System.StackOverflowException (due to Observable.Generate ?)

[valeriob]

Hi,
unfortunately it's hard to reproduce, but when i dispose this observable sometimes it result in a stackoverflow exception, and the whole process gets killed :(

Here is the setup of the observable :

var start = DateTime.Now.Trim(TimeSpan.TicksPerSecond).AddSeconds(1);
var boundary = Observable.Generate(
            0, _ => true, // start condition
            i => ++i,     // iterate
            i => i,       // result selector
            i => start + TimeSpan.FromSeconds(i));

 var merged = boundary.WithLatestFrom(SomeOtherObservable, (a, b) => b) ;
// here  i combine it with some other observables via WithLatestFrom 
 merged.Subscribe(m => { });

This is the stack trace i got from windbg :

0000007B1A67AC70 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67ACA0 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67ACD0 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67AD00 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67AD30 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67AD60 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67AD90 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67ADC0 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67ADF0 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67AE20 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67AE50 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67AE80 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67AEB0 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67AEE0 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67AF10 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67AF40 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67AF70 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67AFA0 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67AFD0 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67B000 00007ffbf668aeef System.Reactive.Concurrency.LocalScheduler+WorkItem.Dispose() 0000007B1A67B030 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67B060 00007ffbf66ffcbc System.Reactive.Concurrency.UserWorkItem1[[System.ValueTuple2[[System.__Canon, System.Private.CoreLib],[System.Int32, System.Private.CoreLib]], System.Private.CoreLib]].Dispose() [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Concurrency\UserWorkItem.cs @ 43] 0000007B1A67B090 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67B0C0 00007ffbf66ffc7f System.Reactive.Sink1[[System.Int32, System.Private.CoreLib]].Dispose(Boolean) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Internal\Sink.cs @ 45]
0000007B1A67B0F0 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238]
0000007B1A67B120 00007ffbf6727512 System.Reactive.Linq.ObservableImpl.WithLatestFrom3+_[[System.Int32, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib]].Dispose(Boolean) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Linq\Observable\WithLatestFrom.cs @ 63] 0000007B1A67B150 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67B180 00007ffbf6696e12 System.Reactive.Linq.ObservableImpl.WithLatestFrom3+[[System.__Canon, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib]].Dispose(Boolean) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Linq\Observable\WithLatestFrom.cs @ 63]
0000007B1A67B1B0 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238]
0000007B1A67B1E0 00007ffbf6696e12 System.Reactive.Linq.ObservableImpl.WithLatestFrom3+_[[System.__Canon, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib]].Dispose(Boolean) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Linq\Observable\WithLatestFrom.cs @ 63] 0000007B1A67B210 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238] 0000007B1A67B240 00007ffbf6696e12 System.Reactive.Linq.ObservableImpl.WithLatestFrom3+[[System.__Canon, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib],[System.__Canon, System.Private.CoreLib]].Dispose(Boolean) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Linq\Observable\WithLatestFrom.cs @ 63]
0000007B1A67B270 00007ffbf59d6406 System.Reactive.Disposables.Disposable.TryDispose(System.IDisposable ByRef) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Disposables\Disposable.cs @ 238]
0000007B1A67B2A0 00007ffbf668af1f System.Reactive.Sink1[[System.__Canon, System.Private.CoreLib]].Dispose(Boolean) [d:\a\1\s\Rx.NET\Source\src\System.Reactive\Internal\Sink.cs @ 45] 0000007B1A67B2D0 00007ffbf6671057 OnRtls.Flotta.Audit.StreamingAuditService.Stop()

[akarnokd]

The recursive scheduling inside Generate will link up a lot of UserWorkItems via their _cancelRunDisposables.

https://github.com/dotnet/reactive/blob/master/Rx.NET/Source/src/System.Reactive/Linq/Observable/Generate.cs#L243

https://github.com/dotnet/reactive/blob/master/Rx.NET/Source/src/System.Reactive/Concurrency/UserWorkItem.cs#L29

I'll post a fix shortly.

[akarnokd]

Closing via #1067