Mono .Net/NUnit projects, Mock of Interface with auto-property prevents debugging

Question

Using Mono 4.6.1 and Xamarin Studio [Community] running on MBP with OSX 10.11.6

I have a Solution, with two projects; one is the .NET project, the other NUnit test project for the first. When I mock an interface which uses auto properties (using Moq or NSubstitute) it causes mono to crash (SIGSTOP) during debugging.

public interface IExample
{
    string Name { get; }
}

[TestFixture]
public class Test
{
    [Test]
    public void TestCase()
    {
        var example = Substitute.For<IExample>();
        example.Name.Returns("Hat");
        Console.WriteLine(example.Name);
    }
}

If I put a breakpoint on the first line which creates the example substitute the system waits as expected. If I step over that line after about 1-2 seconds the system crashes (details below). NB: Running the test causes the test to pass because it doesn't take long enough for the background failure to trigger.

Application Output of failure:

Loaded assembly: /Applications/Xamarin Studio.app/Contents/Resources/lib/monodevelop/AddIns/MonoDevelop.UnitTesting/NUnit2/NUnitRunner.exe
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/System/4.0.0.0__b77a5c561934e089/System.dll
Loaded assembly: /Applications/Xamarin Studio.app/Contents/Resources/lib/monodevelop/AddIns/MonoDevelop.UnitTesting/NUnit2/nunit.core.interfaces.dll
Loaded assembly: /Applications/Xamarin Studio.app/Contents/Resources/lib/monodevelop/AddIns/MonoDevelop.UnitTesting/NUnit2/nunit.core.dll
Loaded assembly: /Applications/Xamarin Studio.app/Contents/Resources/lib/monodevelop/AddIns/MonoDevelop.UnitTesting/NUnit2/nunit.framework.dll
Loaded assembly: /Applications/Xamarin Studio.app/Contents/Resources/lib/monodevelop/AddIns/MonoDevelop.UnitTesting/NUnit2/nunit.util.dll
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/System.Runtime.Remoting/4.0.0.0__b77a5c561934e089/System.Runtime.Remoting.dll
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/System.Configuration/4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/System.Xml/4.0.0.0__b77a5c561934e089/System.Xml.dll
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/Mono.Security/4.0.0.0__0738eb9f132ed756/Mono.Security.dll
Thread started:  #2
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/System.Core/4.0.0.0__b77a5c561934e089/System.Core.dll
Thread started:  #3
Thread started: <Thread Pool> #4
Thread started: <Thread Pool> #5
Thread started: <Thread Pool> #6
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/System.Drawing/4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/nunit.util/2.4.8.0__96d09a1eb7f44a77/nunit.util.dll
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/nunit.core.interfaces/2.4.8.0__96d09a1eb7f44a77/nunit.core.interfaces.dll
Thread started:  #7
Loaded assembly: /Users/jeremy.connor/dev/MonoAPBug/MonoAPBug.Tests/bin/Debug/MonoAPBug.Tests.dll
Thread started: EventPumpThread #8
Thread started: TestRunnerThread #9
Resolved pending breakpoint at 'Test.cs:13,1' to void MonoAPBug.Tests.Test.TestCase () [0x00001].
Loaded assembly: /Users/jeremy.connor/dev/MonoAPBug/MonoAPBug.Tests/bin/Debug/MonoAPBug.exe
Loaded assembly: /Users/jeremy.connor/dev/MonoAPBug/MonoAPBug.Tests/bin/Debug/NSubstitute.dll
Loaded assembly: /Library/Frameworks/Mono.framework/Versions/4.6.1/lib/mono/gac/System.ServiceModel/4.0.0.0__b77a5c561934e089/System.ServiceModel.dll
Loaded assembly: DynamicProxyGenAssembly2
Loaded assembly: DynamicProxyGenAssembly2
mono(10800,0xb0319000) malloc: *** error for object 0x77c2a0: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
Stacktrace:


Native stacktrace:

    0   mono                                0x00171e46 mono_handle_native_sigsegv + 342
    1   mono                                0x001c5091 sigabrt_signal_handler + 145
    2   libsystem_platform.dylib            0x91d4579b _sigtramp + 43
    3   ???                                 0xffffffff 0x0 + 4294967295
    4   libsystem_c.dylib                   0x98fdcc38 abort + 156
    5   libsystem_malloc.dylib              0x96e51292 free + 433
    6   mono                                0x0032b266 mono_error_cleanup + 102
    7   mono                                0x001a7bda type_commands_internal + 2970
    8   mono                                0x0019b97d debugger_thread + 5261
    9   mono                                0x003340ca inner_start_thread + 474
    10  libsystem_pthread.dylib             0x96e06780 _pthread_body + 138
    11  libsystem_pthread.dylib             0x96e066f6 _pthread_body + 0
    12  libsystem_pthread.dylib             0x96e03f7a thread_start + 34

Debug info from gdb:

(lldb) command source -s 0 '/tmp/mono-gdb-commands.TQtGVg'
Executing commands in '/tmp/mono-gdb-commands.TQtGVg'.
(lldb) process attach --pid 10800
Process 10800 stopped
* thread #1: tid = 0x211a96, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_50b', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    frame #0: 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10
libsystem_kernel.dylib`__psynch_cvwait:
->  0x9386f3ea <+10>: jae    0x9386f3fa                ; <+26>
    0x9386f3ec <+12>: calll  0x9386f3f1                ; <+17>
    0x9386f3f1 <+17>: popl   %edx
    0x9386f3f2 <+18>: movl   0xf8cdc2f(%edx), %edx

