Bug 60104 - Problem with suspending thread that was attached/detached when unloading domain
Summary: Problem with suspending thread that was attached/detached when unloading domain
Alias: None
Product: Runtime
Classification: Mono
Component: GC ()
Version: 5.2 (2017-04)
Hardware: PC Windows
: Normal normal
Target Milestone: Future Cycle (TBD)
Assignee: Bugzilla
Depends on:
Reported: 2017-10-10 20:23 UTC by Michael Stoyke
Modified: 2017-11-08 21:21 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

Diff of the change I applied (597 bytes, patch)
2017-10-10 20:23 UTC, Michael Stoyke

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Description Michael Stoyke 2017-10-10 20:23:45 UTC
Created attachment 25257 [details]
Diff of the change I applied

We are using Mono as an embedded runtime and ran into this problem:
An app domain is created and some assemblies are loaded on the main thread. Then we create another thread and attach/detach the new thread to that app domain.

When unloading the app domain later on the main thread (after the other thread was detached and has ended) the thread state machine fails in mono_threads_transition_request_async_suspension() trying to suspend a thread that's in state STATE_ASYNC_SUSPEND_REQUESTED.

I've attached a potential fix to this ticket, but I wouldn't be surprised if this hackfix just hides the symptoms instead of solving the underlying problem.

We are using SGEN and have defined/enabled HAVE_CONC_GC_AS_DEFAULT
Comment 1 Ludovic Henry 2017-11-08 21:21:21 UTC

Unfortunately the diff you applied only hides the symptoms, and isn't a fix for the actual bug. Could you provide us with a repro case? Or some stacktraces?

Thank you,