Some crashes on Unity 4.6.4 for iOS - 64bits

Hi there

We have an app, built for 64bits with IL2CPP for iOS with Fabric (formerly called Crashlytics) and we are receiving some crashed on AppWillTerminate with all version of Unity (we started working on it on 4.6.3). It's quite strange, because to it seems to happen once the app is killed from background by OS due to memory pressure

Do you know anything about this? It's quite weird

Regards

Here is the raw of the crash

Thread : Crashed: com.apple.main-thread
0 libsystem_kernel.dylib 0x3853ddf0 __pthread_kill + 8
1 libsystem_pthread.dylib 0x385bccc7 pthread_kill + 62
2 libsystem_c.dylib 0x384d9909 abort + 76
3 Scooby 0x01865270 GC_stop_world (darwin_stop_world.c:569)
4 Scooby 0x018644f4 GC_stopped_mark (alloc.c:610)
5 Scooby 0x0186407c GC_try_to_collect_inner (alloc.c:460)
6 Scooby 0x01860a6c GC_collect_or_expand (alloc.c:1260)
7 Scooby 0x01860d64 GC_allocobj (alloc.c:1349)
8 Scooby 0x0185f544 GC_generic_malloc_inner (malloc.c:133)
9 Scooby 0x01860e34 GC_generic_malloc (malloc.c:182)
10 Scooby 0x01861870 GC_malloc (misc.c:381)
11 Scooby 0x018b7b10 il2cpp::vm::Object::Clone(Il2CppObject*) (Object.cpp:52)
12 Scooby 0x00b104f8 MulticastDelegate_RemoveImpl_m1569 (GeneratedVirtualInvokers.h:20)
13 Scooby 0x00b11ef0 Delegate_Remove_m1466 (Bulk_mscorlib_0.cpp:61557)
14 Scooby 0x001e6168 EventManager_remove_OnDarkBackgroundOut_m3980 (il2cpp-codegen.h:331)
15 Scooby 0x002fedd0 TutorialEvent_OnDestroy_m4589 (il2cpp-codegen.h:331)
16 Scooby 0x00ce2ce0 RuntimeInvoker_Void_t54(MethodInfo*, void*, void**) (GeneratedInvokers.cpp:12)
17 Scooby 0x018bd048 il2cpp::vm::Runtime::Invoke(MethodInfo*, void*, void**, Il2CppObject**) (Runtime.cpp:307)
18 Scooby 0x0130a344 ScriptingInvocation::Invoke(ScriptingException**, bool) (ScriptingInvocation.cpp:128)
19 Scooby 0x0130a8dc ScriptingInvocationNoArgs::InvokeChecked() (ScriptingInvocationNoArgs.cpp:83)
20 Scooby 0x012fe21c MonoBehaviour::CallMethodInactive(ScriptingMethodIl2Cpp) (MonoBehaviour.cpp:370)
21 Scooby 0x01114664 Unity::GameObject::WillDestroyGameObject() (stl_iterator.h:752)
22 Scooby 0x012a8264 PreDestroyRecursive(Unity::GameObject&, unsigned long*) (stl_vector.h:400)
23 Scooby 0x012a84bc DestroyGameObjectHierarchy(Unity::GameObject&) (GameObject.h:424)
24 Scooby 0x012a8904 DestroyObjectHighLevel(Object*, bool) (GameObjectUtility.cpp:1447)
25 Scooby 0x012c7bd8 CleanupAllObjects(bool) (BaseObject.h:845)
26 Scooby 0x012c8430 CleanupEngine() (SaveAndLoadHelper.cpp:450)
27 Scooby 0x012b004c PlayerCleanup(bool, bool) (Player.cpp:1162)
28 Scooby 0x01005378 UnityCleanup (LibEntryPoint.mm:235)
29 UIKit 0x2d1d18b1 -[UIApplication _terminateWithStatus:] + 192
30 UIKit 0x2d3b8349 -[UIApplication _handleApplicationDectivationWithScene:shouldForceExit:transitionContext:completion:] + 2416
31 UIKit 0x2d3b38e7 -[UIApplication workspaceShouldExit:] + 166
32 FrontBoardServices 0x305c2ec9 __31-[FBSSerialQueue performAsync:]_block_invoke_2 + 16
33 CoreFoundation 0x29ac1fd5 __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
34 CoreFoundation 0x29ac1299 __CFRunLoopDoBlocks + 216
35 CoreFoundation 0x29abfa37 __CFRunLoopRun + 790
36 CoreFoundation 0x29a0c201 CFRunLoopRunSpecific + 476
37 CoreFoundation 0x29a0c013 CFRunLoopRunInMode + 106
38 GraphicsServices 0x311e8201 GSEventRunModal + 136
39 UIKit 0x2d1b0a59 UIApplicationMain + 1440
40 Scooby 0x000b09e4 main (main.mm:45)

 

Thanks Josh for the time. Yes, it is reproducible if in debug, you start opening others app until WatchDog tries to close yours.

