Crash in enumerateDisplaysWithBlock using Metal

Unity Engine
,
1

Hi,

We’ve got an update in review with Apple which has been rejected because of an uncaught exception on launch in the UnityGfxDeviceWorker thread. This is the exception:

*** Terminating app due to uncaught exception ‘NSGenericException’, reason: ‘*** Collection <NSConcreteMapTable: 0x13dd8b3c0> was mutated while being enumerated.’

The symbolicated callstack looks like this:

-[NSException name] (in CoreFoundation) + 0
-[NSConcreteMapTable countByEnumeratingWithState:objects:count:] (in Foundation) + 76
-[DisplayManager enumerateDisplaysWithBlock:] (in resynth) + 288
UnityStartFrameRendering (in resynth) + 52
GfxDeviceMetal::BeginFrame() (in resynth) (GfxDeviceMetal.mm:1606)
GfxDeviceWorker::RunCommand(ThreadedStreamBuffer&) (in resynth) (GfxDeviceWorker.cpp:1053)
GfxDeviceWorkerAutoreleasePoolProxy (in resynth) (GfxDeviceMetal.mm:1826)
GfxDeviceWorker::Run() (in resynth) (GfxDeviceWorker.cpp:328)
GfxDeviceWorker::RunGfxDeviceWorker(void*) (in resynth) (GfxDeviceWorker.cpp:316)
Thread::RunThreadWrapper(void*) (in resynth) (Thread.cpp:44)

We’re using Unity 5.4.3f1. The device the tester was using was running iOS 10.3.1 and it was an iPhone 6s Plus (hardware model iPhone8,2).

I haven’t been able to find anything in the issue tracker about this. Is this a known crash? Has it been fixed in another Unity version? I haven’t seen it happen before anywhere else on other iOS versions (I myself am on 10.3.2 at the moment and don’t have a 10.3.1 device to test with).

Thanks,
Sam

2

We have the same issue after we submit a test ipa to Testflight. We can run app on our device successfully, but Testflight Reviewer feedback this error. Our Unity version is 5.5.2f1.

Last Exception Backtrace:
0   CoreFoundation                    0x18a2211b8 0x18a0f1000 + 1245624
1   libobjc.A.dylib                   0x188c5855c 0x188c50000 + 34140
2   CoreFoundation                    0x18a220c00 0x18a0f1000 + 1244160
3   Foundation                        0x18ac3ba08 0x18ac2b000 + 68104
4   wzlz                              0x10002cb24 -[DisplayManager enumerateDisplaysWithBlock:] (DisplayManager.mm:322)
5   wzlz                              0x10002d654 UnityStartFrameRendering (DisplayManager.mm:504)
6   wzlz                              0x100df1180 GfxDeviceMetal::BeginFrame() (GfxDeviceMetal.mm:1855)
7   wzlz                              0x100a8ce94 GfxDeviceWorker::RunCommand(ThreadedStreamBuffer&) (GfxDeviceWorker.cpp:442)
8   wzlz                              0x100df2660 GfxDeviceWorkerAutoreleasePoolProxy (GfxDeviceMetal.mm:2510)
9   wzlz                              0x100a8f1b0 GfxDeviceWorker::Run() (GfxDeviceWorker.cpp:344)
10  wzlz                              0x100a895e0 GfxDeviceWorker::RunGfxDeviceWorker(void*) (GfxDeviceWorker.cpp:308)
11  wzlz                              0x100caf7f8 Thread::RunThreadWrapper(void*) (Thread.cpp:35)
12  libsystem_pthread.dylib           0x1892b5850 0x1892b2000 + 14416
13  libsystem_pthread.dylib           0x1892b5760 0x1892b2000 + 14176
14  libsystem_pthread.dylib           0x1892b2d94 0x1892b2000 + 3476

Mclockw

3

Also experiencing this issue in 2017.3f1 and is crashing on iPad Air 2. I was wondering if you managed to find a solution.

I did not recieve this error before and I do not know what caused it. I saw some similar posts about metal and multithreaded rendering so I am going to try to submit it for review with multithreaded rendering turned off.

Last Exception Backtrace:

0 CoreFoundation 0x180efb164 __exceptionPreprocess + 124 (NSException.m:166)
1 libobjc.A.dylib 0x180144528 objc_exception_throw + 56 (objc-exception.mm:521)
2 CoreFoundation 0x180efa7f0 __NSFastEnumerationMutationHandler + 128 (NSEnumerator.m:133)
3 Foundation 0x1817f9d84 -[NSConcreteMapTable countByEnumeratingWithState:objects:count:] + 76 (NSMapTable.m:1018)
4 --- 0x00000001009a1698 0x000000010098c000 + 87703
5 --- 0x000000010099b3a8 -[UnityAppController(Rendering) callbackPresent:] + 62375 (UnityAppController+Rendering.mm:114)
6 --- 0x000000010099b94c UnityPresentContextCallback + 63819 (UnityAppController+Rendering.mm:152)
7 --- 0x000000010138f658 GfxDeviceMetal::PresentFrame() + 10499671 (GfxDeviceMetal.mm:2754)
8 --- 0x000000010180d330 GfxDeviceWorker::RunCommand(ThreadedStreamBuffer&) + 15209263 (GfxDeviceWorker.cpp:1165)
9 --- 0x0000000101390ce8 GfxDeviceWorkerAutoreleasePoolProxy + 10505447 (GfxDeviceMetal.mm:3473)
10 --- 0x000000010180decc GfxDeviceWorker::RunExt(ThreadedStreamBuffer&) + 15212235 (GfxDeviceWorker.cpp:143)
11 --- 0x00000001018061a0 GfxDeviceWorker::RunGfxDeviceWorker(void*) + 15180191 (GfxDeviceWorker.cpp:310)
12 --- 0x000000010156381c Thread::RunThreadWrapper(void*) + 12417051 (Thread.cpp:36)
13 libsystem_pthread.dylib 0x180b242b4 _pthread_body + 308 (pthread.c:740)
14 libsystem_pthread.dylib 0x180b24180 _pthread_start + 312 (pthread.c:799)
15 libsystem_pthread.dylib 0x180b22b74 thread_start + 4
4

I ended up updating to 5.4.3p4. I forget whether that was for something else or for this bug specifically. I haven’t seen the bug since then, though. But you’re on a different version entirely so it sounds like the bug is still there… :confused:

-Sam

5

Hey Sam, thanks for your response. It could be a slightly different bug so if I find a solution I’ll let you know.

6

Hey Sam,

The app passed the review. Disabling multithreaded rendering did the trick.
Hope it will help someone.

Simon

7

This is still happening in 2017.4.0f1, yikes. Got my release delayed because of this.