[net9] System.Private.CoreLib occurs InvalidOperationException and InvalidCastException

Open
#114,262 111 comments 14 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
15/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
csharp, ios
Domain
mobile-dev, operating-systems

Research direction

Start by investigating the Task.RunContinuations and ManualResetValueTaskSourceCore stack frames, then compare behavior between net8-ios and net9-ios on iOS 18. The issue has no reproduction steps, so establish a reliable reproduction before narrowing the regression; done means the crashes no longer occur and the regression is covered by a test or confirmed fix.

Written by the indexing model from the issue text.

Description

area-System.Threading regression-from-last-release runtime-mono
Description

reproduces absolutely randomly both in debug and in release mode, appeared after switching from net8-ios to net9-ios (It doesn't seem like it applies to iOS)

stacktrace of InvalidCastException:

System.InvalidCastException: Specified cast is not valid.
at System.Threading.Tasks.Task.RunContinuations(Object continuationObject)
at System.Threading.Tasks.Task.FinishContinuations()
at System.Threading.Tasks.Task.FinishStageThree()
at System.Threading.Tasks.Task.FinishStageTwo()
at System.Threading.Tasks.Task.FinishSlow(Boolean userDelegateExecute)
at System.Threading.Tasks.Task.Finish(Boolean userDelegateExecute)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
at System.Threading.Tasks.Task.ExecuteEntryUnsafe(Thread threadPoolThread)
at System.Threading.Tasks.Task.ExecuteFromThreadPool(Thread threadPoolThread)
at System.Threading.ThreadPoolWorkQueue.DispatchItemWithAutoreleasePool(Object workItem, Thread currentThread)
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()
at System.Threading.Thread.StartCallback()

stacktrace of InvalidOperationException (from Sentry):

System.InvalidOperationException: Arg_InvalidOperationException
?, in void ManualResetValueTaskSourceCore.SignalCompletion()
?, in void ManualResetValueTaskSourceCore.SetResult(long)
?, in void ThreadPoolValueTaskSource.ExecuteInternal()
?, in void ThreadPoolValueTaskSource.System.Threading.IThreadPoolWorkItem.Execute()
?, in void ThreadPoolWorkQueue.DispatchItemWithAutoreleasePool(object, Thread)
?, in bool ThreadPoolWorkQueue.Dispatch()
?, in void WorkerThread.WorkerThreadStart()

also screenshot from debug session (from AppDomain.CurrentDomain.UnhandledException):

Image

Reproduction Steps

have not steps

Expected behavior

no crashes

Actual behavior

crash occurs

Regression?

works in net8-ios

Known Workarounds

No response

Configuration

net9, ios 18

Other information

No response

Dominant language
C#
Stars
18.3k
Forks
5.6k
PR metrics pending

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from dotnet/runtime

All issues in dotnet/runtime

Similar issues

More C# issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.