Hi. After upgrading Kotlin from 1.8.10 to 1.8.20, I observed a critical issue for

DebugProbes.jobToString

, blocking all threads of my coroutines executor: • Threads are waiting for

coroutineStateLock

at kotlinx.coroutines.debug.internal.DebugProbesImpl.hierarchyToString(DebugProbesImpl.kt:111)
	at kotlinx.coroutines.debug.DebugProbes.jobToString(DebugProbes.kt:98)

• In that particular thread dump, the thread holding the lock was doing

at kotlin.coroutines.CombinedContext.get(CoroutineContextImpl.kt:120)
	at kotlinx.coroutines.JobKt__JobKt.getJob(Job.kt:630)
	at kotlinx.coroutines.JobKt.getJob(Unknown Source)
	at kotlinx.coroutines.debug.internal.DebugProbesImpl.hierarchyToString(DebugProbesImpl.kt:115)
	at kotlinx.coroutines.debug.DebugProbes.jobToString(DebugProbes.kt:98)

Has anyone else encountered something similar?

cc @Vsevolod Tolstopyatov [JB]

The 1.7.0-Beta and 1.7.0-RC are no longer prone to this issue, the coroutine debugger was made lock-less (i.e.

coroutineStateLock

is gone). Could you please tell if there is any progress in your application or if you are encountering a deadlock? It's likely that

hierarchyToString

doesn't scale well with the number of coroutines and, while doing its string concatenation, was preventing your system from doing any progress. If it is a deadlock though, it's a different issue that is worth investigating

Thank you! It looked like there was no deadlock, just extremely slow performance. I will try to apply 1.7.0-RC and get back to you if I still see the issue.