[ios] [5.3.1] rare crash when going from background to foreground

[Overtorment]

Description

I once experienced a crash when my app was in the background for a while, and I opened so it tried to go to foreground.
I immediately looked up our crash report on bugsnag:

NSInvalidArgumentException
TcpSockets.m:166
*** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[0]
Oct 5th, 2021, 11:44:31 UTC

STACKTRACE

CrashReporter Key:  57d0876ed81edcd073b616649639e4eae2160bcf
Hardware Model:     iPhone12,1
Process:            BlueWallet
Identifier:         io.bluewallet.bluewallet
Version:            6.2.9
Role:               Foreground
OS Version:         iOS 15.0


NSInvalidArgumentException: *** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[0]

0  CoreFoundation    ___exceptionPreprocess
1  libobjc.A.dylib   _objc_exception_throw
2  CoreFoundation    __CFThrowFormattedException
3  CoreFoundation    -[__NSPlaceholderDictionary initWithObjects:forKeys:count:].cold.5
4  CoreFoundation    -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]
5  CoreFoundation    +[NSDictionary dictionaryWithObjects:forKeys:count:]
6  BlueWallet        -[TcpSockets onConnect:] (TcpSockets.m:166:24)
7  BlueWallet        -[TcpSocketClient socketDidSecure:] (TcpSocketClient.m:294:5)
8  BlueWallet        __42-[GCDAsyncSocket ssl_continueSSLHandshake]_block_invoke (GCDAsyncSocket.m:7344:5)
9  libdispatch.dylib __dispatch_call_block_and_release
10 libdispatch.dylib __dispatch_client_callout
11 libdispatch.dylib __dispatch_main_queue_callback_4CF
12 CoreFoundation    ___CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
13 CoreFoundation    ___CFRunLoopRun
14 CoreFoundation    _CFRunLoopRunSpecific
15 GraphicsServices  _GSEventRunModal
16 UIKitCore         -[UIApplication _run]
17 UIKitCore         _UIApplicationMain
18 BlueWallet        main (main.m:14:12)

THREADS

Thread 0
0  CoreFoundation    ___exceptionPreprocess
1  libobjc.A.dylib   _objc_exception_throw
2  CoreFoundation    __CFThrowFormattedException
3  CoreFoundation    -[__NSPlaceholderDictionary initWithObjects:forKeys:count:].cold.5
4  CoreFoundation    -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]
5  CoreFoundation    +[NSDictionary dictionaryWithObjects:forKeys:count:]
6  BlueWallet        -[TcpSockets onConnect:] (TcpSockets.m:166:24)
7  BlueWallet        -[TcpSocketClient socketDidSecure:] (TcpSocketClient.m:294:5)
8  BlueWallet        __42-[GCDAsyncSocket ssl_continueSSLHandshake]_block_invoke (GCDAsyncSocket.m:7344:5)
9  libdispatch.dylib __dispatch_call_block_and_release
10 libdispatch.dylib __dispatch_client_callout
11 libdispatch.dylib __dispatch_main_queue_callback_4CF
12 CoreFoundation    ___CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
13 CoreFoundation    ___CFRunLoopRun
14 CoreFoundation    _CFRunLoopRunSpecific
15 GraphicsServices  _GSEventRunModal
16 UIKitCore         -[UIApplication _run]
17 UIKitCore         _UIApplicationMain
18 BlueWallet        main (main.m:14:12)

Thread 1
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 CoreFoundation          ___CFRunLoopServiceMachPort
3 CoreFoundation          ___CFRunLoopRun
4 CoreFoundation          _CFRunLoopRunSpecific
5 Foundation              -[NSRunLoop(NSRunLoop) runMode:beforeDate:]
6 Foundation              -[NSRunLoop(NSRunLoop) runUntilDate:]
7 UIKitCore               -[UIEventFetcher threadMain]
8 Foundation              ___NSThread__start__
9 libsystem_pthread.dylib __pthread_start

