Merge pull request swiftlang#2646 from apple/lldb-Add-work-around-handling-of-recursive_mutex-lock-failures

[lldb] Add work around handling of recursive_mutex lock failures

Author: kastiglione

lldb/test/API/lldbtest.py

@@ -101,6 +101,19 @@ def execute(self, test, litConfig):
         if timeoutInfo:
             return lit.Test.TIMEOUT, output
 
+        # Temporary fix to a flaky CI error. See rdar://52221547
+        # After unit tests have finished, a race during lldb shutdown can
+        # result in this innocuous and trouble causing failure:
+        #
+        # libc++abi.dylib: terminating with uncaught exception of type \
+        # std::__1::system_error: recursive_mutex lock failed: Invalid argument
+        if (
+            'RESULT: PASSED' in err and
+            'recursive_mutex lock failed' in err and
+            exitCode != 0
+        ):
+            return lit.Test.FLAKYPASS, output
+
         if exitCode:
             if 'XPASS:' in out or 'XPASS:' in err:
                 return lit.Test.XPASS, output