SERVER-50869 Fix race condition in bgsync when clearing appliedThrough during stepUp

(cherry picked from commit 4fbb1f65e2ad712f6b4e761d3145191e744b1e7d)

1 files changed, 16 insertions, 0 deletions

diff --git a/src/mongo/db/repl/bgsync.cpp b/src/mongo/db/repl/bgsync.cpp
index 0a30d72803a..6867269f138 100644
--- a/src/mongo/db/repl/bgsync.cpp
+++ b/src/mongo/db/repl/bgsync.cpp
@@ -40,6 +40,7 @@
 #include "mongo/bson/util/bson_extract.h"
 #include "mongo/client/connection_pool.h"
 #include "mongo/db/auth/authorization_session.h"
+#include "mongo/db/catalog_raii.h"
 #include "mongo/db/client.h"
 #include "mongo/db/concurrency/replication_state_transition_lock_guard.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
@@ -50,6 +51,7 @@
 #include "mongo/db/repl/oplog_interface_local.h"
 #include "mongo/db/repl/oplog_interface_remote.h"
 #include "mongo/db/repl/repl_server_parameters_gen.h"
+#include "mongo/db/repl/replication_consistency_markers_impl.h"
 #include "mongo/db/repl/replication_coordinator.h"
 #include "mongo/db/repl/replication_coordinator_impl.h"
 #include "mongo/db/repl/replication_process.h"
@@ -485,6 +487,20 @@ void BackgroundSync::_produce() {
     // before the OplogWriter gets a chance to append to the oplog.
     {
         auto opCtx = cc().makeOperationContext();
+
+        // Check if the producer has been stopped so that we can prevent setting the applied point
+        // after step up has already cleared it. We need to acquire the collection lock before the
+        // mutex to preserve proper lock ordering.
+        AutoGetCollection autoColl(
+            opCtx.get(),
+            NamespaceString(ReplicationConsistencyMarkersImpl::kDefaultMinValidNamespace),
+            MODE_IX);
+        stdx::lock_guard<Latch> lock(_mutex);
+
+        if (_state != ProducerState::Running) {
+            return;
+        }
+
         if (_replicationProcess->getConsistencyMarkers()->getAppliedThrough(opCtx.get()).isNull()) {
             _replicationProcess->getConsistencyMarkers()->setAppliedThrough(
                 opCtx.get(), _replCoord->getMyLastAppliedOpTime());