iPhone 10+ crash in deallocing an ARkit structure

Unity Engine
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1

The code is working on an iPhone7 device, but on iPhone10+, it’s crashing with SIGSEGV in “Thread 2” which isn’t started by my code:

Thread 2 name:
Thread 2 Crashed:
0   libobjc.A.dylib                   0x00000001ac268018 objc_release + 8 (NSObject.mm:1822)
1   CoreFoundation                    0x0000000197290c78 cow_cleanup + 144 (NSCollectionAux.h:48)
2   CoreFoundation                    0x000000019710d47c -[__NSDictionaryM dealloc] + 160 (NSCopyOnWrite.h:229)
3   CoreVideo                         0x000000019f889cc4 CVBuffer::finalize() + 56 (CVBufferInternal.cpp:69)
4   CoreVideo                         0x000000019f88b834 CVPixelBuffer::finalize() + 232 (CVPixelBufferInternal.cpp:309)
5   CoreFoundation                    0x00000001971ab104 _CFRelease + 248 (CFRuntime.c:2126)
6   ARKitCore                         0x00000001c2d052a0 -[ARImageData dealloc] + 60 (ARImageData.m:219)
7   ARKitCore                         0x00000001c2d97960 -[ARFrameContext .cxx_destruct] + 80 (ARFrameContext.m:41)
8   libobjc.A.dylib                   0x00000001ac248b10 object_cxxDestructFromClass(objc_object*, objc_class*) + 112 (objc-class.mm:455)
9   libobjc.A.dylib                   0x00000001ac25f840 objc_destructInstance + 80 (objc-class.mm:469)
10  libobjc.A.dylib                   0x00000001ac26680c _objc_rootDealloc + 80 (objc-runtime-new.mm:8131)
11  libobjc.A.dylib                   0x00000001ac248b10 object_cxxDestructFromClass(objc_object*, objc_class*) + 112 (objc-class.mm:455)
12  libobjc.A.dylib                   0x00000001ac25f840 objc_destructInstance + 80 (objc-class.mm:469)
13  libobjc.A.dylib                   0x00000001ac26680c _objc_rootDealloc + 80 (objc-runtime-new.mm:8131)
14  libobjc.A.dylib                   0x00000001ac248b10 object_cxxDestructFromClass(objc_object*, objc_class*) + 112 (objc-class.mm:455)
15  libobjc.A.dylib                   0x00000001ac25f840 objc_destructInstance + 80 (objc-class.mm:469)
16  libobjc.A.dylib                   0x00000001ac26680c _objc_rootDealloc + 80 (objc-runtime-new.mm:8131)
17  libobjc.A.dylib                   0x00000001ac248b10 object_cxxDestructFromClass(objc_object*, objc_class*) + 112 (objc-class.mm:455)
18  libobjc.A.dylib                   0x00000001ac25f840 objc_destructInstance + 80 (objc-class.mm:469)
19  libobjc.A.dylib                   0x00000001ac26680c _objc_rootDealloc + 80 (objc-runtime-new.mm:8131)
20  ARKitCore                         0x00000001c2df052c -[ARTechniqueParallelGatherContext captureGatheredData] + 1324 (ARTechniqueGatherContext.m:310)
21  ARKitCore                         0x00000001c2d76870 -[ARParentTechnique _submitResultsForTimestamp:context:] + 128 (ARParentTechnique.m:534)
22  libdispatch.dylib                 0x0000000196e21db0 _dispatch_client_callout + 20 (object.m:559)
23  libdispatch.dylib                 0x0000000196e2512c _dispatch_continuation_pop + 416 (inline_internal.h:2548)
24  libdispatch.dylib                 0x0000000196e36c08 _dispatch_source_invoke + 1260 (source.c:570)
25  libdispatch.dylib                 0x0000000196e28fd8 _dispatch_lane_serial_drain + 272 (inline_internal.h:2589)
26  libdispatch.dylib                 0x0000000196e29c90 _dispatch_lane_invoke + 460 (queue.c:3862)
27  libdispatch.dylib                 0x0000000196e2ae60 _dispatch_workloop_invoke + 1588 (inline_internal.h:2589)
28  libdispatch.dylib                 0x0000000196e33d78 _dispatch_workloop_worker_thread + 708 (queue.c:6601)
29  libsystem_pthread.dylib           0x00000001e2cdd814 _pthread_wqthread + 276 (pthread.c:2211)
30  libsystem_pthread.dylib           0x00000001e2ce476c start_wqthread + 8

It looks like a double free or a null pointer reference in ARFrameContext or thereabouts.