Thread 2
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 libsystem_kernel.dylib  _thread_suspend
3 BlueWallet              ksmachexc_i_handleExceptions (BSG_KSCrashSentry_MachException.c:221:9)
4 libsystem_pthread.dylib __pthread_start

Thread 3
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 BlueWallet              ksmachexc_i_handleExceptions (BSG_KSCrashSentry_MachException.c:228:28)
3 libsystem_pthread.dylib __pthread_start

Thread 4
0 libsystem_kernel.dylib  _semaphore_timedwait_trap
1 libdispatch.dylib       __dispatch_sema4_timedwait
2 libdispatch.dylib       __dispatch_semaphore_wait_slow
3 BlueWallet              -[BSGAppHangDetector detectAppHangs] (BSGAppHangDetector.m:121:13)
4 Foundation              ___NSThread__start__
5 libsystem_pthread.dylib __pthread_start

Thread 5
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 CoreFoundation          ___CFRunLoopServiceMachPort
3 CoreFoundation          ___CFRunLoopRun
4 CoreFoundation          _CFRunLoopRunSpecific
5 BlueWallet              +[RCTCxxBridge runRunLoop] (RCTCxxBridge.mm:308:12)
6 Foundation              ___NSThread__start__
7 libsystem_pthread.dylib __pthread_start

Thread 6
0 libsystem_kernel.dylib  ___psynch_cvwait
1 libsystem_pthread.dylib __pthread_cond_wait
2 libc++.1.dylib          std::__1::condition_variable::__do_timed_wait(std::__1::unique_lock<std::__1::mutex>&, std::__1::chrono::time_point<std::__1::chrono::system_clock, std::__1::chrono::duration<long long, std::__1::ratio<1l, 1000000000l> > >)
3 JavaScriptCore          bmalloc::Scavenger::threadRunLoop()
4 JavaScriptCore          bmalloc::Scavenger::threadEntryPoint(bmalloc::Scavenger*)
5 JavaScriptCore          void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, void (*)(bmalloc::Scavenger*), bmalloc::Scavenger*> >(void*)
6 libsystem_pthread.dylib __pthread_start

Thread 7
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 CoreFoundation          ___CFRunLoopServiceMachPort
3 CoreFoundation          ___CFRunLoopRun
4 CoreFoundation          _CFRunLoopRunSpecific
5 CoreFoundation          _CFRunLoopRun
6 CoreMotion              CLMotionActivity::isTypeInVehicle(CLMotionActivity::Type)
7 libsystem_pthread.dylib __pthread_start

Thread 8
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 CoreFoundation          ___CFRunLoopServiceMachPort
3 CoreFoundation          ___CFRunLoopRun
4 CoreFoundation          _CFRunLoopRunSpecific
5 CFNetwork               __CFURLStorageSessionCopyIdentifier
6 Foundation              ___NSThread__start__
7 libsystem_pthread.dylib __pthread_start

Thread 9
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 CoreFoundation          ___CFRunLoopServiceMachPort
3 CoreFoundation          ___CFRunLoopRun
4 CoreFoundation          _CFRunLoopRunSpecific
5 AudioSession            CADeprecated::GenericRunLoopThread::Entry(void*)
6 AudioSession            CADeprecated::CAPThread::Entry(CADeprecated::CAPThread*)
7 libsystem_pthread.dylib __pthread_start

Thread 10
0 libsystem_kernel.dylib  _mach_msg_trap
1 libsystem_kernel.dylib  _mach_msg
2 CoreFoundation          ___CFRunLoopServiceMachPort
3 CoreFoundation          ___CFRunLoopRun
4 CoreFoundation          _CFRunLoopRunSpecific
5 Foundation              -[NSRunLoop(NSRunLoop) runMode:beforeDate:]
6 BlueWallet              +[GCDAsyncSocket cfstreamThread:] (GCDAsyncSocket.m:7686:25)
7 Foundation              ___NSThread__start__
8 libsystem_pthread.dylib __pthread_start

Thread 11
0 libsystem_kernel.dylib  _select$DARWIN_EXTSN
1 CoreFoundation          ___CFSocketManager
2 libsystem_pthread.dylib __pthread_start

Thread 12
0 unknown file unknown method

Thread 13
0 libsystem_kernel.dylib  _kevent
1 BlueWallet              realm::_impl::ExternalCommitHelper::listen() (BlueWallet)
2 BlueWallet              void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, realm::_impl::ExternalCommitHelper::ExternalCommitHelper(realm::_impl::RealmCoordinator&)::$_0> >(void*) (BlueWallet)
3 libsystem_pthread.dylib __pthread_start

Thread 14
0 unknown file unknown method

Thread 15
0 libsystem_blocks.dylib  __Block_copy
1 libnetwork.dylib        _nw_path_necp_update_evaluator
2 libnetwork.dylib        _nw_path_necp_check_for_updates
3 libdispatch.dylib       __dispatch_client_callout
4 libdispatch.dylib       __dispatch_continuation_pop
5 libdispatch.dylib       __dispatch_source_invoke
6 libdispatch.dylib       __dispatch_workloop_invoke
7 libdispatch.dylib       __dispatch_workloop_worker_thread
8 libsystem_pthread.dylib __pthread_wqthread

Thread 16
0 unknown file unknown method

Thread 17
0 unknown file unknown method

Thread 18
0 unknown file unknown method

Thread 19
0 BlueWallet              ___ZN5realm4util12_GLOBAL__N_122ReclaimerThreadStopperD2Ev_block_invoke (BlueWallet)
1 libdispatch.dylib       __dispatch_client_callout
2 libdispatch.dylib       __dispatch_continuation_pop
3 libdispatch.dylib       __dispatch_source_invoke
4 libdispatch.dylib       __dispatch_lane_serial_drain
5 libdispatch.dylib       __dispatch_lane_invoke
6 libdispatch.dylib       __dispatch_workloop_worker_thread
7 libsystem_pthread.dylib __pthread_wqthread

Thread 20
0  libsystem_kernel.dylib  ___ulock_wait
1  libdispatch.dylib       __dlock_wait
2  libdispatch.dylib       __dispatch_thread_event_wait_slow
3  libdispatch.dylib       ___DISPATCH_WAIT_FOR_QUEUE__
4  libdispatch.dylib       __dispatch_sync_f_slow
5  UIKitCore               ___37-[_UIRemoteKeyboards startConnection]_block_invoke_3
6  CoreFoundation          ___invoking___
7  CoreFoundation          -[NSInvocation invoke]
8  Foundation              ___NSXPCCONNECTION_IS_CALLING_OUT_TO_REPLY_BLOCK__
9  Foundation              -[NSXPCConnection _decodeAndInvokeReplyBlockWithEvent:sequence:replyInfo:]
10 Foundation              ___88-[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:]_block_invoke_3
11 libxpc.dylib            __xpc_connection_reply_callout
12 libxpc.dylib            __xpc_connection_call_reply_async
13 libdispatch.dylib       __dispatch_client_callout3
14 libdispatch.dylib       __dispatch_mach_msg_async_reply_invoke
15 libdispatch.dylib       __dispatch_lane_serial_drain
16 libdispatch.dylib       __dispatch_lane_invoke
17 libdispatch.dylib       __dispatch_workloop_worker_thread
18 libsystem_pthread.dylib __pthread_wqthread

Thread 21
0 libsystem_kernel.dylib  _syscall_thread_switch
1 JavaScriptCore          JSC::Heap::resumeThePeriphery()
2 JavaScriptCore          JSC::Heap::finishChangingPhase(JSC::GCConductor)
3 JavaScriptCore          JSC::Heap::runFixpointPhase(JSC::GCConductor)
4 JavaScriptCore          JSC::Heap::runCurrentPhase(JSC::GCConductor, JSC::CurrentThreadState*)
5 JavaScriptCore          JSC::Heap::HeapThread::work()
6 JavaScriptCore          WTF::Detail::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0, void>::call()
7 JavaScriptCore          WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*)
8 JavaScriptCore          WTF::wtfThreadEntryPoint(void*)
9 libsystem_pthread.dylib __pthread_start

Thread 22
0  JavaScriptCore          JSC::JSLexicalEnvironment::visitChildren(JSC::JSCell*, JSC::SlotVisitor&)
1  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)::$_3::operator()(JSC::MarkStackArray&) const
2  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)
3  JavaScriptCore          JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, WTF::MonotonicTime)
4  JavaScriptCore          WTF::SharedTaskFunctor<void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_18>::run()
5  JavaScriptCore          WTF::ParallelHelperClient::runTask(WTF::RefPtr<WTF::SharedTask<void ()>, WTF::RawPtrTraits<WTF::SharedTask<void ()> >, WTF::DefaultRefDerefTraits<WTF::SharedTask<void ()> > > const&)
6  JavaScriptCore          WTF::ParallelHelperPool::Thread::work()
7  JavaScriptCore          WTF::Detail::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0, void>::call()
8  JavaScriptCore          WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*)
9  JavaScriptCore          WTF::wtfThreadEntryPoint(void*)
10 libsystem_pthread.dylib __pthread_start

Thread 23
0  JavaScriptCore          JSC::SlotVisitor::appendHiddenSlow(JSC::JSCell*, WTF::Dependency)
1  JavaScriptCore          JSC::Structure* JSC::JSObject::visitButterflyImpl<JSC::SlotVisitor>(JSC::SlotVisitor&)::{lambda(unsigned char)#1}::operator()(unsigned char) const
2  JavaScriptCore          JSC::JSObject::visitChildren(JSC::JSCell*, JSC::SlotVisitor&)
3  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)::$_3::operator()(JSC::MarkStackArray&) const
4  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)
5  JavaScriptCore          JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, WTF::MonotonicTime)
6  JavaScriptCore          WTF::SharedTaskFunctor<void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_18>::run()
7  JavaScriptCore          WTF::ParallelHelperClient::runTask(WTF::RefPtr<WTF::SharedTask<void ()>, WTF::RawPtrTraits<WTF::SharedTask<void ()> >, WTF::DefaultRefDerefTraits<WTF::SharedTask<void ()> > > const&)
8  JavaScriptCore          WTF::ParallelHelperPool::Thread::work()
9  JavaScriptCore          WTF::Detail::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0, void>::call()
10 JavaScriptCore          WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*)
11 JavaScriptCore          WTF::wtfThreadEntryPoint(void*)
12 libsystem_pthread.dylib __pthread_start

Thread 24
0  JavaScriptCore          JSC::JSFinalObject::visitChildren(JSC::JSCell*, JSC::SlotVisitor&)
1  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)::$_3::operator()(JSC::MarkStackArray&) const
2  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)
3  JavaScriptCore          JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, WTF::MonotonicTime)
4  JavaScriptCore          WTF::SharedTaskFunctor<void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_18>::run()
5  JavaScriptCore          WTF::ParallelHelperClient::runTask(WTF::RefPtr<WTF::SharedTask<void ()>, WTF::RawPtrTraits<WTF::SharedTask<void ()> >, WTF::DefaultRefDerefTraits<WTF::SharedTask<void ()> > > const&)
6  JavaScriptCore          WTF::ParallelHelperPool::Thread::work()
7  JavaScriptCore          WTF::Detail::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0, void>::call()
8  JavaScriptCore          WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*)
9  JavaScriptCore          WTF::wtfThreadEntryPoint(void*)
10 libsystem_pthread.dylib __pthread_start

