Hi all. I've read all the posts related to CF_IS_OBJC, including this one, but since I don't have an Objective-C background and mostly work with Swift and SwiftUI, I'm struggling to fully understand the recommendations or how to address this issue. Could someone explain it to me in simple terms (like I'm 5) and provide a step-by-step guide on what to do? This crash has affected 66 devices over the past month.
Crashed: com.apple.main-thread
0 CoreFoundation 0xf878 CF_IS_OBJC + 24
1 CoreFoundation 0x17f58 CFArrayGetCount + 32
2 CoreGraphics 0x322a1c CGPDFTaggedNodeEnumerateChildren + 60
3 CoreGraphics 0x322880 CGPDFTaggedNodeGetBounds + 244
4 PDFKit 0x5524 -[UICGPDFNodeAccessibilityElement isAccessibilityElement]
5 UIAccessibility 0x48518 ___axuiElementForNotificationData_block_invoke + 28
6 UIAccessibility 0x35678 __94-[NSObject(AXPrivCategory) _accessibilityFindFirstAXDescendantPassingTest:byYieldingElements:]_block_invoke_2 + 36
7 UIAccessibility 0x3534c __96-[NSObject(AXPrivCategory) _accessibilityEnumerateAXDescendants:passingTest:byYieldingElements:]_block_invoke + 60
8 UIAccessibility 0x359d0 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke_2 + 60
9 UIAccessibility 0x1ec98 -[NSObject(AXPrivCategory) accessibilityEnumerateContainerElementsWithOptions:usingBlock:] + 548
10 UIAccessibility 0x35858 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke + 176
11 UIAccessibility 0x3539c __96-[NSObject(AXPrivCategory) _accessibilityEnumerateAXDescendants:passingTest:byYieldingElements:]_block_invoke + 140
12 UIAccessibility 0x359d0 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke_2 + 60
13 UIAccessibility 0x1ec98 -[NSObject(AXPrivCategory) accessibilityEnumerateContainerElementsWithOptions:usingBlock:] + 548
14 UIAccessibility 0x35858 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke + 176
15 UIAccessibility 0x3539c __96-[NSObject(AXPrivCategory) _accessibilityEnumerateAXDescendants:passingTest:byYieldingElements:]_block_invoke + 140
16 UIAccessibility 0x359d0 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke_2 + 60
17 UIAccessibility 0x1ec98 -[NSObject(AXPrivCategory) accessibilityEnumerateContainerElementsWithOptions:usingBlock:] + 548
18 UIAccessibility 0x35858 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke + 176
19 UIAccessibility 0x3539c __96-[NSObject(AXPrivCategory) _accessibilityEnumerateAXDescendants:passingTest:byYieldingElements:]_block_invoke + 140
20 UIAccessibility 0x359d0 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke_2 + 60
21 UIAccessibility 0x1ec98 -[NSObject(AXPrivCategory) accessibilityEnumerateContainerElementsWithOptions:usingBlock:] + 548
22 UIAccessibility 0x35858 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke + 176
23 UIAccessibility 0x3539c __96-[NSObject(AXPrivCategory) _accessibilityEnumerateAXDescendants:passingTest:byYieldingElements:]_block_invoke + 140
24 UIAccessibility 0x35918 __57-[NSObject(AXPrivCategory) _accessibilityFindDescendant:]_block_invoke + 368
25 UIAccessibility 0x3539c __96-[NSObject(AXPrivCategory) _accessibilityEnumerateAXDescendants:passingTest:byYieldingElements:]_block_invoke + 140
26 UIAccessibility 0x35294 -[NSObject _accessibilityEnumerateAXDescendants:passingTest:byYieldingElements:] + 244
27 UIAccessibility 0x355d0 -[NSObject _accessibilityFindFirstAXDescendantPassingTest:byYieldingElements:] + 272
