From 7c4ad6e2986907e621496cd992010b264b37c63c Mon Sep 17 00:00:00 2001
From: Eirik0 <eirik@z.cash>
Date: Tue, 16 Apr 2019 19:35:04 -0600
Subject: [PATCH] Additional locking and race condition prevention

---
 src/wallet/wallet.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 9c3107436..07fafe42f 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -606,6 +606,9 @@ void CWallet::RunSaplingMigration(int blockHeight) {
         saplingMigrationOperation = operation;
         q->addOperation(operation);
     } else if (blockHeight % 500 == 499) {
+        if (saplingMigrationOperation != nullptr) {
+            saplingMigrationOperation->cancel();
+        }
         for (const CTransaction& transaction : pendingSaplingMigrationTxs) {
             // The following is taken from z_sendmany/z_mergetoaddress
             // Send the transaction
@@ -623,6 +626,7 @@ void CWallet::RunSaplingMigration(int blockHeight) {
 }
 
 void CWallet::AddPendingSaplingMigrationTx(const CTransaction& tx) {
+    LOCK(cs_wallet);
     pendingSaplingMigrationTxs.push_back(tx);
 }