logging: fix race condition in changing the logger #891
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This condition was found via clang TSAN analyzer. aws_logger_set/get operate on a global variable, but the operation on the shared global variable is not thread-safe. Use a mutex to avoid the race condition.
| result = s_root_logger_ptr; | ||
| aws_mutex_unlock(&s_root_logger_lock); | ||
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| return result; |
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This returns a pointer to the aws_logger(). The pointer can still access the underlying data in such a way that introduces a data race.
struct aws_logger * logger = aws_logger_get();
logger->foo = xx;
Since this can still race, AWS needs to provide a better solution here, whereby the API is changed to return a copy.
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Hi Gerrit, Thank you for the contribution. This API is not thread safe and must only be called once. Please feel free to reopen the PR if there is anything else. aws-c-common/include/aws/common/logging.h Line 222 in 4b4675c |
This is a very old PR. The condition occurred when To avoid that problem, we have been using a dedicated initializer thread, which takes care of calling Should the problem re-occur, I will create an issue. |
…be called from the same thread Running InitAPI() and ShutdownAPI() from different threads can cause subtle problems, see e.g. - aws/s2n-tls#3525 - awslabs/aws-c-common#891 Add a note for users to use the same thread.
…be called from the same thread Running InitAPI() and ShutdownAPI() from different threads can cause subtle problems, see e.g. - aws/s2n-tls#3525 - awslabs/aws-c-common#891 Add a note for users to use the same thread.
…be called from the same thread Running InitAPI() and ShutdownAPI() from different threads can cause subtle problems, see e.g. - aws/s2n-tls#3525 - awslabs/aws-c-common#891 Add a note for users to use the same thread.
This race condition was found via clang TSAN analyzer.
aws_logger_set/getoperate on a global variable, but the operation on the shared global variable is not thread-safe.Use a
mutexto avoid the race condition.By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.