This crash is from our crash tracker tool, crashlytics.

In method "TutorialEvent_OnDestroy" we only desubscribe from an event, but this couldn't be the error, this line is executed everytime we change scene.

very strange

 

Is there an update for this issue? We are having the exact same problem.

 

Well have you tried the lasted version of Unity to see if the problem still exists?
4.6.6 even patch releases, considering that each new release has had a tone of fixes for iOS 64bit

 

Looking at my crashes in XCode from my live app, I'm seeing a VERY similar crash stack in my app as well. I've been unable to repro it locally so far. Like the OP, this looks to be triggered by desubscribing to an event, but in my case, I'm desubscribing in OnDisable (not OnDestroy like the OP).

My app was built with Unity 4.6.6p1

 

Just to let you know, our latest game update built on 4.6.6p4 still have this issue. But no STR on our side either.

 

I have soft launched a game a few days ago, with about 100 users right now. We got 9 crashes, apparently from the same device / user, all apparently starting after the game is killed because of memory pressure.

8 of the crashes have a very similar stack, of an exception triggered during GameObject destroy that calls our Log Handler which then tries to allocate memory (and then fail) while reporting the issue to our server.

And here's the remaining one again at cleanup time (OnDestroy -> save -> Json Serialization -> allocation -> crash )

App is IL2CPP built 4.6.5f1 based. Device exhibiting issue is running IOS 8.3.

 

@JoshPeterson the affected device is an ipad Air (A1474). It has double the amount of RAM as my test device (ipad2) and I have never managed to crash the app on the ipad2 in normal use.

I will try further with swapping the app out etc.

In all cases, it looks like I should be able to take some preventive measures by reducing the amount of work that happens during this shutdown phase. The OnApplicationQuit() seems to be sent too late (http://docs.unity3d.com/Manual/ExecutionOrder.html). Is there a way for me to programatically check that Unity is shutting down ? Maybe Application.isPlaying is false ?

 

The first thing I noticed was the stack
1. UnityCleanup()
2. triggers object Destroy ?
3. something goes wrong, Exception triggered
4. Log Handler kicks in (the one from the Perf module)
5. because of its implementation, it allocates objects before starting the coroutine
6. crash (probably because memory constrained so allocation fail ?!)

I have been trying to create a reproducible case in the past few hours. I managed to create some oddities but no crash. Without knowing more of what's happening inside the hood, I cannot turn thee symptoms as bugs to report yet.

I have 2 issues:
* I didnt' manage to get the UnityCleanup() call to be triggered upon memory pressure. At least I don't know where to place my breakpoints in order to see it happening. If I put a breakpoint on a OnDestroy() somewhere, then if the app if killed while in the background or foreground because of memory pressure, calls to OnDestroy() don't seem to happen. So my point #2 is maybe incorrectly understood:

What does the above stack mean ? Does this mean that the Destroy() method of a GameObject threw an exception ? Or is the exception coming internally form Unity ?

* Any tip on how to trigger a UnityCleanup() call ?

 

@JoshPeterson

I'll investigate some more, although travelling all day tomorrow, then partially in holidays.

Some thoughts:
* I will try calling UnityCleanup
* I will try killing the app manually
* I don't know who the user is, nor can I send a special build right now. The LogCallbackImplementation is yours (the Perf service one).

I will probably try modifying the UnityAppController.mm so that I can track the applicationWillTerminate() callback. That way I shut down the LogCallbackImplementation when this Unity is shutting down.

 

Seemingly same issue here. On 4.6.9f1, Xcode 7, IL2PCC, happening on wide range of iOS devices, iPhone / iPad, 32 / 64 bit and OS versions 8.4-9.1.

