Async Await crash on iOS14 with Xcode 13.2.1

jmuthialu · 2022-01-10T15:08:11.449Z

I am observing a crash on iOS14 device when I am using the new concurrency model in Xcode 13.2.1 which is backward compatible. The crash does not occur when I am running the code through Xcode but happens when I launch the app from home screen (without Xcode). I am providing a simple reproducible example which is crashing for me. I tried different workaround providing in this forum such as doable bitcode, linking lib swift_concurrency.tbd etc but no luck. I feel like I am missing something simple but don't know what it is. Any help please?

class ViewController: UIViewController {

    override func viewDidLoad()  {
        super.viewDidLoad()
        
        Task {
            await doAsyncTask()
            print("Async task completed")
        }
    }
    
    func doAsyncTask() async {
        do {
            try await Task.sleep(nanoseconds: 200000000)
        } catch {
            print("Error: \(error)")
        }
    }

}

Crash log

Incident Identifier: 0017AA48-0D67-4B07-9D0C-BF73FFFA7CA1
CrashReporter Key:   ca2738aeafe5d3959f146afb6c416107e7ba4679
Hardware Model:      iPhone12,1
Process:             Test1 [719]
Path:                /private/var/containers/Bundle/Application/D3C34DF1-FD68-4DCC-A174-E7F2A628C8BA/Test1.app/Test1
Identifier:          com.brightdrop.Test1
Version:             1 (1.0)
Code Type:           ARM-64 (Native)
Role:                Foreground
Parent Process:      launchd [1]
Coalition:           com.brightdrop.Test1 [654]


Date/Time:           2022-01-08 11:10:13.0089 -0500
Launch Time:         2022-01-08 11:10:12.9407 -0500
OS Version:          iPhone OS 14.8 (18H17)
Release Type:        User
Baseband Version:    2.06.00
Report Version:      104

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000
VM Region Info: 0 is not in any region.  Bytes before following region: 4304994304
      REGION TYPE                 START - END      [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      UNUSED SPACE AT START
--->  
      __TEXT                   100990000-1009a0000 [   64K] r-x/r-x SM=COW  ...st1.app/Test1

Termination Signal: Segmentation fault: 11
Termination Reason: Namespace SIGNAL, Code 0xb
Terminating Process: exc handler [719]
Triggered by Thread:  0

Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libswiftCore.dylib            	0x00000001af44e750 swift::ResolveAsSymbolicReference::operator()+ 3819344 (swift::Demangle::__runtime::SymbolicReferenceKind, swift::Demangle::__runtime::Directness, int, void const*) + 124
1   libswiftCore.dylib            	0x00000001af470018 swift::Demangle::__runtime::Demangler::demangleSymbolicReference+ 3956760 (unsigned char) + 212
2   libswiftCore.dylib            	0x00000001af470018 swift::Demangle::__runtime::Demangler::demangleSymbolicReference+ 3956760 (unsigned char) + 212
3   libswiftCore.dylib            	0x00000001af46cd04 swift::Demangle::__runtime::Demangler::demangleType(__swift::__runtime::llvm::StringRef, std::__1::function<swift::Demangle::__runtime::Node* + 3943684 (swift::Demangle::__runtime::SymbolicReferenceKind, swift::Demangle::__runtime::Directness, int, void const*)>) + 200
4   libswiftCore.dylib            	0x00000001af454660 swift_getTypeByMangledNameImpl(swift::MetadataRequest, __swift::__runtime::llvm::StringRef, void const* const*, std::__1::function<swift::TargetMetadata<swift::InProcess> const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* + 3843680 (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) + 496
5   libswiftCore.dylib            	0x00000001af451ab0 swift::swift_getTypeByMangledName(swift::MetadataRequest, __swift::__runtime::llvm::StringRef, void const* const*, std::__1::function<swift::TargetMetadata<swift::InProcess> const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* + 3832496 (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) + 604
6   libswiftCore.dylib            	0x00000001af451d08 swift_getTypeByMangledNameInContext + 152
7   Test1                         	0x0000000100997d5c 0x100990000 + 32092
8   Test1                         	0x0000000100998340 0x100990000 + 33600
9   UIKitCore                     	0x00000001ad80658c -[UIViewController _sendViewDidLoadWithAppearanceProxyObjectTaggingEnabled] + 108
10  UIKitCore                     	0x00000001ad80adb4 -[UIViewController loadViewIfRequired] + 956
11  UIKitCore                     	0x00000001ad80b178 -[UIViewController view] + 32
12  UIKitCore                     	0x00000001adf74c10 -[UIWindow addRootViewControllerViewIfPossible] + 180
13  UIKitCore                     	0x00000001adf743bc -[UIWindow _updateLayerOrderingAndSetLayerHidden:actionBlock:] + 236
14  UIKitCore                     	0x00000001adf752c0 -[UIWindow _setHidden:forced:] + 380
15  UIKitCore                     	0x00000001adf86800 -[UIWindow _mainQueue_makeKeyAndVisible] + 52
16  UIKitCore                     	0x00000001ae1b3b60 -[UIWindowScene _makeKeyAndVisibleIfNeeded] + 204
17  UIKitCore                     	0x00000001ad3b84ec +[UIScene _sceneForFBSScene:create:withSession:connectionOptions:] + 1632
18  UIKitCore                     	0x00000001adf3527c -[UIApplication _connectUISceneFromFBSScene:transitionContext:] + 1036
19  UIKitCore                     	0x00000001adf35610 -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] + 332
20  UIKitCore                     	0x00000001ada2b4e4 -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] + 388
21  FrontBoardServices            	0x00000001bab625d8 -[FBSScene _callOutQueue_agent_didCreateWithTransitionContext:completion:] + 440
22  FrontBoardServices            	0x00000001bab8dd44 __94-[FBSWorkspaceScenesClient createWithSceneID:groupID:parameters:transitionContext:completion:]_block_invoke.200 + 128
23  FrontBoardServices            	0x00000001bab716a4 -[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:] + 240
24  FrontBoardServices            	0x00000001bab8da0c __94-[FBSWorkspaceScenesClient createWithSceneID:groupID:parameters:transitionContext:completion:]_block_invoke + 372
25  libdispatch.dylib             	0x00000001ab12f81c _dispatch_client_callout + 20
26  libdispatch.dylib             	0x00000001ab13330c _dispatch_block_invoke_direct + 268
27  FrontBoardServices            	0x00000001babb5fa0 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 48
28  FrontBoardServices            	0x00000001babb5c30 -[FBSSerialQueue _targetQueue_performNextIfPossible] + 448
29  FrontBoardServices            	0x00000001babb6184 -[FBSSerialQueue _performNextFromRunLoopSource] + 32
30  CoreFoundation                	0x00000001ab4bd07c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
31  CoreFoundation                	0x00000001ab4bcf78 __CFRunLoopDoSource0 + 208
32  CoreFoundation                	0x00000001ab4bc2e8 __CFRunLoopDoSources0 + 376
33  CoreFoundation                	0x00000001ab4b625c __CFRunLoopRun + 820
34  CoreFoundation                	0x00000001ab4b59f4 CFRunLoopRunSpecific + 600
35  GraphicsServices              	0x00000001c2b86734 GSEventRunModal + 164
36  UIKitCore                     	0x00000001adf3375c -[UIApplication _run] + 1072
37  UIKitCore                     	0x00000001adf38fcc UIApplicationMain + 168
38  libswiftUIKit.dylib           	0x00000001bf30824c UIApplicationMain+ 94796 (_:_:_:_:) + 104
39  Test1                         	0x000000010099ab54 0x100990000 + 43860
40  Test1                         	0x000000010099aadc 0x100990000 + 43740
41  Test1                         	0x000000010099ac2c 0x100990000 + 44076
42  libdyld.dylib                 	0x00000001ab171cf8 start + 4

AlexisQapa · 2022-01-11T10:17:15.966Z

Does it crash in iOS 13/14 simulator ? Does it happen if you don't use concurrency but it's linked for ex a dependency define async interface but you don't call it ?