This is on Unity 2021.1.0f1, AR Kit and Foundation 4.1.5.

Is there a better forum I can submit a bug report?

2

Bounced this off the team. This does not seem like an ARF bug. This seems specific to ARKit. You can report issues to Bug Reporting - Apple Developer

3

I have the same problem my app crashes in thread 47

Thread 47 name:  Dispatch queue: com.apple.arkit.technique
Thread 47 Crashed:
0   libobjc.A.dylib                   0x00000001a1a78dc8 objc_release + 8
1   CoreFoundation                    0x000000018cf88f84 cow_cleanup + 144
2   CoreFoundation                    0x000000018cdffc04 -[__NSDictionaryM dealloc] + 148
3   CoreVideo                         0x00000001954d5cd8 CVBuffer::finalize+ 122072 () + 56
4   CoreVideo                         0x00000001954d7850 CVPixelBuffer::finalize+ 129104 () + 232
5   CoreFoundation                    0x000000018ce9faac _CFRelease + 248
6   ARKitCore                         0x00000001b8478804 -[ARImageData dealloc] + 60
7   ARKitCore                         0x00000001b850b90c -[ARFrameContext .cxx_destruct] + 80
8   libobjc.A.dylib                   0x00000001a1a58cd8 object_cxxDestructFromClass+ 23768 (objc_object*, objc_class*) + 112
9   libobjc.A.dylib                   0x00000001a1a70148 objc_destructInstance + 80
10  libobjc.A.dylib                   0x00000001a1a775c4 _objc_rootDealloc + 80
11  libobjc.A.dylib                   0x00000001a1a58cd8 object_cxxDestructFromClass+ 23768 (objc_object*, objc_class*) + 112
12  libobjc.A.dylib                   0x00000001a1a70148 objc_destructInstance + 80
13  libobjc.A.dylib                   0x00000001a1a775c4 _objc_rootDealloc + 80
14  libobjc.A.dylib                   0x00000001a1a58cd8 object_cxxDestructFromClass+ 23768 (objc_object*, objc_class*) + 112
15  libobjc.A.dylib                   0x00000001a1a70148 objc_destructInstance + 80
16  libobjc.A.dylib                   0x00000001a1a775c4 _objc_rootDealloc + 80
17  libobjc.A.dylib                   0x00000001a1a58cd8 object_cxxDestructFromClass+ 23768 (objc_object*, objc_class*) + 112
18  libobjc.A.dylib                   0x00000001a1a70148 objc_destructInstance + 80
19  libobjc.A.dylib                   0x00000001a1a775c4 _objc_rootDealloc + 80
20  ARKitCore                         0x00000001b8563c2c -[ARTechniqueParallelGatherContext captureGatheredData] + 1304
21  ARKitCore                         0x00000001b84ea308 -[ARParentTechnique _submitResultsForTimestamp:context:] + 128
22  libdispatch.dylib                 0x000000018cb1081c _dispatch_client_callout + 20
23  libdispatch.dylib                 0x000000018cb13cf4 _dispatch_continuation_pop + 448
24  libdispatch.dylib                 0x000000018cb264b8 _dispatch_source_invoke + 1284
25  libdispatch.dylib                 0x000000018cb17ecc _dispatch_lane_serial_drain + 308
26  libdispatch.dylib                 0x000000018cb18c34 _dispatch_lane_invoke + 456
27  libdispatch.dylib                 0x000000018cb19ee8 _dispatch_workloop_invoke + 1680
28  libdispatch.dylib                 0x000000018cb234bc _dispatch_workloop_worker_thread + 764
29  libsystem_pthread.dylib           0x00000001d7fc67a4 _pthread_wqthread + 276
30  libsystem_pthread.dylib           0x00000001d7fcd74c start_wqthread + 8

Here is crash log (sorry for pastern but this forum wouldn’t allow me to post it here) : iOS crash - Pastebin.com

What is causing it and is there any fix for it?: