Unity iOS 64 bit build crash at com.apple.IOAccelerator.BlockFences, Exception Subtype: KERN_INVALID

Unity Engine
,
1

I am using Unity 4.6.6f2 and made il2cpp build to support 64 bit requirement from apple. I am having strange random crash and in device crash logs, I see these crash reports. It is happening on multiple devices and all of them have this in common: Here’s the logs:

CodeType: ARM-64(Native)ParentProcess: launchd [1]

Date/Time:2015-06-1812:06:11.292+0400LaunchTime:2015-06-1811:50:59.940+0400
OS Version: iOS 8.1(12B410)ReportVersion:105

ExceptionType: EXC_BAD_ACCESS (SIGSEGV)ExceptionSubtype: KERN_INVALID_ADDRESS at 0x000000000000029cTriggeredbyThread:36

Thread36 name:smile:ispatch queue: com.apple.IOAccelerator.BlockFencesThread36Crashed:0 libobjc.A.dylib 0x0000000194b739f4 objc_disposeClassPair +1921 libobjc.A.dylib 0x0000000194b739bc objc_disposeClassPair +1362 libsystem_blocks.dylib 0x000000019520190c_Block_release+2523IOAccelerator0x000000018d68aca4 ioAccelCommandQueueBlockFenceCallback +604IOKit0x00000001851c58ccIODispatchCalloutFromCFMessage+3725IOKit0x00000001851c596c_IODispatchCalloutWithDispatch+366 libdispatch.dylib 0x00000001951b2a2c dispatch_mig_server +4327 libdispatch.dylib 0x00000001951ad368 _dispatch_client_callout +128 libdispatch.dylib 0x00000001951c20c4 _dispatch_source_latch_and_call +7889 libdispatch.dylib 0x00000001951af4d0 _dispatch_source_invoke +28410 libdispatch.dylib 0x00000001951b72a0 _dispatch_queue_drain +67211 libdispatch.dylib 0x00000001951b0470 _dispatch_queue_invoke +12812 libdispatch.dylib 0x00000001951b9220 _dispatch_root_queue_drain +66013 libdispatch.dylib 0x00000001951ba758 _dispatch_worker_thread3 +10414 libsystem_pthread.dylib 0x00000001953892e0 _pthread_wqthread +81215 libsystem_pthread.dylib 0x0000000195388fa4 start_wqthread +0
2

I have the same issue, Fabric (our bug tracker tool) is throwing thousand of that bug

Thread : Crashed: com.apple.IOAccelerator.BlockFences
0 libobjc.A.dylib 0x00000001983679f4 objc_disposeClassPair + 192
1 libsystem_blocks.dylib 0x0000000198a31910 _Block_release + 256
2 IOAccelerator 0x0000000190709edc ioAccelCommandQueueBlockFenceCallback + 64
3 IOKit 0x0000000187891470 IODispatchCalloutFromCFMessage + 376
4 IOKit 0x0000000187891510 _IODispatchCalloutWithDispatch + 40
5 libdispatch.dylib 0x00000001989df080 dispatch_mig_server + 436
6 libdispatch.dylib 0x00000001989d9954 _dispatch_client_callout + 16
7 libdispatch.dylib 0x00000001989f0010 _dispatch_source_latch_and_call + 2052
8 libdispatch.dylib 0x00000001989dbabc _dispatch_source_invoke + 288
9 libdispatch.dylib 0x00000001989e42d4 _dispatch_queue_drain + 2008
10 libdispatch.dylib 0x00000001989dca5c _dispatch_queue_invoke + 132
11 libdispatch.dylib 0x00000001989e6318 _dispatch_root_queue_drain + 720
12 libdispatch.dylib 0x00000001989e7c4c _dispatch_worker_thread3 + 108
13 libsystem_pthread.dylib 0x0000000198bb922c _pthread_wqthread + 816
14 libsystem_pthread.dylib 0x0000000198bb8ef0 start_wqthread + 4

Do you anything?

We built it with latest unity patch and with IL2CPP

Regards

3

Yep I see the same occasionally at seemingly random points even when Unity’s Accelerometer Frequency is set to disabled.