I don't have iOS 14 on hand and I'm afraid to push to production

jmuthialu · 2022-01-11T14:38:14.403Z

Does it crash in iOS 13/14 simulator ?
No (both M1 and Intel). It only crashes in device and that too when not run through Xcode. Strangely it works fine when I run the code using Xcode. What gives?

Does it happen if you don't use concurrency but it's linked for ex a dependency define async interface but you don't call it ?

No crashes if the code is not called but exists in the codebase.

jmuthialu · 2022-01-12T16:18:23.747Z

Has anyone able to run async await on iOS14/13 using Xcode 13.2.1 on a device? It can't be just me, right?

Douglas_Gregor · 2022-01-13T00:28:03.072Z

jmuthialu:

Has anyone able to run async await on iOS14/13 using Xcode 13.2.1 on a device? It can't be just me, right?

I have seen only one other report of this (via Feedback). In that report, the crash long implied that the concurrency back-deployment libraries either weren't in the installed app or weren't found at launch time. However, there wasn't enough there to reproduce the issue, and I haven't been able to reproduce this problem locally either. Various test projects that use async/await, as well as a fresh project with the view controller you provided, all work for me when launched on an iOS 14 device, whether from Xcode or from the home screen.

It might be something unexpected in your project or setup. Do you have a project you can share, here or via Feedback? Can you provide your build log so we can see whether, e.g., the appropriate back-deployment libraries are getting embedded into the app bundle?

Doug

tera · 2022-01-13T01:13:32.937Z

I can confirm the above report - the app above works when launched in Xcode, crashes immediately upon launch (after a very brief screen flash) when launched from the phone, both debug & release versions. Same crash log. iOS 14.5, iPhone XS+, Xcode 13.2.1.

Edit: the app works when launched via simulator's home screen.

willft · 2022-01-13T01:17:11.578Z

Not sure if this helps or not, but this sounds a lot like another crash I’ve seen with Xcode 13.2.1. Someone else posted with similar characteristics: https://developer.apple.com/forums/thread/697070

Backtrace suggests a crash inside the demangler
Crash only happens when compiled in release mode
Crash only occurs in iOS 14 (possibly earlier versions as well, but definitely not iOS 15)
Crash happens every time the relevant code is used (is not random)
Crash only happens when compiled with Xcode 13.2.1

Not exactly the same, as there was no concurrency near the call site for us - just SwiftUI with #available. We used the workaround in that dev forums post, so we’re no longer facing this issue. But I’m happy to supply crash logs or build logs via Feedback if it would help.

tera · 2022-01-13T01:29:47.455Z

The app was created in a brand new project just now. In my log the entries are not symbolicated (no idea why) but I see the same addresses for the first 6 lines and otherwise the crash log is the same as what's above.

Incident Identifier: 764D4576-DEEC-46EE-92A1-53F55C6E21AC
CrashReporter Key:   2c1bb366fc207ae9e3e606bfe58dedf8bbbc271e
Process:             CrashTest2 [26510]
Path:                /private/var/containers/Bundle/Application/28A4E1D6-5685-4718-8453-63D6DC29BCDB/CrashTest2.app/CrashTest2
Identifier:          test.CrashTest2
Version:             1 (1.0)
Code Type:           ARM-64 (Native)
Role:                Foreground
Parent Process:      launchd [1]
Coalition:           test.CrashTest2 [15650]


OS Version:          iPhone OS 14.5 (18E199)
Release Type:        User
Baseband Version:    3.03.05
Report Version:      104

