On Thu, 20 Nov 2025 13:10:53 GMT, Daniel Fuchs <[email protected]> wrote:
> An experimental change to SelectorManager::shutdown unveiled a potential > deadlock between the SelectorManager thread trying to stop the > HttpClientImpl, and an executor thread concurrently trying to return a > connection to the pool. > > The issue seems to be caused by the ConnectionPool::returnToPool trying to > close the returned connection when stopping, while holding the ConnectionPool > state lock, and the SelectorManager thread trying to close a pooled > connection, holding the connection stateLock and trying to close the channel, > which caused the CleanupTrigger to fire and attempt to remove the connection > from the pool. > > This problem was observed once with the > java/net/httpclient/ThrowingSubscribersAsLimitingAsync.java test. > > To avoid the problem, the proposed fix is to wait until the > ConnectionPool::stateLock has been released before actually closing the > connection, and to wait until the PlainHttpConnection::stateLock has been > released before actually closing the channel. Indeed, there should be no need > to close those while holding the lock. > > This PR was recreated due to a bad merge pushed to > https://github.com/openjdk/jdk/pull/28421 This pull request has now been integrated. Changeset: 8a0672c8 Author: Daniel Fuchs <[email protected]> URL: https://git.openjdk.org/jdk/commit/8a0672c819e09a16c30fbdf58dc2b81f50958da4 Stats: 431 lines in 4 files changed: 406 ins; 9 del; 16 mod 8372198: Avoid closing PlainHttpConnection while holding a lock Reviewed-by: djelinski, jpai, vyazici ------------- PR: https://git.openjdk.org/jdk/pull/28430
