Reverse lock order to avoid deadlock #256
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
In class AutorecoveringConnection: maybeDeleteRecordedAutoDeleteExchange takes the locks on - recordedExchanges - consumers maybeDeleteRecordedAutoDeleteQueue takes the locks on - recordedQueues - consumers Since the latter one also calls the former, the following deadlock may occur Thread1: maybeDeleteRecordedAutoDeleteExchange - locked recordedExchanges - waiting for consumers (locked by thread2) Thread2: maybeDeleteRecordedAutoDeleteQueue - locked recordedQueues - locked consumers maybeDeleteRecordedAutoDeleteExchange - waiting for recordedExchanges (locked by thread1) By reversing the locks, both flows will first lock consumers, avoiding taking other locks in a different order
|
Thank you, we are discussing it with @acogoluegnes. Curiously I see that it has been addressed in master but uses a different order. |
michaelklishin
approved these changes
Mar 3, 2017
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
In class AutorecoveringConnection:
maybeDeleteRecordedAutoDeleteExchange takes the locks on
maybeDeleteRecordedAutoDeleteQueue takes the locks on
Since the latter one also calls the former, the following deadlock may occur
Thread1:
maybeDeleteRecordedAutoDeleteExchange
Thread2:
maybeDeleteRecordedAutoDeleteQueue
maybeDeleteRecordedAutoDeleteExchange
By reversing the locks, both flows will first lock consumers, avoiding taking other locks
in a different order