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https://issues.apache.org/jira/browse/IGNITE-18316?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Denis Chudov reassigned IGNITE-18316:
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Assignee: Denis Chudov
> Reusing same waiter for multiple acquisitions can lead to races due to future
> rewrite outside of synchronized section
> ---------------------------------------------------------------------------------------------------------------------
>
> Key: IGNITE-18316
> URL: https://issues.apache.org/jira/browse/IGNITE-18316
> Project: Ignite
> Issue Type: Bug
> Reporter: Denis Chudov
> Assignee: Denis Chudov
> Priority: Major
> Labels: ignite-3
>
> Under IGNITE-18294 reusable waiters in heap lock manager have been done. Each
> waiter has a {{fut}} field, storing lock future, which is completed when
> waiter can be locked, converting all of its lock intentions into actual
> locks. Only one future for all intentions can exist, this means that it will
> be completed when supremum of all lock intentions can be acquired. As the
> lock mode for the waiter can be upgraded multiple times, lock future can be
> created several times for the waiter, rewriting {{fut}} field.
> Waiter's thread safety is provided by synchronized section on the mutex which
> is waiters collection for the key. Meanwhile, lock future should be completed
> outside of this mutex, as there may be long running tasks created for
> {{thenComplete}} of this future. These tasks must be done outside of the
> mutex, otherwise performance of the lock manager will be poor.
> Obviously, assuming that future field can be rewritten inside of mutex at any
> time, we can't complete it safely outside of mutex.
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