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ASF GitHub Bot commented on FLINK-9676: --------------------------------------- Github user pnowojski commented on the issue: https://github.com/apache/flink/pull/6254 Please document in java doc AND in the commit message the contract of lock hierarchy that you are implementing here. > Deadlock during canceling task and recycling exclusive buffer > ------------------------------------------------------------- > > Key: FLINK-9676 > URL: https://issues.apache.org/jira/browse/FLINK-9676 > Project: Flink > Issue Type: Bug > Components: Network > Affects Versions: 1.5.0 > Reporter: zhijiang > Assignee: Nico Kruber > Priority: Critical > Labels: pull-request-available > Fix For: 1.6.0, 1.5.1 > > > It may cause deadlock between task canceler thread and task thread. > The detail is as follows: > {{Task canceler thread -> IC1#releaseAllResources -> recycle floating buffers > -> {color:#d04437}lock{color}(LocalBufferPool#availableMemorySegments) -> > IC2#notifyBufferAvailable}} > {color:#d04437}try to > lock{color}(IC2#bufferQueue) > {{Task thread -> IC2#recycle -> {color:#d04437}lock{color}(IC2#bufferQueue) > -> bufferQueue#addExclusiveBuffer}} -> {{floatingBuffer#recycleBuffer}} -> > {color:#d04437}try to lock{color}(LocalBufferPool#availableMemorySegments) > One solution is that {{listener#notifyBufferAvailable}} can be called outside > the {{synchronized(availableMemorySegments) in }}{{LocalBufferPool#recycle.}} > The existing RemoteInputChannelTest#testConcurrentOnSenderBacklogAndRecycle > can cover this case but the deadlock probability is very low, so this UT is > not stable. -- This message was sent by Atlassian JIRA (v7.6.3#76005)