Executable module set to "/Library/Frameworks/Mono.framework/Versions/4.6.1/bin/mono".
Architecture set to: i386-apple-macosx.
(lldb) thread list
Process 10800 stopped
* thread #1: tid = 0x211a96, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_50b', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
  thread #2: tid = 0x211a98, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread #3: tid = 0x211a9a, 0x938684d6 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread #4: tid = 0x211a9b, 0x9386fd5e libsystem_kernel.dylib`__workq_kernreturn + 10
  thread #5: tid = 0x211a9c, 0x938707fa libsystem_kernel.dylib`kevent_qos + 10, queue = 'com.apple.libdispatch-manager'
  thread #6: tid = 0x211a9d, 0x9386fcee libsystem_kernel.dylib`__wait4 + 10, name = 'Debugger agent'
  thread #7: tid = 0x211aa1, 0x9386fd5e libsystem_kernel.dylib`__workq_kernreturn + 10
  thread #8: tid = 0x211aa5, 0x9386fd5e libsystem_kernel.dylib`__workq_kernreturn + 10
  thread #9: tid = 0x211aa8, 0x9386e852 libsystem_kernel.dylib`__accept + 10, name = 'tid_2507'
  thread #10: tid = 0x211aa9, 0x9386f646 libsystem_kernel.dylib`__recvfrom + 10, name = 'tid_2b0b'
  thread #11: tid = 0x211aaa, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_330b'
  thread #12: tid = 0x211aab, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
  thread #13: tid = 0x211aac, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
  thread #14: tid = 0x211aad, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Timer-Scheduler'
  thread #15: tid = 0x211aaf, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'EventPumpThread'
  thread #16: tid = 0x211ab0, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'TestRunnerThread'
(lldb) thread backtrace all
* thread #1: tid = 0x211a96, 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_50b', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
  * frame #0: 0x9386f3ea libsystem_kernel.dylib`__psynch_cvwait + 10
    frame #1: 0x96e07538 libsystem_pthread.dylib`_pthread_cond_wait + 757
    frame #2: 0x96e09276 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
    frame #3: 0x0030a955 mono`mono_os_cond_timedwait [inlined] mono_os_cond_wait(cond=0x7a138238, mutex=0x7a13820c) + 12 at mono-os-mutex.h:107 [opt]
    frame #4: 0x0030a949 mono`mono_os_cond_timedwait(cond=<unavailable>, mutex=<unavailable>, timeout_ms=<unavailable>) + 185 at mono-os-mutex.h:122 [opt]
    frame #5: 0x0030a6cb mono`_wapi_handle_timedwait_signal_handle(handle=0x00001600, timeout=<unavailable>, alertable=<unavailable>, poll=<unavailable>, alerted=0xbff5e390) + 507 at handles.c:1555 [opt]
    frame #6: 0x0030a4c8 mono`_wapi_handle_timedwait_signal(timeout=4294967295, poll=0, alerted=0xbff5e23c) + 56 at handles.c:1476 [opt]
    frame #7: 0x0031eb5f mono`wapi_WaitForMultipleObjectsEx(numobjects=<unavailable>, handles=<unavailable>, waitall=<unavailable>, timeout=<unavailable>, alertable=<unavailable>) + 1775 at wait.c:620 [opt]
    frame #8: 0x002673d4 mono`mono_thread_manage [inlined] wait_for_tids_or_state_change(timeout=4294967295) + 82 at threads.c:3053 [opt]
    frame #9: 0x00267382 mono`mono_thread_manage + 322 at threads.c:3258 [opt]
    frame #10: 0x00138dc7 mono`mono_main(argc=<unavailable>, argv=<unavailable>) + 8855 at driver.g.c:2187 [opt]
    frame #11: 0x000a4141 mono`main [inlined] mono_main_with_options(argc=6, argc=6, argc=6, argv=0xbff5e944, argv=0xbff5e944, argv=0xbff5e944) + 33 at main.c:28 [opt]
    frame #12: 0x000a4120 mono`main(argc=6, argv=0xbff5e944) + 1184 at main.c:177 [opt]
    frame #13: 0x000a3c75 mono`start + 53

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.

Sorry for the offtopic, but SO doesn't provide direct messaging so I had no other way to write you. I read you use bit-shifting to protect strings in Android. Could you explain a little bit ? — JonZarate, Mar 10 '17 at 09:28
Apologies Jon, I did this years ago and can't remember the details. I think it boiled down to security from obscurity effectively changing the stored strings that are hardcoded into values that look like nonsense but are run through an algorithm to before use which converts them to sensible values. Ultimately it doesn't offer much security because if they're inspecting the contents of memory and you store the processed string in any variable it will be visible in it's cleaned form. Good luck. — Syntax, Mar 11 '17 at 13:26
That's what I thought. If someone decompiles the code can see what operations are performed. Have you found any other way to do it ? — JonZarate, Mar 11 '17 at 14:05
If I remember correct DexGuard (the paid version of ProGuard) had a mechanism for doing this - http://stackoverflow.com/questions/10220069/does-proguard-work-to-obfuscate-static-string-constants — Syntax, Mar 12 '17 at 11:28
That's where I saw you comment ! :D Any idea how DexGuard works? How do they secure the data? — JonZarate, Mar 12 '17 at 11:56
Best to check their website, if I did know it's long forgotten; good luck. — Syntax, Mar 13 '17 at 00:38

Mono .Net/NUnit projects, Mock of Interface with auto-property prevents debugging

0 Answers0