From c054cddfe54ebd09a505c293cc0e3b3cd761faf1 Mon Sep 17 00:00:00 2001
From: Jan <jsteemann@users.noreply.github.com>
Date: Fri, 26 Apr 2019 18:31:24 +0200
Subject: [PATCH] fix race in _batchPingTimer shutdown (#8801)

---
 arangod/Replication/InitialSyncer.cpp | 18 ++++++++++++------
 arangod/Replication/InitialSyncer.h   |  1 +
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/arangod/Replication/InitialSyncer.cpp b/arangod/Replication/InitialSyncer.cpp
index cc9bf91d85..021971ea55 100644
--- a/arangod/Replication/InitialSyncer.cpp
+++ b/arangod/Replication/InitialSyncer.cpp
@@ -54,13 +54,19 @@ void InitialSyncer::startRecurringBatchExtension() {
   if (secs < 30) {
     secs = 30;
   }
+        
+  std::weak_ptr<Syncer> self(shared_from_this());
   _batchPingTimer = SchedulerFeature::SCHEDULER->queueDelay(
-      RequestLane::SERVER_REPLICATION, std::chrono::seconds(secs), [this](bool cancelled) {
-        if (!cancelled && _batch.id != 0 && !isAborted()) {
-          _batch.extend(_state.connection, _progress);
-          startRecurringBatchExtension();
-        } else {
-          _batchPingTimer.reset();
+      RequestLane::SERVER_REPLICATION, std::chrono::seconds(secs), [self](bool cancelled) {
+        if (!cancelled) {
+          auto syncer = self.lock();
+          if (syncer) {
+            InitialSyncer* s = static_cast<InitialSyncer*>(syncer.get());
+            if (s->_batch.id != 0 && !s->isAborted()) {
+              s->_batch.extend(s->_state.connection, s->_progress);
+              s->startRecurringBatchExtension();
+            }
+          }
         }
       });
 }
diff --git a/arangod/Replication/InitialSyncer.h b/arangod/Replication/InitialSyncer.h
index cf09412781..e82cbead31 100644
--- a/arangod/Replication/InitialSyncer.h
+++ b/arangod/Replication/InitialSyncer.h
@@ -94,6 +94,7 @@ class InitialSyncer : public Syncer {
  protected:
   replutils::BatchInfo _batch;
   replutils::ProgressInfo _progress;
+  
   /// recurring task to keep the batch alive
   Scheduler::WorkHandle _batchPingTimer;
 };