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000
VM Region Info: 0 is not in any region.  Bytes before following region: 4303192064
      REGION TYPE                 START - END      [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      UNUSED SPACE AT START
--->  
      __TEXT                   1007d8000-1007e4000 [   48K] r-x/r-x SM=COW  ...pp/CrashTest2

Termination Signal: Segmentation fault: 11
Termination Reason: Namespace SIGNAL, Code 0xb
Terminating Process: exc handler [26510]
Triggered by Thread:  0

Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libswiftCore.dylib            	0x0000000188c98750 0x1888f4000 + 3819344
1   libswiftCore.dylib            	0x0000000188cba018 0x1888f4000 + 3956760
2   libswiftCore.dylib            	0x0000000188cba018 0x1888f4000 + 3956760
3   libswiftCore.dylib            	0x0000000188cb6d04 0x1888f4000 + 3943684
4   libswiftCore.dylib            	0x0000000188c9e660 0x1888f4000 + 3843680
5   libswiftCore.dylib            	0x0000000188c9bab0 0x1888f4000 + 3832496
6   libswiftCore.dylib            	0x0000000188c9bd08 0x1888f4000 + 3833096
7   CrashTest2                    	0x00000001007e017c 0x1007d8000 + 33148
8   CrashTest2                    	0x00000001007dff40 0x1007d8000 + 32576
9   UIKitCore                     	0x000000018705a958 0x186bbd000 + 4839768
10  UIKitCore                     	0x000000018705f180 0x186bbd000 + 4858240
11  UIKitCore                     	0x000000018705f544 0x186bbd000 + 4859204
12  UIKitCore                     	0x00000001877c8c98 0x186bbd000 + 12631192
13  UIKitCore                     	0x00000001877c8444 0x186bbd000 + 12629060
14  UIKitCore                     	0x00000001877c9348 0x186bbd000 + 12632904
15  UIKitCore                     	0x00000001877da888 0x186bbd000 + 12703880
16  UIKitCore                     	0x0000000187a07be8 0x186bbd000 + 14986216
17  UIKitCore                     	0x0000000186c0c8d8 0x186bbd000 + 325848
18  UIKitCore                     	0x0000000187789304 0x186bbd000 + 12370692
19  UIKitCore                     	0x0000000187789698 0x186bbd000 + 12371608
20  UIKitCore                     	0x000000018727f6ac 0x186bbd000 + 7087788
21  FrontBoardServices            	0x00000001943025d8 0x1942f8000 + 42456
22  FrontBoardServices            	0x000000019432dd44 0x1942f8000 + 220484
23  FrontBoardServices            	0x00000001943116a4 0x1942f8000 + 104100
24  FrontBoardServices            	0x000000019432da0c 0x1942f8000 + 219660
25  libdispatch.dylib             	0x00000001849937ec 0x18498f000 + 18412
26  libdispatch.dylib             	0x00000001849972dc 0x18498f000 + 33500
27  FrontBoardServices            	0x0000000194355fa0 0x1942f8000 + 384928
28  FrontBoardServices            	0x0000000194355c30 0x1942f8000 + 384048
29  FrontBoardServices            	0x0000000194356184 0x1942f8000 + 385412
30  CoreFoundation                	0x0000000184d20848 0x184c7d000 + 669768
31  CoreFoundation                	0x0000000184d20744 0x184c7d000 + 669508
32  CoreFoundation                	0x0000000184d1fab4 0x184c7d000 + 666292
33  CoreFoundation                	0x0000000184d19a28 0x184c7d000 + 641576
34  CoreFoundation                	0x0000000184d191c0 0x184c7d000 + 639424
35  GraphicsServices              	0x000000019c301734 0x19c2fe000 + 14132
36  UIKitCore                     	0x00000001877877e4 0x186bbd000 + 12363748
37  UIKitCore                     	0x000000018778d054 0x186bbd000 + 12386388
38  libswiftUIKit.dylib           	0x0000000198a9f24c 0x198a88000 + 94796
39  CrashTest2                    	0x00000001007e0110 0x1007d8000 + 33040
40  libdyld.dylib                 	0x00000001849d5cf8 0x1849d4000 + 7416

Thread 1:
0   libsystem_pthread.dylib       	0x00000001d07c9744 0x1d07bf000 + 42820

Thread 2:
0   libsystem_pthread.dylib       	0x00000001d07c9744 0x1d07bf000 + 42820

Thread 3:
0   libsystem_pthread.dylib       	0x00000001d07c9744 0x1d07bf000 + 42820

Thread 4:
0   libsystem_pthread.dylib       	0x00000001d07c9744 0x1d07bf000 + 42820

Thread 5:
0   libsystem_pthread.dylib       	0x00000001d07c9744 0x1d07bf000 + 42820

Thread 6 name:  com.apple.uikit.eventfetch-thread
Thread 6:
0   libsystem_kernel.dylib        	0x00000001b2d7a4fc 0x1b2d76000 + 17660
1   libsystem_kernel.dylib        	0x00000001b2d79884 0x1b2d76000 + 14468
2   CoreFoundation                	0x0000000184d1fd10 0x184c7d000 + 666896
3   CoreFoundation                	0x0000000184d19bb0 0x184c7d000 + 641968
4   CoreFoundation                	0x0000000184d191c0 0x184c7d000 + 639424
5   Foundation                    	0x0000000185ff9fac 0x185ff2000 + 32684
6   Foundation                    	0x0000000185ff9e78 0x185ff2000 + 32376
7   UIKitCore                     	0x000000018783c38c 0x186bbd000 + 13104012
8   Foundation                    	0x000000018616b2fc 0x185ff2000 + 1544956
9   libsystem_pthread.dylib       	0x00000001d07c0c00 0x1d07bf000 + 7168
10  libsystem_pthread.dylib       	0x00000001d07c9758 0x1d07bf000 + 42840

Thread 7:
0   libsystem_pthread.dylib       	0x00000001d07c9744 0x1d07bf000 + 42820

Thread 8:
0   libsystem_pthread.dylib       	0x00000001d07c9744 0x1d07bf000 + 42820

Thread 0 crashed with ARM Thread State (64-bit):
    x0: 0x000000016f625200   x1: 0x0000000000000000   x2: 0x0000000000000000   x3: 0x000000000000043d
    x4: 0x00000001007e3bd3   x5: 0x000000016f625aa0   x6: 0x00000002838c2220   x7: 0x0000000000000000
    x8: 0x0000000000000001   x9: 0x0000000188c9ea6c  x10: 0x0000000000000001  x11: 0x0000000000000007
   x12: 0x0000000000000001  x13: 0x0000000000000000  x14: 0xfffffffffffffff4  x15: 0x0000000187dca3b1
   x16: 0x0000000000000000  x17: 0x0000000188cb8198  x18: 0x0000000000000000  x19: 0x000000016f625200
   x20: 0x000000016f625030  x21: 0x0000000000000000  x22: 0x000000016f624ec0  x23: 0x000000016f625ac0
   x24: 0x000000016f625aa0  x25: 0x00000001007e3bd2  x26: 0x0000000000000007  x27: 0x0000000000000000
   x28: 0x0000000000000000   fp: 0x000000016f624e60   lr: 0xc56fdd8188cba018
    sp: 0x000000016f624e40   pc: 0x0000000188c98750 cpsr: 0x60000000
   esr: 0x92000006 (Data Abort) byte read Translation fault