I’m using Unity 5.1.p3

4

I’m glad to see this thread since I’m having the same problem with 64bit IL2CPP builds on latest Unity 4.6.7p1
Any news on this bug?

Date/Time: 2015-07-21 12:08:48.029 +0300
Launch Time: 2015-07-21 12:04:56.725 +0300
OS Version: iOS 8.4 (12H143)
Report Version: 105

Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x00000000000007a0
Triggered by Thread: 30

Thread 30 name: Dispatch queue: com.apple.IOAccelerator.BlockFences
Thread 30 Crashed:
0 libobjc.A.dylib 0x00000001980379c0 objc_disposeClassPair + 140
1 libobjc.A.dylib 0x00000001980379bc objc_disposeClassPair + 136
2 racer 0x00000001016a6a74 0x10004c000 + 23439988
3 libsystem_blocks.dylib 0x000000019870190c _Block_release + 252
4 IOAccelerator 0x0000000190379ed8 ioAccelCommandQueueBlockFenceCallback + 60
5 IOKit 0x000000018750946c IODispatchCalloutFromCFMessage + 372
6 IOKit 0x000000018750950c _IODispatchCalloutWithDispatch + 36
7 libdispatch.dylib 0x00000001986af07c dispatch_mig_server + 432
8 libdispatch.dylib 0x00000001986a9950 _dispatch_client_callout + 12
9 libdispatch.dylib 0x00000001986c000c _dispatch_source_latch_and_call + 2048
10 libdispatch.dylib 0x00000001986abab8 _dispatch_source_invoke + 284
11 libdispatch.dylib 0x00000001986b42d0 _dispatch_queue_drain + 2004
12 libdispatch.dylib 0x00000001986aca58 _dispatch_queue_invoke + 128
13 libdispatch.dylib 0x00000001986b6314 _dispatch_root_queue_drain + 716
14 libdispatch.dylib 0x00000001986b7c48 _dispatch_worker_thread3 + 104
15 libsystem_pthread.dylib 0x0000000198889228 _pthread_wqthread + 812
16 libsystem_pthread.dylib 0x0000000198888eec start_wqthread + 0

5

I can’t find anything Unity specific in this trace…
Can you reproduce it locally?

6

@ImranZahid
@Ale_Moreno
@andsee
@rextr09
Do you use EveryPlay in your project ?

7

Same issue here. Unity game randomly crashes on iPhone 6 with iOS 8.4. I use (almost) latest Unity 5.1.2f1.

@ray-qzhang I have added Everyplay. Do you think it’s related?

8

@ray-qzhang , yes, I have Everyplay

9

I think @ray-qzhang has a point, because ever since I’ve disabled Everplay, I can’t reproduce the crash. Can anyone confirm that it’s related with Everyplay?

10

Still seeing this with Unity 4.6.7p3

Thread 36Queue : com.apple.IOAccelerator.BlockFences (serial)
#0 0x000000019639f9c8 in objc_disposeClassPair ()
#1 0x0000000196a2d910 in _Block_release ()
#2 0x000000018eeb5f1c in ioAccelCommandQueueBlockFenceCallback ()
#3 0x00000001869e98d0 in IODispatchCalloutFromCFMessage ()
#4 0x00000001869e9970 in _IODispatchCalloutWithDispatch ()
#5 0x0000000104bf68cc in dispatch_mig_server ()
#6 0x0000000104bf0df0 in _dispatch_client_callout ()
#7 0x0000000104c06cd4 in _dispatch_source_latch_and_call ()
#8 0x0000000104bf301c in _dispatch_source_invoke ()
#9 0x0000000104bfb5bc in _dispatch_queue_drain ()
#10 0x0000000104bf4120 in _dispatch_queue_invoke ()
#11 0x0000000104bfd75c in _dispatch_root_queue_drain ()
#12 0x0000000104bfef18 in _dispatch_worker_thread3 ()
#13 0x0000000196bb52e4 in _pthread_wqthread ()

11

The bug is still here. I’ve got a stack trace quite similar than the @bryan-files ’ one and I’ve Everyplay enabled, as @ray-qzhang pointed out. My project is of course in IL2CPP too.

