Bug 13714 - SIGABRT when invoking an operation in the background
Summary: SIGABRT when invoking an operation in the background
Status: RESOLVED DUPLICATE of bug 13612
Alias: None
Product: iOS
Classification: Xamarin
Component: XI runtime ()
Version: 6.9.3.x
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2013-08-02 10:46 UTC by m
Modified: 2013-08-02 21:29 UTC (History)
2 users (show)

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

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Description m 2013-08-02 10:46:32 UTC
Maybe the summary is not descriptive enough, here are the details:

- I have a simple BooleanElement (MonoTouch Dialog framework)
- it's ValueChanged event calls a delegate:

booleanElement.ValueChanged+= (object sender, EventArgs 
				InvokeInBackground( () => Console.WriteLine ("Hello"));

In the iOS simulator, changing the slider (boolean value) three times will result in a SIGABRT.


=== Xamarin Studio ===

Version 4.0.10 (build 7)
Installation UUID: 76d28aff-1cda-4940-90df-b3b28c3cb454
	Mono 3.2.0 ((no/7c7fcc7)
	GTK 2.24.20
	GTK# (
	Package version: 302000000

=== Apple Developer Tools ===

Xcode 4.6.3 (2068)
Build 4H1503

=== Xamarin.iOS ===

Version: (Trial Edition)
Hash: c9f7659
Build date: 2013-18-07 21:36:03-0400

=== Xamarin.Android ===

Version: 4.8.0 (Starter Edition)
Android SDK: /Users/[hidden]/Library/Developer/Xamarin/android-sdk-mac_x86
	Supported Android versions:
		2.1   (API level 7)
		2.2   (API level 8)
		2.3   (API level 10)
		3.1   (API level 12)
		4.0   (API level 14)
		4.0.3 (API level 15)
Java SDK: /usr
java version "1.6.0_51"
Java(TM) SE Runtime Environment (build 1.6.0_51-b11-457-11M4509)
Java HotSpot(TM) 64-Bit Server VM (build 20.51-b01-457, mixed mode)

=== Xamarin.Mac ===

Xamarin.Mac: Not Installed

=== Build Information ===

Release ID: 400100007
Git revision: f324e2154ee86ae1b6b8483392eddbf418e6381b
Build date: 2013-07-20 06:23:58+0000
Xamarin addins: fe4f180e2386eafc00087ef68c3a580cff4a2592

=== Operating System ===

Mac OS X 10.8.4
Darwin para.lan 12.4.0 Darwin Kernel Version 12.4.0
    Wed May  1 17:57:12 PDT 2013
    root:xnu-2050.24.15~1/RELEASE_X86_64 x86_64

Starting iOS simulator 6.0
Launching application
Application launched. PID = 2532
Loaded assembly: /Developer/MonoTouch/usr/lib/mono/2.1/monotouch.dll [External]
Loaded assembly: /Developer/MonoTouch/usr/lib/mono/2.1/System.Core.dll [External]
Loaded assembly: /Developer/MonoTouch/usr/lib/mono/2.1/System.dll [External]
Thread started:  #2
Loaded assembly: /Users/[hidden]/bin/iPhoneSimulator/Debug/xclientiphone.exe
Loaded assembly: /Developer/MonoTouch/usr/lib/mono/2.1/MonoTouch.Dialog-1.dll [External]
Loaded assembly: /Developer/MonoTouch/usr/lib/mono/2.1/System.Xml.Linq.dll [External]
Loaded assembly: /Developer/MonoTouch/usr/lib/mono/2.1/System.Xml.dll [External]
Loaded assembly: /Developer/MonoTouch/usr/lib/mono/2.1/System.Json.dll [External]
Thread started:  #3
2013-08-02 16:40:15.807 [hidden][2532:617] Hello
Thread started:  #4
* Assertion at ../../../../../mono/mono/utils/mono-threads.c:155, condition `result' not met

Native stacktrace:

mono-rt: 	0   xclientiphone                       0x000b0b6a mono_handle_native_sigsegv + 266

mono-rt: 	1   xclientiphone                       0x000bd3cd sigabrt_signal_handler + 109

mono-rt: 	2   libsystem_c.dylib                   0x90c9b8cb _sigtramp + 43

mono-rt: 	3   ???                                 0xffffffff 0x0 + 4294967295

mono-rt: 	4   libsystem_sim_c.dylib               0x0422f57b abort + 140

mono-rt: 	5   [hidden]                       0x00206d8c monoeg_g_logv + 188

mono-rt: 	6   [hidden]                       0x00206dbb monoeg_assertion_message + 43

mono-rt: 	7   [hidden]                       0x001fc961 mono_thread_info_attach + 417

mono-rt: 	8   [hidden]                       0x001051e1 mono_gc_register_thread + 17

mono-rt: 	9   [hidden]                       0x001c133b mono_thread_attach_full + 91

mono-rt: 	10  [hidden]                       0x001c1679 mono_thread_attach + 25

mono-rt: 	11  [hidden]                       0x000dea86 mono_jit_thread_attach + 54

mono-rt: 	12  ???                                 0x0b4ef628 0x0 + 189724200

mono-rt: 	13  [hidden]                       0x0022bf59 monotouch_trampoline + 521

mono-rt: 	14  Foundation                          0x019f70d5 -[NSThread main] + 76

mono-rt: 	15  Foundation                          0x019f7034 __NSThread__main__ + 1304

mono-rt: 	16  libsystem_c.dylib                   0x90caf5b7 _pthread_start + 344

mono-rt: 	17  libsystem_c.dylib                   0x90c99d4e thread_start + 34

Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
Comment 1 m 2013-08-02 10:57:50 UTC
It seems to be the same symtom as described here:


For some reason, InvokeInBackground seems to result in the same thread registered twice...
Comment 2 Rolf Bjarne Kvinge [MSFT] 2013-08-02 21:29:13 UTC
InvokeInBackground is currently broken.

Please use ThreadPool.QueueUserWorkItem as an alternative (or create a new thread yourself if you really want a new thread).

*** This bug has been marked as a duplicate of bug 13612 ***