Binary Images:
0x1007d8000 - 0x1007e3fff CrashTest2 arm64  <ffe87ecb67c333aeaf1e9a1e87764297> /var/containers/Bundle/Application/28A4E1D6-5685-4718-8453-63D6DC29BCDB/CrashTest2.app/CrashTest2
0x100810000 - 0x100883fff dyld arm64e  <ca553810334f351692ecaedeaa5c0426> /usr/lib/dyld
0x1009c4000 - 0x1009cffff libobjc-trampolines.dylib arm64e  <f23e71e84220389a901aa5f2398905ee> /usr/lib/libobjc-trampolines.dylib
0x18498f000 - 0x1849d3fff libdispatch.dylib arm64e  <ffc93e7e836032a09eb5fe3761b8c90a> /usr/lib/system/libdispatch.dylib
0x1849d4000 - 0x184a10fff libdyld.dylib arm64e  <b08ab7c264e839379487c33d0175fd34> /usr/lib/system/libdyld.dylib
0x184a11000 - 0x184c7cfff libicucore.A.dylib arm64e  <ab7fcb3c67263f4697a573d41da6f4ea> /usr/lib/libicucore.A.dylib
0x184c7d000 - 0x18503cfff CoreFoundation arm64e  <58500388bf36397c84cf17315a3445b6> /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation
0x18503d000 - 0x1851ebfff CoreServices arm64e  <6c07f046e45a3faf97885725a53f1ee7> /System/Library/Frameworks/CoreServices.framework/CoreServices
0x185234000 - 0x1852b0fff SystemConfiguration arm64e  <73f1b810e3ac3491a337b14b62ce0bd1> /System/Library/Frameworks/SystemConfiguration.framework/SystemConfiguration
0x1852b1000 - 0x1853a6fff CoreTelephony arm64e  <07e708ee6f8d3cb9a37383f72b4c3eea> /System/Library/Frameworks/CoreTelephony.framework/CoreTelephony
0x1853a7000 - 0x185838fff CFNetwork arm64e  <048134a8c3cb3b41bc1df2f16e824512> /System/Library/Frameworks/CFNetwork.framework/CFNetwork
0x185839000 - 0x185f7cfff libnetwork.dylib arm64e  <816831deee0435f8a76cf90daa7b1ae6> /usr/lib/libnetwork.dylib
0x185f7d000 - 0x185ff1fff Accounts arm64e  <206a05d79eab36ca96deb5c27cf4768f> 
.....

EOF

jmuthialu · 2022-01-13T02:39:00.116Z

@Douglas_Gregor

Thanks for testing the ViewController I provided. I am bit surprised that it did not crash for you on an iOS 14 device without Xcode, but it could potentially indicate that I could be missing something.

Please see below the project link which is crashing for me. This also contains build log where it suggests that --back-deploy-swift-concurrency is set and libswift_Concurrency.dylib seems to be deployed.

GitHub

GitHub - jmuthialu/AsycnCrashTest

Contribute to jmuthialu/AsycnCrashTest development by creating an account on GitHub.

zavsby · 2022-01-13T08:38:38.264Z

Same reproduces for me (Xcode 13.2.1). Any build from xcode (both debug and release) are crashing on launch from home screen on iOS 13-14 on any concurrency code. When launched in debug from xcode or build as archive and submitted to TF - works well.
Easily reproduced on simple project with just one async/await call.

jmuthialu · 2022-01-13T15:34:42.547Z

Yep. You summed it up nicely @zavsby . I have not tested through Test Flight nor through adhoc builds and it is good to know it does not crash through Test Flight. I will try an adhoc build and see what happens.

I am curious to know why would it crash when launching release builds from Home Screen but not via TestFlight? Is optimizer playing a role and if so how?

zavsby · 2022-01-13T16:57:03.387Z

After our short investigation I see that the difference between archived and build via debug is libswift_concurrency added into bundle. I've tried to replace libswift_concurrency in build folder (when build via xcode debug) with the library generated when archiving project (they have different size 1.1 MB vs 11MB) and rebuild app via xcode (it won't replace it in build folder until you make clean). In this case when I launch from home screen - it works.
So it's definitely linking or library issue.

tera · 2022-01-13T17:50:39.809Z

zavsby:

I've tried to replace libswift_concurrency in build folder (when build via xcode debug) with the library generated when archiving project (they have different size 1.1 MB vs 11MB) and rebuild app via xcode (it won't replace it in build folder until you make clean). In this case when I launch from home screen - it works.