Have any of you guys discovered anything, @rextr09 , @amjaliks ?

12

Still happening with Unity 4.6.8

13

@Manu_Sena I have just disabled the accelerometer, and crashes stopped. Fortunately, the accelerometer isn’t needed for my game, thus, it is solution for me.

14

The _Block_release related crash was an issue few Everyplay releases ago, but I haven’t seen it happening since, what is the build you’re using? The issue is Metal related and didn’t happen with GLES.

With Unity 5 and Everyplay plugin, there’s a known issue where upgrading the plugin might cause
GUID conflict on some situations, and the new files imported get named as duplicated (Everyplay.framework/Everyplay 2, etc)

15

It seems I have been celebrating too early.
I still get the same crash. It just happens not so often as previously.

I use Unity 5.1.3f1 and Everyplay 1990-1410.

16

I have same problem with Unity5.3.1p4 and Everyplay 2110-1530.
The crash is about per 1 hours.
Anyone?

17

I have seen this crash happen while attached to the Xcode debugger, With Unity 5.3.4f1, using Everyplay 2110-1530. The stack trace is similarly useless on its own, but I can see the assembly around it, starting in the function that calls objc_disposeClassPair. Of particular possible interest is the reference to EveryplayReleaseEntry. The EXC_BAD_ACCESS is in the call to objc_disposeClassPair at 0x10197a508

___entry_alloc_block_invoke_3:
0x10197a4ac <+0>: stp x20, x19, [sp, #-32]!
0x10197a4b0 <+4>: stp x29, x30, [sp, #16]
0x10197a4b4 <+8>: add x29, sp, #16 ; =16
0x10197a4b8 <+12>: mov x20, x1
0x10197a4bc <+16>: mov x19, x0
0x10197a4c0 <+20>: ldr x0, [x19, #40]
0x10197a4c4 <+24>: cbz x0, 0x10197a4cc ; <+32>
0x10197a4c8 <+28>: bl 0x101979f20 ; EveryplayReleaseEntry
0x10197a4cc <+32>: ldr x8, [x19, #48]
0x10197a4d0 <+36>: cbz x8, 0x10197a4e0 ; <+52>
0x10197a4d4 <+40>: ldr x1, [x19, #56]
0x10197a4d8 <+44>: mov x0, x20
0x10197a4dc <+48>: blr x8
0x10197a4e0 <+52>: adrp x0, 3083
0x10197a4e4 <+56>: add x0, x0, #120 ; =120
0x10197a4e8 <+60>: bl 0x101b60b00 ; symbol stub for: OSSpinLockLock
0x10197a4ec <+64>: ldr x8, [x19, #32]
0x10197a4f0 <+68>: ldr x8, [x8, #8]
0x10197a4f4 <+72>: ldr x0, [x8, #24]
0x10197a4f8 <+76>: cbz x0, 0x10197a500 ; <+84>
0x10197a4fc <+80>: bl 0x101b63548 ; symbol stub for: imp_removeBlock
0x10197a500 <+84>: ldr x0, [x19, #40]
0x10197a504 <+88>: cbz x0, 0x10197a50c ; <+96>
0x10197a508 <+92>: bl 0x101b63614 ; symbol stub for: objc_disposeClassPair
0x10197a50c <+96>: adrp x0, 3083
0x10197a510 <+100>: add x0, x0, #120 ; =120
0x10197a514 <+104>: ldp x29, x30, [sp, #16]
0x10197a518 <+108>: ldp x20, x19, [sp], #32
0x10197a51c <+112>: b 0x101b60b0c ; symbol stub for: OSSpinLockUnlock

18

We used everyplay too, although we had Metal disabled and GLES2 forced.

19

Hi, we just got this on Unity 5.3.4p6 on iPhone 6 iOS 9.3.1 when leaving the phone plugged into Xcode for some time idle.

Stack trace disassembly looks like it’s Everyplay related:

20

Also happening on iPhone 6+ and iPad Mini 4.

For those interested, our workaround is whitelisting devices without arm64 processors so any unreleased iOS devices won’t get this crash either.