iOS 11 EXC_BAD_ACCESS KERN_INVALID_ADDRESS on dealloc - ios

Question

Can't replicate a crash on iOS 11 devices when deallocating the DetailViewController.
The app has a DetailViewController which inherits from the BaseViewController. DetailViewController has a DetailViewModel property.
DetailViewController, BaseViewController and DetailViewModel are all written in Objective-C. I upgraded the Swift version to Swift 4 and added a Swift Extension to DetailViewModel.
#objc extension DetailViewModel {
func foo() {
let conclusionBlock: (() -> Void) = { [weak self] in
guard let strongSelf = self else { return }
strongSelf.viewController.reloadData()
}
let viewModel = OtherViewModel(conclusionBlock: conclusionBlock)
let otherViewController = OtherViewController.make(viewModel: viewModel)
let nav = UINavigationController(rootViewController: otherViewController)
nav.modalPresentationStyle = .fullScreen
viewController.present(nav, animated: true, completion: nil)
}
}
Looking at the logs, func foo() in the DetailViewModel swift extension is not called and it's still crashing on dealloc.
Has anyone got ideas as to what's the issue or how to fix it?
Thank you
stack trace:
Crashed: com.apple.main-thread
0 libobjc.A.dylib 0x18589d7f4 objc_object::release() + 16
1 CoreFoundation 0x1862f3108 cow_cleanup + 112
2 CoreFoundation 0x18623a51c -[__NSArrayM dealloc] + 68
3 libobjc.A.dylib 0x18587eef4 object_cxxDestructFromClass(objc_object*, objc_class*) + 148
4 libobjc.A.dylib 0x18588c638 objc_destructInstance + 88
5 libobjc.A.dylib 0x18588c690 object_dispose + 16
6 AppName 0x100c7dbec -[DetailViewModel .cxx_destruct] (DetailViewModel.m:43)
7 libobjc.A.dylib 0x18587eef4 object_cxxDestructFromClass(objc_object*, objc_class*) + 148
8 libobjc.A.dylib 0x18588c638 objc_destructInstance + 88
9 libobjc.A.dylib 0x18588c690 object_dispose + 16
10 AppName 0x100cbe358 -[DetailViewController .cxx_destruct] (DetailViewController.m:103)
11 libobjc.A.dylib 0x18587eef4 object_cxxDestructFromClass(objc_object*, objc_class*) + 148
12 libobjc.A.dylib 0x18588c638 objc_destructInstance + 88
13 libobjc.A.dylib 0x18588c690 object_dispose + 16
14 UIKit 0x18fb338f4 -[UIResponder dealloc] + 156
15 UIKit 0x18f8e9e7c -[UIViewController dealloc] + 1776
16 AppName 0x100c9b66c -[BaseViewController dealloc] (BaseViewController.m:56)
17 AppName 0x100cb6570 -[DetailViewController dealloc] (DetailViewController.m:261)
18 UIKit 0x18f9d3ec4 __destroy_helper_block_.150 + 80
19 libsystem_blocks.dylib 0x185d91a60 _Block_release + 160
20 UIKit 0x18fa5f5bc -[UIViewAnimationBlockDelegate .cxx_destruct] + 72
21 libobjc.A.dylib 0x18587eef4 object_cxxDestructFromClass(objc_object*, objc_class*) + 148
22 libobjc.A.dylib 0x18588c638 objc_destructInstance + 88
23 libobjc.A.dylib 0x18588c690 object_dispose + 16
24 CoreFoundation 0x18623d998 -[__NSDictionaryI dealloc] + 136
25 libobjc.A.dylib 0x18589e138 (anonymous namespace)::AutoreleasePoolPage::pop(void*) + 836
26 CoreFoundation 0x186232050 _CFAutoreleasePoolPop + 28
27 CoreFoundation 0x186311b04 __CFRunLoopRun + 2020
28 CoreFoundation 0x1862322d8 CFRunLoopRunSpecific + 436
29 GraphicsServices 0x1880c3f84 GSEventRunModal + 100
30 UIKit 0x18f7df880 UIApplicationMain + 208
31 AppName 0x100d59540 main (main.m:10)
32 libdyld.dylib 0x185d5656c start + 4

Answer 1

To help with replicating the issue, try turning on Address Sanitizer in Xcode 9.

Answer 2

You have an object stored in an array that is over-released when the object is destroyed and is releasing its array.
You can first activate zombie objects (clic your target near the PLAY button, choose scheme/Run/Diagnostics/Zombie objects). in this mode, objects are not really released, so you can query the object causing the crash to see what is its type and begin to track it.