There is a crash in iOS 13.1 and above. The crash occurred on the system library of the child thread. I don't know what happened? I tried to reproduce the crash, but it didn't work. Here is the stack:
#5 Thread
SIGSEGV
SEGV_ACCERR
libobjc.A.dylib objc_release + 16
1 libobjc.A.dylib AutoreleasePoolPage::releaseUntil(objc_object**) + 180
2 libobjc.A.dylib objc_autoreleasePoolPop + 224
3 libdispatch.dylib __dispatch_last_resort_autorelease_pool_pop + 40
4 libdispatch.dylib __dispatch_root_queue_drain + 1036
5 libdispatch.dylib __dispatch_worker_thread2 + 116
6 libsystem_pthread.dylib _pthread_wqthread + 212
#0 Thread
0 libsystem_kernel.dylib 0x00000001ab99f5f4 mach_msg_trap
1 libsystem_kernel.dylib 0x00000001ab99ea60 mach_msg
2 libdispatch.dylib 0x00000001ab86a4e0 __dispatch_mach_send_and_wait_for_reply
3 libdispatch.dylib 0x00000001ab86a89c _dispatch_mach_send_with_result_and_wait_for_reply$VARIANT$armv81
4 libxpc.dylib 0x00000001ab795544 xpc_connection_send_message_with_reply_sync
5 Foundation 0x00000001ac0b29e4 ___NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__
6 Foundation 0x00000001abe8c1d4 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:]
7 Foundation 0x00000001abeda65c -[NSXPCConnection _sendSelector:withProxy:arg1:arg2:arg3:arg4:]
8 Foundation 0x00000001ac0b95a4 __NSXPCDistantObjectSimpleMessageSend4
9 CoreTelephony 0x00000001b02c4300 -[CoreTelephonyClient(CarrierBundle) copyCarrierBundleValue:key:bundleType:error:]
10 CoreTelephony 0x00000001b02dc7b0 -[CTTelephonyNetworkInfo getCarrierName:forContext:withError:]
11 CoreTelephony 0x00000001b02dcea4 -[CTTelephonyNetworkInfo updateNetworkInfoAndShouldNotifyClient:forContext:]
12 CoreTelephony 0x00000001b02dc3a8 -[CTTelephonyNetworkInfo initWithClient:]
13 CoreTelephony 0x00000001b02dc00c -[CTTelephonyNetworkInfo init]
14 XXXXXX 0x00000001009c8370 -[HYNetService generalParameters] (HYNetService.m:81)
15 XXXXXX 0x0000000100dac39c -[HYNetCenter hy_configRequest:success:failure:] (HYNetCenter.m:57)
16 XXXXXX 0x0000000100dac218 -[HYNetCenter sendRequest:success:failure:] (HYNetCenter.m:0)
17 XXXXXX 0x00000001009c8a28 -[HYNetService sendRequest:completion:] (HYNetService.m:142)
18 XXXXXX 0x000000010098f414 +[HYTimetableAPI queryTimetableReommendDataWithSuccess:failure:] (HYTimetableAPI.m:75)
19 XXXXXX 0x0000000100a47c98 -[HYTimetableManager fetchTimetableRecommendDataWithSuccess:] (HYTimetableManager.m:135)
20 XXXXXX 0x0000000100a4741c -[HYTimetableManager init] (HYTimetableManager.m:43)
21 XXXXXX 0x0000000100a473b4 __34+[HYTimetableManager shareManager]_block_invoke (HYTimetableManager.m:33)
22 libdispatch.dylib 0x00000001ab896184 __dispatch_client_callout
23 libdispatch.dylib 0x00000001ab868f7c __dispatch_once_callout
24 XXXXXX 0x0000000100a4738c +[HYTimetableManager shareManager] (once.h:85)
25 XXXXXX 0x0000000100b876b0 -[HYBookshelfViewController viewWillAppear:] (HYBookshelfViewController.m:200)
26 UIKitCore 0x00000001af5cf20c -[UIViewController _setViewAppearState:isAnimating:]
27 UIKitCore 0x00000001af5cf8a0 -[UIViewController __viewWillAppear:]
28 UIKitCore 0x00000001af53c398 -[UINavigationController _startTransition:fromViewController:toViewController:]
29 UIKitCore 0x00000001af53cfa8 -[UINavigationController _startDeferredTransitionIfNeeded:]
30 UIKitCore 0x00000001af53e2ec -[UINavigationController __viewWillLayoutSubviews]
31 UIKitCore 0x00000001af522060 -[UILayoutContainerView layoutSubviews]
32 UIKitCore 0x00000001b0061270 -[UIView(CALayerDelegate) layoutSublayersOfLayer:]
33 QuartzCore 0x00000001b254d5f8 -[CALayer layoutSublayers]
34 QuartzCore 0x00000001b2551e28 CA::Layer::layout_if_needed(CA::Transaction*)
35 QuartzCore 0x00000001b255d894 CA::Layer::layout_and_display_if_needed(CA::Transaction*)
36 QuartzCore 0x00000001b24a69f0 CA::Context::commit_transaction(CA::Transaction*, double)
37 QuartzCore 0x00000001b24d0890 CA::Transaction::commit()
38 QuartzCore 0x00000001b24d1284 CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*)
39 CoreFoundation 0x00000001abb45c48 ___CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__
40 CoreFoundation 0x00000001abb40b34 ___CFRunLoopDoObservers
41 CoreFoundation 0x00000001abb41100 ___CFRunLoopRun
42 CoreFoundation 0x00000001abb408bc CFRunLoopRunSpecific
43 GraphicsServices 0x00000001b59ac328 GSEventRunModal
44 UIKitCore 0x00000001afbd66d4 UIApplicationMain
45 XXXXXX 0x0000000100b5f9e4 main (main.m:14)
46 libdyld.dylib 0x00000001ab9cb460 _start
As above, no information can be seen in the crash stack log, how to further analyze it？ Thank you for your help！