Nice hack. I confirm in this case it works.

tera · 2022-01-13T17:58:23.016Z

Anyone here has iOS 13 device to try this?

Douglas_Gregor · 2022-01-13T17:59:42.558Z

jmuthialu:

Please see below the project link which is crashing for me. This also contains build log where it suggests that --back-deploy-swift-concurrency is set and libswift_Concurrency.dylib seems to be deployed.

Fascinating. The build log indicates that libswift_Concurrency.dylib is correctly being copied into the app in the right place. I see the same thing locally. For me, this app builds and works properly when launching it from the home screen on iOS 14.

Thanks for hanging with me as we try to figure out what's going on here... there are two next steps I can think of.

The first is if you can grab the built .app that's crashing for you. The log tells us that the library is being copied in, but it's possible that the executable isn't linking it correctly. By looking at the built app (specifically, the Test1 executable), we can see whether it's linking the concurrency library properly.

The second is that I wanted to ask more about your workflow. You build locally, and you run it from the home screen, but what's the step in between that transfers the built app to the device?

zavsby:

After our short investigation I see that the difference between archived and build via debug is libswift_concurrency added into bundle.

Do you have build logs and a built app for this? Build-via-debug should copy libswift_Concurrency.dylib into the app, always. If it isn't, that's a sure sign of a bug---either somewhere in the compiler (i.e., we're not referencing the library), linker (it's dropping the reference), or build system the copy of the library.

zavsby:

I've tried to replace libswift_concurrency in build folder (when build via xcode debug) with the library generated when archiving project (they have different size 1.1 MB vs 11MB)

The size difference is because the original libswift_Concurrency.dylib contains bitcode (that's the ~11MB). When you build without archiving, the bitcode is stripped out of the library so the library is ~1MB.

Doug

tera · 2022-01-13T18:15:02.414Z

Douglas_Gregor:

You build locally, and you run it from the home screen, but what's the step in between that transfers the built app to the device?

Can't say for @jmuthialu, I do it this way: build and run app from Xcode (release or debug mode, doesn't matter) - it works. Stop the app (e.g. via Xcode, doesn't matter), launch the app from iPhone's home screen - doesn't work.

Douglas_Gregor:

The size difference is because the original libswift_Concurrency.dylib contains bitcode (that's the ~11MB). When you build without archiving, the bitcode is stripped out of the library so the library is ~1MB.

If I disable bitcode, and then try @zavsby 's trick of substituting the library taken from archive - the library is small indeed, and the trick doesn't work.

zavsby · 2022-01-13T18:23:49.531Z

True. If I disable bitcode and make an archive - it also starts crashing from Home screen. It seems it somehow related to bitcode. I will attach all you’ve asked soon.

zavsby · 2022-01-13T18:25:55.246Z

About iOS 13, I’ve tried on it and everything the same as for iOS 14. Btw it does not crash on simulator.
Also maybe important we are using M1 macs to compile.

tera · 2022-01-13T18:29:56.176Z

zavsby:

About iOS 13, I’ve tried on it and everything the same as for iOS 14.

Noted

zavsby:

Btw it does not crash on simulator.

Same here

zavsby:

Also maybe important we are using M1 macs to compile.

No, i am on Intel.

Tried this: modified the app slightly to call async stuff after 10 second delay - the app launches correctly and then crashes after 10 seconds.

tera · 2022-01-13T18:51:13.045Z

I managed to get this crash in Xcode:

Screenshot 2022-01-13 at 6.49.59Pm2752×1628 765 KB