Will investigate further soon but here's trace:


1 libsystem_kernel.dylib __pthread_kill + 8
2 libsystem_pthread.dylib pthread_kill + 108
3 libsystem_c.dylib abort + 136
4 [APPNAME] GC_stop_world + 172
5 [APPNAME] GC_stopped_mark + 80
6 [APPNAME] GC_try_to_collect_inner + 292
7 [APPNAME] GC_collect_or_expand + 216
8 [APPNAME] GC_allocobj + 228
9 [APPNAME] GC_generic_malloc_inner + 496
10 [APPNAME] GC_generic_malloc + 112
11 [APPNAME] GC_malloc + 232
12 [APPNAME] il2cpp::vm::Object::Clone(Il2CppObject*) + 40
13 [APPNAME] MulticastDelegate_RemoveImpl_m29023 (GeneratedVirtualInvokers.h:33)
14 [APPNAME] UIAnchor_OnDestroy_m3555 (Bulk_Assembly-CSharp_2.cpp:1994)
15 [APPNAME] RuntimeInvoker_Void_t2283(MethodInfo const*, void*, void**) (Il2CppInvokerTable.cpp:828)
16 [APPNAME] il2cpp::vm::Runtime::Invoke(MethodInfo const*, void*, void**, Il2CppObject**) + 64
17 [APPNAME] ScriptingInvocation::Invoke(ScriptingException**, bool) + 52
18 [APPNAME] ScriptingInvocationNoArgs::InvokeChecked() + 56
19 [APPNAME] MonoBehaviour::CallMethodInactive(ScriptingMethodIl2Cpp) + 72
20 [APPNAME] Unity::GameObject::WillDestroyGameObject() + 80
21 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 112
22 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 244
23 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 244
24 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 244
25 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 244
26 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 244
27 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 244
28 [APPNAME] PreDestroyRecursive(Unity::GameObject&, unsigned long*) + 244
29 [APPNAME] DestroyGameObjectHierarchy(Unity::GameObject&) + 40
30 [APPNAME] DestroyObjectHighLevel(Object*, bool) + 896
31 [APPNAME] CleanupAllObjects(bool) + 276
32 [APPNAME] CleanupEngine() + 40
33 [APPNAME] PlayerCleanup(bool, bool) + 60
34 [APPNAME] UnityCleanup + 16
35 UIKit -[UIApplication _terminateWithStatus:] + 276
36 UIKit __102-[UIApplication _handleApplicationDeactivationWithScene:shouldForceExit:transitionContext:completion:]_block_invoke1976 + 312
37 UIKit _runAfterCACommitDeferredBlocks + 288
38 UIKit _cleanUpAfterCAFlushAndRunDeferredBlocks + 88
39 UIKit _afterCACommitHandler + 92
40 CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 28
41 CoreFoundation __CFRunLoopDoObservers + 368
42 CoreFoundation __CFRunLoopRun + 924
43 CoreFoundation CFRunLoopRunSpecific + 380
44 GraphicsServices GSEventRunModal + 176
45 UIKit UIApplicationMain + 200
46 [APPNAME] main (main.mm:37)
47 libdyld.dylib start + 0

 

I think this related too

http://answers.unity3d.com/questions/961173/some-crashes-on-unity-464-for-ios.html

 

Some recent discoveries on this and I hope to get a repro to you soon if I can find time @JoshPeterson

I'm fairly certain we don't actually receive crash logs for the crashes caused by 'memory' pressure, so I think there are two distinct problems. My trace above might not be related to OP's issue.

1 - Memory Pressure Crash
In Xcode we get a message like "terminated due to memory pressure". We use HockeyApp to collect reports and having done a unique build purely to try and isolate this problem it seems that nothing is logged, having made the app crash 3 times.

An easy way to trigger this issue for us is to close all the open apps, open our game, minimise it, then open all the apps on our home screen. At some point during opening the apps the crash occurs, but we need to open enough apps to cause the crash. Interestingly, if we maximise the game every few app opens, and then keep opening apps, the crash doesn't seem to occur (only tried that once, perhaps the app gets re-prioritised for available memory when it's maximised).

2 - Crash on User Quit
My trace above actually relates to a crash that's logged every time the app is quit intentionally by the user. It would seem not detrimental to user experience but crash stats are tracked and taken into account by Apple so definitely not good for us - as you can imagine we have a crazy lot of these crashes logged per app version.

Based on stats from live builds this crash is across all iOS hardware types and OS versions.