Thread 25
0  JavaScriptCore          JSC::SlotVisitor::appendHiddenSlow(JSC::JSCell*, WTF::Dependency)
1  JavaScriptCore          JSC::JSFinalObject::visitChildren(JSC::JSCell*, JSC::SlotVisitor&)
2  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)::$_3::operator()(JSC::MarkStackArray&) const
3  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)
4  JavaScriptCore          JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, WTF::MonotonicTime)
5  JavaScriptCore          WTF::SharedTaskFunctor<void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_18>::run()
6  JavaScriptCore          WTF::ParallelHelperClient::runTask(WTF::RefPtr<WTF::SharedTask<void ()>, WTF::RawPtrTraits<WTF::SharedTask<void ()> >, WTF::DefaultRefDerefTraits<WTF::SharedTask<void ()> > > const&)
7  JavaScriptCore          WTF::ParallelHelperPool::Thread::work()
8  JavaScriptCore          WTF::Detail::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0, void>::call()
9  JavaScriptCore          WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*)
10 JavaScriptCore          WTF::wtfThreadEntryPoint(void*)
11 libsystem_pthread.dylib __pthread_start

Thread 26
0  JavaScriptCore          JSC::JSFinalObject::visitChildren(JSC::JSCell*, JSC::SlotVisitor&)
1  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)::$_3::operator()(JSC::MarkStackArray&) const
2  JavaScriptCore          JSC::SlotVisitor::drain(WTF::MonotonicTime)
3  JavaScriptCore          JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, WTF::MonotonicTime)
4  JavaScriptCore          WTF::SharedTaskFunctor<void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_18>::run()
5  JavaScriptCore          WTF::ParallelHelperClient::runTask(WTF::RefPtr<WTF::SharedTask<void ()>, WTF::RawPtrTraits<WTF::SharedTask<void ()> >, WTF::DefaultRefDerefTraits<WTF::SharedTask<void ()> > > const&)
6  JavaScriptCore          WTF::ParallelHelperPool::Thread::work()
7  JavaScriptCore          WTF::Detail::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0, void>::call()
8  JavaScriptCore          WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*)
9  JavaScriptCore          WTF::wtfThreadEntryPoint(void*)
10 libsystem_pthread.dylib __pthread_start

Steps to reproduce

Steps to reproduce the behavior:

1. keep the app in the background for a while
2. open the app
3. small chance of an immediate crash

Screenshots
If applicable, add screenshots to help explain your problem.

Relevant information

OS	ios 15.0
react-native	0.64.2
react-native-tcp-socket	5.3.1

[Overtorment]

screenshots from bugsnag:

[Overtorment]

[Rapsssito]

@Overtorment, thanks for the feedback! iOS has a very special way of dealing with sockets when an app is in the background, which may be the root cause of this issue. A temporary workaround would be to close all sockets when the app is going to the background. I will take a look at your error trace and improve the module error handling for this kind of situations.

I will close this issue as soon as this problem is fixed.

[Rapsssito]

@Overtorment, could you tell me if you are using an HTTPS connection and if you are sending data when the app is in the background?

[Overtorment]

yes, connection is https.
as for background, network module is not aware of such thing. i.e. state change is not handled in any way (at least not in the networking module)

[liuguanlin]

Same crash，Do you have a solution

[Rapsssito]

@liuguanlin, I am sorry but I was not able to reproduce this issue. Could you create a minimal reproducible code example?

[liuguanlin]

@liuguanlin, I am sorry but I was not able to reproduce this issue. Could you create a minimal reproducible code example?

Bugly collected it, but I didn't reproduce it myself

[siarheipashkevich]

I've the same issue also on iOS

[sergeushenecz]

I have same issue.

[sergeushenecz]

@Rapsssito Could you please check?

[siarheipashkevich]

@Rapsssito for reproducing this issue you need:

• create server in the app
• move app to the background
• connect to the server (when the app in background)
• open the app (there is error is happened and app is crashed (closed))

[zameschua]

I managed to reliably reproduce the above issue

1. create server
2. background the app
3. connect to server while server app is backgrounded
4. open the app

Not 100% sure if it's a related issue, but I managed to get a NSInvalidArgumentException on the TCP server by repeatedly connecting and disconnecting to a TCP server from another TCP socket