Robbie Gemmell created ARTEMIS-3591:
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Summary: PagingStoreImpl#checkMemory can run the provided task
more than once
Key: ARTEMIS-3591
URL: https://issues.apache.org/jira/browse/ARTEMIS-3591
Project: ActiveMQ Artemis
Issue Type: Bug
Components: Broker
Affects Versions: 2.19.0
Reporter: Robbie Gemmell
PagingStoreImpl#checkMemory takes a Runnable argument. It takes steps to ensure
that the given Runnable is an
org.apache.activemq.artemis.utils.runnables.AtomicRunnable, or wraps it as one,
before adding it to the 'onMemoryFreedRunnables' queue for later execution in
some cases.
There is a case where it does this and adds it to the queue
[[1]|https://github.com/apache/activemq-artemis/blob/f8472fd736eff21d21ca2ab0c5a4dd22f0f1d00e/artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/impl/PagingStoreImpl.java#L708],
but then checks the paging state again to guard against a race and can decide
to just run the action immediately
[[2]|https://github.com/apache/activemq-artemis/blob/f8472fd736eff21d21ca2ab0c5a4dd22f0f1d00e/artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/impl/PagingStoreImpl.java#L716].
However it uses the bare action to run it immediately, not the
potentially-wrapped version it added to the queue by this point. If the passed
Runnable was not already an AtomicRunnable, as it seems many wont be, then this
will mean the original action is likely to be run more than once, immediately
at this point and then again via the AtomicRunnable added to the queue (the
next time the queue is processed).
It should use a reference to the same AtomicRunnable object it adds to the
queue, ensuring the underlying task is either run immediately or later, and not
both. It could additionally try to remove the entry from the queue after
running it.
[1]
[https://github.com/apache/activemq-artemis/blob/f8472fd736eff21d21ca2ab0c5a4dd22f0f1d00e/artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/impl/PagingStoreImpl.java#L708]
[2]
[https://github.com/apache/activemq-artemis/blob/f8472fd736eff21d21ca2ab0c5a4dd22f0f1d00e/artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/impl/PagingStoreImpl.java#L716]
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