Use reader writer lock guard for CRT logger instance pointer access #2552
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SergeyRyabinin
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jeking3
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| @@ -35,7 +38,11 @@ static int s_aws_logger_redirect_log( | |||
| { | |||
| AWS_UNREFERENCED_PARAM(logger); | |||
| // use local variable because global variable can be modified in the middle by another thread. | |||
| std::shared_ptr<CRTLogSystemInterface> localCRTLogSystem = CRTLogSystem; | |||
| std::shared_ptr<CRTLogSystemInterface> localCRTLogSystem; | |||
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The Reader lock allows this variable to be removed, avoid a copy, and just access CRTLogSystem directly in the four logging methods as long as the shared lock is held onto.
jeking3
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Jul 6, 2023
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I tested this change with valgrind/drd, which does not understand the ReaderWriterLock protection. It would need DRD annotations (https://valgrind.org/docs/manual/drd-manual.html#drd-manual.effective-use, section 8.2.5) to understand the safety scoping being provided.
I changed a local copy to use std::mutex and it passed through valgrind/drd successfully, whereas without there was a thread safety issue.
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