From d9b5ba2d1710d7f52536ab9c53c3a68329f61b90 Mon Sep 17 00:00:00 2001
From: Tess Avitabile <tess.avitabile@mongodb.com>
Date: Tue, 4 Sep 2018 11:50:10 -0400
Subject: SERVER-36975 Fix race condition in
 read_concern_snapshot_catalog_invalidation.js

---
 .../noPassthrough/read_concern_snapshot_catalog_invalidation.js  | 9 ++++++++-
 src/mongo/db/SConscript                                          | 1 +
 src/mongo/db/transaction_participant.cpp                         | 6 +++++-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/jstests/noPassthrough/read_concern_snapshot_catalog_invalidation.js b/jstests/noPassthrough/read_concern_snapshot_catalog_invalidation.js
index ad8ce3a6337..eefbe613f84 100644
--- a/jstests/noPassthrough/read_concern_snapshot_catalog_invalidation.js
+++ b/jstests/noPassthrough/read_concern_snapshot_catalog_invalidation.js
@@ -15,10 +15,17 @@
     const adminDB = testDB.getSiblingDB("admin");
     const coll = testDB.getCollection(kCollName);
 
+    // Waits for the operation to reach the "hangAfterPreallocateSnapshot" failpoint.
     function waitForOp(curOpFilter) {
         assert.soon(
             function() {
-                const res = adminDB.aggregate([{$currentOp: {}}, {$match: curOpFilter}]).toArray();
+                const res =
+                    adminDB
+                        .aggregate([
+                            {$currentOp: {}},
+                            {$match: {$and: [curOpFilter, {msg: "hangAfterPreallocateSnapshot"}]}}
+                        ])
+                        .toArray();
                 if (res.length === 1) {
                     return true;
                 }
diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index d327b38f363..7e83900541d 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -643,6 +643,7 @@ env.Library(
         'catalog/database_holder',
         'catalog/uuid_catalog',
         'concurrency/lock_manager',
+        'curop_failpoint_helpers',
         'curop_metrics',
         'dbdirectclient',
         'index/index_access_method',
diff --git a/src/mongo/db/transaction_participant.cpp b/src/mongo/db/transaction_participant.cpp
index ba01744fff4..b84088757a7 100644
--- a/src/mongo/db/transaction_participant.cpp
+++ b/src/mongo/db/transaction_participant.cpp
@@ -36,6 +36,7 @@
 #include "mongo/db/concurrency/d_concurrency.h"
 #include "mongo/db/concurrency/lock_state.h"
 #include "mongo/db/concurrency/locker.h"
+#include "mongo/db/curop_failpoint_helpers.h"
 #include "mongo/db/op_observer.h"
 #include "mongo/db/repl/repl_client_info.h"
 #include "mongo/db/server_parameters.h"
@@ -515,7 +516,10 @@ void TransactionParticipant::unstashTransactionResources(OperationContext* opCtx
 
     // The Client lock must not be held when executing this failpoint as it will block currentOp
     // execution.
-    MONGO_FAIL_POINT_PAUSE_WHILE_SET(hangAfterPreallocateSnapshot);
+    if (MONGO_FAIL_POINT(hangAfterPreallocateSnapshot)) {
+        CurOpFailpointHelpers::waitWhileFailPointEnabled(
+            &hangAfterPreallocateSnapshot, opCtx, "hangAfterPreallocateSnapshot");
+    }
 }
 
 Timestamp TransactionParticipant::prepareTransaction(OperationContext* opCtx) {
-- 
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