--- a/testing/mozharness/mozharness/mozilla/testing/errors.py
+++ b/testing/mozharness/mozharness/mozilla/testing/errors.py
@@ -110,16 +110,17 @@ TinderBoxPrintRe = {
 
 TestPassed = [
     {'regex': re.compile('''(TEST-INFO|TEST-KNOWN-FAIL|TEST-PASS|INFO \| )'''), 'level': INFO},
 ]
 
 HarnessErrorList = [
     {'substr': 'TEST-UNEXPECTED', 'level': ERROR, },
     {'substr': 'PROCESS-CRASH', 'level': ERROR, },
+    {'regex': re.compile('''thread '([^']+)' panicked'''), 'level': ERROR, },
 ]
 
 LogcatErrorList = [
     {'substr': 'Fatal signal 11 (SIGSEGV)', 'level': ERROR, 'explanation': 'This usually indicates the B2G process has crashed'},
     {'substr': 'Fatal signal 7 (SIGBUS)', 'level': ERROR, 'explanation': 'This usually indicates the B2G process has crashed'},
     {'substr': '[JavaScript Error:', 'level': WARNING},
     {'substr': 'seccomp sandbox violation', 'level': ERROR, 'explanation': 'A content process has violated the system call sandbox (bug 790923)'},
 ]