 

I have similar issue, when user quit my app in ios device
On 4.6.9f1, Xcode 7, IL2PCC, happening on wide range of iOS devices, iPhone / iPad, 32 / 64 bit
Here is the raw of the crash

Code Type: ARM-64
Parent Process: ??? [1]

Date/Time: 2015-11-24T08:57:25Z
OS Version: iPhone OS 9.1 (13B143)
Report Version: 104

Exception Type: SIGSEGV
Exception Codes: SEGV_ACCERR at 0x0
Crashed Thread: 0

Thread 0 Crashed:
0 myapp 0x0000000101453194 MemoryManager:eallocate(void*, MemLabelId) (MemoryManager.cpp:1080)
1 myapp 0x000000010150a384 Renderer::ClearPropertyBlock() (dynamic_array.h:322)
2 myapp 0x00000001016cd104 Animator::ClearRelatedPropertyBlocks() (Animator.cpp:1057)
3 myapp 0x00000001016cd0bc Animator:eactivate(Unity:eactivateOperation) (Animator.cpp:148)
4 myapp 0x000000010145ce5c Unity::GameObject::ActivateAwakeRecursivelyInternal(Unity:eactivateOperation, AwakeFromLoadQueue&) (GameObject.cpp:227)
5 myapp 0x000000010145cdbc Unity::GameObject::ActivateAwakeRecursivelyInternal(Unity:eactivateOperation, AwakeFromLoadQueue&) (GameObject.cpp:209)
6 myapp 0x000000010145cdbc Unity::GameObject::ActivateAwakeRecursivelyInternal(Unity:eactivateOperation, AwakeFromLoadQueue&) (GameObject.cpp:209)
7 myapp 0x000000010145cf10 Unity::GameObject::ActivateAwakeRecursively(Unity:eactivateOperation) (GameObject.cpp:241)
8 myapp 0x0000000101591a18 DestroyGameObjectHierarchy(Unity::GameObject&) (GameObjectUtility.cpp:1283)
9 myapp 0x0000000101591df4 DestroyObjectHighLevel(Object*, bool) (GameObjectUtility.cpp:1447)
10 myapp 0x00000001015a8534 CleanupAllObjects(bool) (SaveAndLoadHelper.cpp:298)
11 myapp 0x00000001015a8ab0 CleanupEngine() (SaveAndLoadHelper.cpp:450)
12 myapp 0x0000000101597430 PlayerCleanup(bool, bool) (Player.cpp:1162)
13 myapp 0x000000010138b574 UnityCleanup (LibEntryPoint.mm:238)
14 UIKit 0x000000018a2cbae0 -[UIApplication _terminateWithStatus:] + 276
15 UIKit 0x000000018a4e93f8 __102-[UIApplication _handleApplicationDeactivationWithScene:shouldForceExit:transitionContext:completion:]_block_invoke1974 + 312
16 UIKit 0x000000018a4ec56c _runAfterCACommitDeferredBlocks + 288
17 UIKit 0x000000018a4f94bc _cleanUpAfterCAFlushAndRunDeferredBlocks + 88
18 UIKit 0x000000018a22d984 _afterCACommitHandler + 92
19 CoreFoundation 0x0000000184c5fbd0 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 28
20 CoreFoundation 0x0000000184c5d974 __CFRunLoopDoObservers + 368
21 CoreFoundation 0x0000000184c5dda4 __CFRunLoopRun + 924
22 CoreFoundation 0x0000000184b8cca0 CFRunLoopRunSpecific + 380
23 GraphicsServices 0x000000018fdc8088 GSEventRunModal + 176
24 UIKit 0x000000018a2a4ffc UIApplicationMain + 200
25 myapp 0x00000001000852dc main (main.mm:37)
26 libdyld.dylib 0x0000000199fba8b8 start + 0

 

@JoshPeterson
Thanks for reply, I have resolved the problem, but I don't know why! here's my method:
class Someclass : MonoBehaviour{
void OnApplicationQuit(){
Application.LoadLevel("EmptyScene");// unload the scene that cause the crash.
Resources.UnloadUnusedAssets();
}
}

 

@little_bunny @JoshPeterson the above didn't work for me but I just did some digging and found the problem cause for us. It was to do with NGUI which we still use.

I've posted to NGUI forums as it seems more relevant there and included cause and our solution:
http://www.tasharen.com/forum/index.php?topic=13178.msg59344

@Ale Moreno looking at your original trace it seems you have the same crash cause but triggered from a different place. In the middle lines you can see also you are attempting to de-reference what is probably an empty delegate in your EventManager class. Looks like a few months back so I expect you've solved but for anyone else getting the whole GC_World crash hope it's useful.