1996fanrui opened a new pull request, #29053:
URL: https://github.com/apache/flink/pull/29053
## What is the purpose of the change
`RecoveredInputChannel.finishReadRecoveredState()` wrapped
`onRecoveredStateBuffer()` in
`synchronized(receivedBuffers)`, but that method already locks
`receivedBuffers` internally and, when the
queue was empty, calls `notifyChannelNonEmpty()`, which acquires
`inputChannelsWithData` while
`receivedBuffers` is still held. This inverts the task thread's
`inputChannelsWithData -> receivedBuffers`
lock order and can deadlock on the error path (ABBA). Removing the redundant
outer lock restores the correct
order with no behavior change, since `onRecoveredStateBuffer` already
provides the required mutual exclusion.
## Brief change log
- Drop the outer `synchronized(receivedBuffers)` in
`RecoveredInputChannel.finishReadRecoveredState()`.
## Verifying this change
This change is a trivial rework / code cleanup without any test coverage.
The ABBA cycle is an error-path
lock-ordering issue that cannot be reproduced deterministically in a unit
test; `onRecoveredStateBuffer`
retains its internal locking, so behavior is otherwise unchanged.
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): no
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: no
- The serializers: no
- The runtime per-record code paths (performance sensitive): no
- Anything that affects deployment or recovery: yes (input channel-state
recovery)
- The S3 file system connector: no
## Documentation
- Does this pull request introduce a new feature? no
- If yes, how is the feature documented? not applicable
---
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