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https://issues.apache.org/jira/browse/FLINK-40525?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-40525:
-----------------------------------
Labels: pull-request-available (was: )
> RecoveredInputChannel.finishReadRecoveredState holds receivedBuffers across
> notifyChannelNonEmpty, risking an ABBA deadlock
> ---------------------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-40525
> URL: https://issues.apache.org/jira/browse/FLINK-40525
> Project: Flink
> Issue Type: Sub-task
> Components: Runtime / Checkpointing
> Reporter: Rui Fan
> Assignee: Rui Fan
> Priority: Major
> Labels: pull-request-available
>
> `finishReadRecoveredState` wraps its `onRecoveredStateBuffer` call in an
> extra `synchronized (receivedBuffers)` [1]. On the `wasEmpty` branch that
> call reaches `notifyChannelNonEmpty()` → `SingleInputGate.queueChannel`,
> which takes `inputChannelsWithData` — so the IO thread holds
> `receivedBuffers` and then acquires `inputChannelsWithData`. The task thread
> does the reverse: `waitAndGetNextData` holds `inputChannelsWithData` and then
> acquires `receivedBuffers` via `isReleased()`. When a channel is enqueued
> while its `receivedBuffers` is empty (e.g. `setError` from
> `BufferManager.notifyBufferAvailable`'s catch enqueues without adding a
> buffer), the ABBA cycle closes: task holds `inputChannelsWithData` waiting on
> `receivedBuffers`, IO holds `receivedBuffers` waiting on
> `inputChannelsWithData`.
> Fix: remove the outer `synchronized`, which is safe because
> `onRecoveredStateBuffer` already locks `receivedBuffers` internally around
> the actual add — the collection stays protected, and the outer lock only
> served to hold it across `notifyChannelNonEmpty`, which is exactly what
> inverts the lock order.
> [1]
> [https://github.com/apache/flink/blob/76e774e04ff84ea305714153c5f4790fff98437c/flink-runtime/src/main/java/org/apache/flink/runtime/io/network/partition/consumer/RecoveredInputChannel.java#L163-L170]
>
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