Invalid memory pointer crash: cannot figure out cause

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Created Oct ’24

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Hi there! I'm one year into iOS development, and can usually figure out the cause of a crash. However, I've been bumping my head against this one for a while now.

Invalid memory pointer crash

According to this article, the crash (EXC_BAD_ACCESS) happens due to an invalid memory pointer. When I use the atos command to symbolicate the crash report, the line where the crash happens in my app (see line 39 in the full stack trace below) is simply the very first line in MyApp that extends App (annotated with @main) -- but there's no code on that line.

It seems like the error is happening somewhere with UIKit's UIViewController but I can't seem to figure it out.

Could be relevant code

I do have the following class in my app, which helps with hiding the tab bar I use when another view is opened. It might be relevant:

struct HideTabBar: UIViewControllerRepresentable {
    var callback: (UITabBar) -> Void
    private let proxyController = ViewController()
    
    func makeUIViewController(context: UIViewControllerRepresentableContext<HideTabBar>) ->
    UIViewController {
        proxyController.callback = callback
        return proxyController
    }
    
    func updateUIViewController(_ uiViewController: UIViewController, context: UIViewControllerRepresentableContext<HideTabBar>) {
    }
    
    typealias UIViewControllerType = UIViewController
    
    private class ViewController: UIViewController {
        var callback: (UITabBar) -> Void = { _ in }
        
        override func viewWillAppear(_ animated: Bool) {
            super.viewWillAppear(animated)
            if let tabBar = self.tabBarController {
                self.callback(tabBar.tabBar)
            }
        }
    }
}

Full stack trace:

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000010
Exception Codes: 0x0000000000000001, 0x0000000000000010
VM Region Info: 0x10 is not in any region.  Bytes before following region: 4363845616
      REGION TYPE                 START - END      [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      UNUSED SPACE AT START
--->  
Termination Reason: SIGNAL 11 Segmentation fault: 11
Terminating Process: exc handler [664]

Triggered by Thread:  0

Kernel Triage:
VM - (arg = 0x3) mach_vm_allocate_kernel failed within call to vm_map_enter


Thread 0 name:   Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libobjc.A.dylib               	       0x19205fc20 objc_msgSend + 32
1   UIKitCore                     	       0x19c697a68 -[UIViewController dealloc] + 860
2   UIKitCore                     	       0x19c863c80 -[UINavigationController dealloc] + 296
3   UIKitCore                     	       0x19c863b34 -[_UISplitViewControllerColumnContents .cxx_destruct] + 44
4   libobjc.A.dylib               	       0x192061acc object_cxxDestructFromClass(objc_object*, objc_class*) + 116
5   libobjc.A.dylib               	       0x192060f00 objc_destructInstance + 80
6   libobjc.A.dylib               	       0x192060ea4 _objc_rootDealloc + 80
7   CoreFoundation                	       0x19a0fc730 cow_cleanup + 164
8   CoreFoundation                	       0x19a0fec80 -[__NSDictionaryM dealloc] + 148
9   libobjc.A.dylib               	       0x192061acc object_cxxDestructFromClass(objc_object*, objc_class*) + 116
10  libobjc.A.dylib               	       0x192060f00 objc_destructInstance + 80
11  libobjc.A.dylib               	       0x192060ea4 _objc_rootDealloc + 80
12  UIKitCore                     	       0x19c8f4a54 -[UISplitViewControllerPanelImpl dealloc] + 100
13  libobjc.A.dylib               	       0x192061acc object_cxxDestructFromClass(objc_object*, objc_class*) + 116
14  libobjc.A.dylib               	       0x192060f00 objc_destructInstance + 80
15  libobjc.A.dylib               	       0x192060ea4 _objc_rootDealloc + 80
16  UIKitCore                     	       0x19c457730 -[UIResponder dealloc] + 124
17  UIKitCore                     	       0x19c697ba0 -[UIViewController dealloc] + 1172
18  libobjc.A.dylib               	       0x192060df4 AutoreleasePoolPage::releaseUntil(objc_object**) + 212
19  libobjc.A.dylib               	       0x192060c80 objc_autoreleasePoolPop + 260
20  UIKitCore                     	       0x19c4315ec -[_UIAfterCACommitBlock run] + 92
21  UIKitCore                     	       0x19c43149c -[_UIAfterCACommitQueue flush] + 164
22  UIKitCore                     	       0x19c4313b4 _runAfterCACommitDeferredBlocks + 496
23  UIKitCore                     	       0x19c430fec _cleanUpAfterCAFlushAndRunDeferredBlocks + 80
24  UIKitCore                     	       0x19c430efc _UIApplicationFlushCATransaction + 72
25  UIKitCore                     	       0x19c42e660 _UIUpdateSequenceRun + 84
26  UIKitCore                     	       0x19c42e2a4 schedulerStepScheduledMainSection + 172
27  UIKitCore                     	       0x19c42f148 runloopSourceCallback + 92
28  CoreFoundation                	       0x19a14b834 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
29  CoreFoundation                	       0x19a14b7c8 __CFRunLoopDoSource0 + 176
30  CoreFoundation                	       0x19a149298 __CFRunLoopDoSources0 + 244
31  CoreFoundation                	       0x19a148484 __CFRunLoopRun + 828
32  CoreFoundation                	       0x19a147cd8 CFRunLoopRunSpecific + 608
33  GraphicsServices              	       0x1deb951a8 GSEventRunModal + 164
34  UIKitCore                     	       0x19c781ae8 -[UIApplication _run] + 888
35  UIKitCore                     	       0x19c835d98 UIApplicationMain + 340
36  SwiftUI                       	       0x19e33c294 0x19df48000 + 4145812
37  SwiftUI                       	       0x19e2e8860 0x19df48000 + 3803232
38  SwiftUI                       	       0x19e2f461c 0x19df48000 + 3851804
39  MyApp                        	       0x1041f8690 0x1041b0000 + 296592
40  dyld                          	       0x1bd91f154 start + 2356

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