28 UIAccessibility 0x35788 -[NSObject(AXPrivCategory) _accessibilityFindDescendant:] + 100
29 UIAccessibility 0x48280 _axuiElementForNotificationData + 276
30 UIAccessibility 0x347c _massageAssociatedElementBeforePost + 36
31 UIAccessibility 0x2648 _UIAXBroadcastMainThread + 292
32 libdispatch.dylib 0x213c _dispatch_call_block_and_release + 32
33 libdispatch.dylib 0x3dd4 _dispatch_client_callout + 20
34 libdispatch.dylib 0x125a4 _dispatch_main_queue_drain + 988
35 libdispatch.dylib 0x121b8 _dispatch_main_queue_callback_4CF + 44
36 CoreFoundation 0x56710 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 16
37 CoreFoundation 0x53914 __CFRunLoopRun + 1996
38 CoreFoundation 0x52cd8 CFRunLoopRunSpecific + 608
39 GraphicsServices 0x11a8 GSEventRunModal + 164
40 UIKitCore 0x40a90c -[UIApplication _run] + 888
41 UIKitCore 0x4be9d0 UIApplicationMain + 340
42 UIKitCore 0x638384 keypath_get_selector_hoverStyle + 11024
43 Wisconsin State Journal 0x3b4ae8 main + 4299246312 (AppDelegate.swift:4299246312)
44 ??? 0x1b7239e4c (Missing)
com.apple.uikit.eventfetch-thread
0 libsystem_kernel.dylib 0x1808 mach_msg2_trap + 8
1 libsystem_kernel.dylib 0x5008 mach_msg2_internal + 80
2 libsystem_kernel.dylib 0x4f20 mach_msg_overwrite + 436
3 libsystem_kernel.dylib 0x4d60 mach_msg + 24
4 CoreFoundation 0x53f5c __CFRunLoopServiceMachPort + 160
5 CoreFoundation 0x53600 __CFRunLoopRun + 1208
6 CoreFoundation 0x52cd8 CFRunLoopRunSpecific + 608
7 Foundation 0xc7e4c -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 212
8 Foundation 0xc7c9c -[NSRunLoop(NSRunLoop) runUntilDate:] + 64
9 UIKitCore 0x41e640 -[UIEventFetcher threadMain] + 420
10 Foundation 0xde718 __NSThread__start__ + 732
11 libsystem_pthread.dylib 0x606c _pthread_start + 136
12 libsystem_pthread.dylib 0x10d8 thread_start + 8
com.google.firebase.crashlytics.MachExceptionServer
0 Wisconsin State Journal 0x83b668 FIRCLSProcessRecordAllThreads + 392 (FIRCLSProcess.c:392)
1 Wisconsin State Journal 0x83ba48 FIRCLSProcessRecordAllThreads + 423 (FIRCLSProcess.c:423)
2 Wisconsin State Journal 0x849c5c FIRCLSHandler + 34 (FIRCLSHandler.m:34)
3 Wisconsin State Journal 0x84a460 FIRCLSMachExceptionServer + 521 (FIRCLSMachException.c:521)
4 libsystem_pthread.dylib 0x606c _pthread_start + 136
5 libsystem_pthread.dylib 0x10d8 thread_start + 8
Thread
0 libsystem_kernel.dylib 0x1808 mach_msg2_trap + 8
1 libsystem_kernel.dylib 0x5008 mach_msg2_internal + 80
...
As a first step, I suggest that you remove your third-party crash reporter. Debugging problems like this is hard, and third-party crash reporters make it harder. See Implementing Your Own Crash Reporter for more on that.
Once you have a ‘clean’ Apple crash report, please post an example here. It may offer some clues beyond the excerpt in your original post. See Posting a Crash Report for advice on how to post you crash report.
Problems like this are almost always the result of a memory management issue. And how you debug them depends on how reproducible they are:
This crash has affected 66 devices over the past month.
It sounds like you’re trying to debug this based on crash reports coming in from the field. That not easy. A good first step is to apply the standard memory debugging tools to see if you can make the problem more reproducible. If so, that’ll make debugging it more feasible.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"