait();
+      }
     }
 
     toClear = clearExpired();