From fa31c4daac5629d14360bbe9b2cd98db4c083989 Mon Sep 17 00:00:00 2001
From: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>
Date: Tue, 20 Jun 2023 18:22:43 +0200
Subject: [PATCH] fuzz: Avoid OOM in transaction fuzz target

Also fix bug where the json object is reused between two calls.
---
 src/test/fuzz/transaction.cpp | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/test/fuzz/transaction.cpp b/src/test/fuzz/transaction.cpp
index 7035c53d13..c561675d1a 100644
--- a/src/test/fuzz/transaction.cpp
+++ b/src/test/fuzz/transaction.cpp
@@ -101,7 +101,14 @@ FUZZ_TARGET_INIT(transaction, initialize_transaction)
     (void)AreInputsStandard(tx, coins_view_cache);
     (void)IsWitnessStandard(tx, coins_view_cache);
 
-    UniValue u(UniValue::VOBJ);
-    TxToUniv(tx, /*block_hash=*/uint256::ZERO, /*entry=*/u);
-    TxToUniv(tx, /*block_hash=*/uint256::ONE, /*entry=*/u);
+    if (tx.GetTotalSize() < 250'000) { // Avoid high memory usage (with msan) due to json encoding
+        {
+            UniValue u{UniValue::VOBJ};
+            TxToUniv(tx, /*block_hash=*/uint256::ZERO, /*entry=*/u);
+        }
+        {
+            UniValue u{UniValue::VOBJ};
+            TxToUniv(tx, /*block_hash=*/uint256::ONE, /*entry=*/u);
+        }
+    }
 }