IllegalMonitorStateException 2.x

[DavidDTA]

RxJava version 2.2.12.
Android 8 and 9, and 5, disproportionately uncommon on Samsung devices.

Stack trace:

Caused by java.lang.IllegalMonitorStateException
       at java.util.concurrent.locks.ReentrantLock$Sync.tryRelease + 152(ReentrantLock.java:152)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer.release + 1285(AbstractQueuedSynchronizer.java:1285)
       at java.util.concurrent.locks.ReentrantLock.unlock + 458(ReentrantLock.java:458)
       at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.offer + 1067(ScheduledThreadPoolExecutor.java:1067)
       at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.add + 1077(ScheduledThreadPoolExecutor.java:1077)
       at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.add + 1076(ScheduledThreadPoolExecutor.java:1076)
       at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute + 336(ScheduledThreadPoolExecutor.java:336)
       at java.util.concurrent.ScheduledThreadPoolExecutor.schedule + 579(ScheduledThreadPoolExecutor.java:579)
       at java.util.concurrent.ScheduledThreadPoolExecutor.submit + 680(ScheduledThreadPoolExecutor.java:680)
       at io.reactivex.internal.schedulers.NewThreadWorker.scheduleActual + 145(NewThreadWorker.java:145)
       at io.reactivex.internal.schedulers.ComputationScheduler$EventLoopWorker.schedule + 227(ComputationScheduler.java:227)
       at io.reactivex.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.trySchedule + 166(FlowableObserveOn.java:166)
       at io.reactivex.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.onNext + 117(FlowableObserveOn.java:117)
       at io.reactivex.internal.operators.flowable.FlowableHide$HideSubscriber.onNext + 68(FlowableHide.java:68)
       at io.reactivex.internal.operators.flowable.FlowableOnBackpressureBuffer$BackpressureBufferSubscriber.drain + 187(FlowableOnBackpressureBuffer.java:187)
       at io.reactivex.internal.operators.flowable.FlowableOnBackpressureBuffer$BackpressureBufferSubscriber.onNext + 112(FlowableOnBackpressureBuffer.java:112)
       at io.reactivex.internal.operators.flowable.FlowableMap$MapSubscriber.onNext + 68(FlowableMap.java:68)
       at io.reactivex.processors.BehaviorProcessor$BehaviorSubscription.test + 640(BehaviorProcessor.java:640)
       at io.reactivex.processors.BehaviorProcessor$BehaviorSubscription.emitNext + 620(BehaviorProcessor.java:620)
       at io.reactivex.processors.BehaviorProcessor.onNext + 281(BehaviorProcessor.java:281)
       at io.reactivex.processors.SerializedProcessor.onNext + 103(SerializedProcessor.java:103)
       at io.reactivex.internal.operators.flowable.FlowableScanSeed$ScanSeedSubscriber.drain + 207(FlowableScanSeed.java:207)
       at io.reactivex.internal.operators.flowable.FlowableScanSeed$ScanSeedSubscriber.onNext + 123(FlowableScanSeed.java:123)
       at io.reactivex.internal.operators.flowable.FlowableOnBackpressureBuffer$BackpressureBufferSubscriber.drain + 187(FlowableOnBackpressureBuffer.java:187)
       at io.reactivex.internal.operators.flowable.FlowableOnBackpressureBuffer$BackpressureBufferSubscriber.onNext + 112(FlowableOnBackpressureBuffer.java:112)
       at io.reactivex.processors.PublishProcessor$PublishSubscription.onNext + 360(PublishProcessor.java:360)
       at io.reactivex.processors.PublishProcessor.onNext + 243(PublishProcessor.java:243)
       at io.reactivex.processors.SerializedProcessor.onNext + 103(SerializedProcessor.java:103)
       <redacted application frames>
       at io.reactivex.internal.operators.flowable.FlowableUsing.subscribeActual + 49(FlowableUsing.java:49)
       at io.reactivex.Flowable.subscribe + 14918(Flowable.java:14918)
       at io.reactivex.Flowable.subscribe + 14865(Flowable.java:14865)
       at io.reactivex.internal.operators.flowable.FlowableSwitchMap$SwitchMapSubscriber.onNext + 129(FlowableSwitchMap.java:129)
       at io.reactivex.internal.operators.flowable.FlowableDistinctUntilChanged$DistinctUntilChangedSubscriber.tryOnNext + 101(FlowableDistinctUntilChanged.java:101)
       at io.reactivex.internal.operators.flowable.FlowableDistinctUntilChanged$DistinctUntilChangedSubscriber.onNext + 67(FlowableDistinctUntilChanged.java:67)
       at io.reactivex.internal.operators.flowable.FlowableMap$MapConditionalSubscriber.onNext + 111(FlowableMap.java:111)
       at io.reactivex.internal.operators.flowable.FlowableDistinctUntilChanged$DistinctUntilChangedConditionalSubscriber.tryOnNext + 191(FlowableDistinctUntilChanged.java:191)
       at io.reactivex.internal.operators.flowable.FlowableMap$MapConditionalSubscriber.tryOnNext + 128(FlowableMap.java:128)
       at io.reactivex.internal.operators.flowable.FlowableObserveOn$ObserveOnConditionalSubscriber.runAsync + 649(FlowableObserveOn.java:649)
       at io.reactivex.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.run + 176(FlowableObserveOn.java:176)
       at io.reactivex.android.schedulers.HandlerScheduler$ScheduledRunnable.run + 124(HandlerScheduler.java:124)
       at android.os.Handler.handleCallback + 794(Handler.java:794)
       at android.os.Handler.dispatchMessage + 99(Handler.java:99)
       at android.os.Looper.loop + 176(Looper.java:176)
       at android.app.ActivityThread.main + 6635(ActivityThread.java:6635)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run + 547(RuntimeInit.java:547)
       at com.android.internal.os.ZygoteInit.main + 823(ZygoteInit.java:823)

As background information, the Flowable involved in this chain has the hide operation as a workaround for #6673 as recommended in the discussion of #5927.

This crash is at a much lower volume that the one tracked in #6673.

[akarnokd]

This looks like a bug with the underlying java.util.concurrent.ScheduledThreadPoolExecutor implementation for that particular runtime. We are using only standard Java APIs and can't do anything about it and can't offer any workarounds.

[DavidDTA]

Indeed, the documentation for ScheduledThreadPoolExecutor.submit does not document that it can throw java.lang.IllegalMonitorStateException. Thanks for the quick response.