diff --git a/test/fuzz/test_runner.py b/test/fuzz/test_runner.py
index 0c45b9053..ff182c611 100755
--- a/test/fuzz/test_runner.py
+++ b/test/fuzz/test_runner.py
@@ -1,143 +1,147 @@
 #!/usr/bin/env python3
 # Copyright (c) 2019 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Run fuzz test targets.
 """
 
 import argparse
 import configparser
 import logging
 import os
 import subprocess
 import sys
 
 # Fuzzers known to lack a seed corpus in
 # https://github.com/Bitcoin-ABC/qa-assets/tree/master/fuzz_seed_corpus
 FUZZERS_MISSING_CORPORA = [
     "strprintf",
 ]
 
 
 def main():
     parser = argparse.ArgumentParser(
         formatter_class=argparse.ArgumentDefaultsHelpFormatter)
     parser.add_argument(
         "-l",
         "--loglevel",
         dest="loglevel",
         default="INFO",
         help="log events at this level and higher to the console. Can be set to DEBUG, INFO, WARNING, ERROR or CRITICAL. Passing --loglevel DEBUG will output all logs to console.",
     )
     parser.add_argument(
         '--export_coverage',
         action='store_true',
         help='If true, export coverage information to files in the seed corpus',
     )
     parser.add_argument(
         'seed_dir',
         help='The seed corpus to run on (must contain subfolders for each fuzz target).',
     )
     parser.add_argument(
         'target',
         nargs='*',
         help='The target(s) to run. Default is to run all targets.',
     )
 
     args = parser.parse_args()
 
     # Set up logging
     logging.basicConfig(
         format='%(message)s',
         level=int(args.loglevel) if args.loglevel.isdigit(
         ) else args.loglevel.upper(),
     )
 
     # Read config generated by configure.
     config = configparser.ConfigParser()
     configfile = os.path.abspath(os.path.dirname(__file__)) + "/../config.ini"
     config.read_file(open(configfile, encoding="utf8"))
 
     if not config["components"].getboolean("ENABLE_FUZZ"):
         logging.error("Must have fuzz targets built")
         sys.exit(1)
     test_dir = os.path.join(
         config["environment"]["BUILDDIR"], 'src', 'test', 'fuzz')
 
     # Build list of tests
     test_list_all = [
         f for f in os.listdir(test_dir)
         if os.path.isfile(os.path.join(test_dir, f)) and
         os.access(os.path.join(test_dir, f), os.X_OK)]
 
     if not test_list_all:
         logging.error("No fuzz targets found")
         sys.exit(1)
 
     logging.info("Fuzz targets found: {}".format(test_list_all))
 
     # By default run all
     args.target = args.target or test_list_all
     test_list_error = list(set(args.target).difference(set(test_list_all)))
     if test_list_error:
         logging.error(
             "Unknown fuzz targets selected: {}".format(test_list_error))
     test_list_selection = list(
         set(test_list_all).intersection(set(args.target)))
     if not test_list_selection:
         logging.error("No fuzz targets selected")
     logging.info("Fuzz targets selected: {}".format(test_list_selection))
 
     try:
         help_output = subprocess.run(
             args=[
                 os.path.join(test_dir, test_list_selection[0]),
                 '-help=1',
             ],
             timeout=1,
             check=True,
             stderr=subprocess.PIPE,
             universal_newlines=True,
         ).stderr
         if "libFuzzer" not in help_output:
             logging.error("Must be built with libFuzzer")
             sys.exit(1)
     except subprocess.TimeoutExpired:
         logging.error(
             "subprocess timed out: Currently only libFuzzer is supported")
         sys.exit(1)
 
     run_once(
         corpus=args.seed_dir,
         test_list=test_list_selection,
         test_dir=test_dir,
         export_coverage=args.export_coverage,
     )
 
 
 def run_once(*, corpus, test_list, test_dir, export_coverage):
     for t in test_list:
         corpus_path = os.path.join(corpus, t)
         if t in FUZZERS_MISSING_CORPORA:
             os.makedirs(corpus_path, exist_ok=True)
         args = [
             os.path.join(test_dir, t),
             '-runs=1',
             '-detect_leaks=0',
             corpus_path,
         ]
         logging.debug('Run {} with args {}'.format(t, args))
-        output = subprocess.run(
-            args, check=True, stderr=subprocess.PIPE, universal_newlines=True).stderr
+        result = subprocess.run(
+            args,
+            stderr=subprocess.PIPE,
+            universal_newlines=True)
+        output = result.stderr
         logging.debug('Output: {}'.format(output))
+        result.check_returncode()
         if not export_coverage:
             continue
         for line in output.splitlines():
             if 'INITED' in line:
                 with open(os.path.join(corpus, t + '_coverage'), 'w', encoding='utf-8') as cov_file:
                     cov_file.write(line)
                     break
 
 
 if __name__ == '__main__':
     main()