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https://issues.apache.org/jira/browse/IGNITE-23381?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17887338#comment-17887338
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Roman Puchkovskiy commented on IGNITE-23381:
--------------------------------------------
When an async write lock attempt adds a future (as it cannot acquire the lock
right away), we use double-checked locking to make sure we don't miss the
'write lock is available' state due to concurrent unlocking. If on that second
attempt we actually acquire the lock, we decrement the pendingWriteLocks
counter and proceed with the completion of the future.
The problem is that the same logic (acquisition of the lock, decrement and
future completion) might be invoked for the same future by the thread that
unlocks the previously held write lock. It might happen that those 2 threads
both do the following:
# Acquire the write lock (second time for this acquisition intent)
# Decrement the counter
But the future is completed only once (we try to complete it twice, but it
protects itself from invoking its callbacks twice), so the release of the write
lock (which is done by a callback following the future) happens only once. This
leaves the lock in an inconsistent state (it's write-locked instead of not
being write locked, and its pending write locks counter exceeds the value it
should have).
We should only allow one of the participants to perform these actions.
> VersatileReadWriteLockTest is flaky
> -----------------------------------
>
> Key: IGNITE-23381
> URL: https://issues.apache.org/jira/browse/IGNITE-23381
> Project: Ignite
> Issue Type: Bug
> Reporter: Roman Puchkovskiy
> Assignee: Roman Puchkovskiy
> Priority: Major
> Labels: ignite-3
>
> multipleInWriteLockAsyncAttemptsTakeWriteLockAfterImpedingLocksGetReleased(READ_LOCK)
> failed.
> Locally, I can reproduce its failures rather easily (from dozens to a few
> hundred runs are enough).
>
> java.lang.AssertionError: java.util.concurrent.ExecutionException:
> java.lang.AssertionError
> at
> org.apache.ignite.internal.testframework.matchers.CompletableFutureMatcher.matchesSafely(CompletableFutureMatcher.java:78)
> at
> org.apache.ignite.internal.testframework.matchers.CompletableFutureMatcher.matchesSafely(CompletableFutureMatcher.java:35)
> at org.hamcrest.TypeSafeMatcher.matches(TypeSafeMatcher.java:83)
> at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:10)
> at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:6)
> at
> org.apache.ignite.internal.util.VersatileReadWriteLockTest.multipleInWriteLockAsyncAttemptsTakeWriteLockAfterImpedingLocksGetReleased(VersatileReadWriteLockTest.java:522)
> at java.base/java.lang.reflect.Method.invoke(Method.java:566)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
> at
> java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
> at
> java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
> at
> java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
> at
> java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
> at
> java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
> at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
> at
> java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
> at
> java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
> at
> java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
> at
> java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
> at
> java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
> at
> java.base/java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:274)
> at
> java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655)
> at
> java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
> at
> java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
> at
> java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
> at
> java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
> at
> java.base/java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:274)
> at
> java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
> at
> java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
> at
> java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
> at
> java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655)
> at
> java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
> at
> java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
> at
> java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
> at
> java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
> at
> java.base/java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:274)
> at
> java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655)
> at
> java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
> at
> java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
> at
> java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
> at
> java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
> at
> java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
> at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
> at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
> Caused by: java.util.concurrent.ExecutionException: java.lang.AssertionError
> at
> java.base/java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:395)
> at
> java.base/java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2022)
> at
> org.apache.ignite.internal.testframework.matchers.CompletableFutureMatcher.matchesSafely(CompletableFutureMatcher.java:74)
> ... 52 more
> Caused by: java.lang.AssertionError
> at
> org.apache.ignite.internal.util.VersatileReadWriteLock.decrementPendingWriteLocks(VersatileReadWriteLock.java:268)
> at
> org.apache.ignite.internal.util.VersatileReadWriteLock.notifyWriteLockSolicitors(VersatileReadWriteLock.java:372)
> at
> org.apache.ignite.internal.util.VersatileReadWriteLock.writeUnlock(VersatileReadWriteLock.java:355)
> at
> org.apache.ignite.internal.util.VersatileReadWriteLock.lambda$inWriteLockAsync$5(VersatileReadWriteLock.java:450)
> at
> java.base/java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:859)
> at
> java.base/java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:837)
> at
> java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
> at
> java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073)
> at
> org.apache.ignite.internal.util.VersatileReadWriteLock.lambda$notifyWriteLockSolicitors$0(VersatileReadWriteLock.java:374)
> at
> java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
> at
> java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
> at java.base/java.lang.Thread.run(Thread.java:834)
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