Bugfix: race condition between bootstrap pull and push #3720
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dsiganos
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The unit test bootstrap_processor.push_one fails intermittently and it exposes a race condition in the bootstrap code of the node. nanocurrency#3533 The race condition is that after finishing with bootstrap frontiers pull, the code is supposed to put the socket back into the idle bootstrap connections queue. However it does that in a racy way. The problem is in the function nano::frontier_req_client::received_frontier. Near the bottom of that function, we should call: connection->connections.pool_connection (connection); before calling promise.set_value (false); Once the promise is given a value then nano::bootstrap_attempt_legacy::run() continues to call push_request in parallel with pool_connection and it is a race condition. Although this is a bug, this is likely not a major nor catastrophic bug because the bootstrap push functionality is only an efficiency. resolves nanocurrency#3533 resolves nanocurrency#3720
dsiganos
added a commit
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Feb 8, 2022
The unit test bootstrap_processor.push_one fails intermittently and it exposes a race condition in the bootstrap code of the node. #3533 The race condition is that after finishing with bootstrap frontiers pull, the code is supposed to put the socket back into the idle bootstrap connections queue. However it does that in a racy way. The problem is in the function nano::frontier_req_client::received_frontier. Near the bottom of that function, we should call: connection->connections.pool_connection (connection); before calling promise.set_value (false); Once the promise is given a value then nano::bootstrap_attempt_legacy::run() continues to call push_request in parallel with pool_connection and it is a race condition. Although this is a bug, this is likely not a major nor catastrophic bug because the bootstrap push functionality is only an efficiency. resolves #3533 resolves #3720
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The unit
test bootstrap_processor.push_onefails intermittently and it exposes a race condition in the bootstrap code of the node.#3533
The race condition is that after finishing with bootstrap frontiers pull, the code is supposed to put the socket back into the idle boostrap connections queue. However it does that in a racy way. The problem is in function
nano::frontier_req_client::received_frontier.Near the bottom of that function, we should call:
connection->connections.pool_connection (connection);before calling
promise.set_value (false);Once the promise is given a value then nano::bootstrap_attempt_legacy::run continues to call push_request in parallel with pool_connection and it is a race condition.
Although this is a bug, this is likely not a major nor catastrophic bug because the bootstrap functionality is only an efficiency.
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