iOS: RCTImageLoader is documented to be thread safe but the setUp code has a race

[mfazekas]

Description

According to the header docs loadImageWithURLRequest can be called from any thread.

https://github.com/facebook/react-native/blob/0bb085c7b65527717a1c2750fadc0783c8da6b78/packages/react-native/Libraries/Image/RCTImageLoaderProtocol.h#L68

But the one time setup code has race condition and multiple threads can enter the setUp method:
https://github.com/facebook/react-native/blob/0bb085c7b65527717a1c2750fadc0783c8da6b78/packages/react-native/Libraries/Image/RCTImageLoader.mm#L159-L161

This could potentially lead to crashes like this: #33592

Steps to reproduce

The reproducer at https://github.com/mfazekas/RCTImageLoaderTheadSafety has a native objetive-c class exectuted that hammers RCTImageLoader from many threads at the same time. Sometimes some crash can be reproduced that way. (Note that once the [setUp] has been called the race condition is not observable so app needs to restarted).

React Native Version

0.75.1

Affected Platforms

Runtime - iOS

Output of npx react-native info

% npx react-native info
error: unknown command 'info'
(Did you mean init?)
% npx react-native -v       
14.0.0

### Stacktrace or Logs

```text
One crash I was able to reproduce with reproduce is:

*** Terminating app due to uncaught exception 'NSGenericException', reason: '*** Collection <__NSArrayM: 0x600000c65140> was mutated while being enumerated.'
*** First throw call stack:
(
	0   CoreFoundation                      0x00000001804ac330 __exceptionPreprocess + 172
	1   libobjc.A.dylib                     0x0000000180086c58 objc_exception_throw + 72
	2   CoreFoundation                      0x00000001804ab758 +[__NSFastEnumerationEnumerator allocWithZone:] + 0
	3   ReproducerApp                       0x0000000101318938 __30-[RCTImageLoader dequeueTasks]_block_invoke + 1532
	4   libdispatch.dylib                   0x0000000103a53f40 _dispatch_call_block_and_release + 24
	5   libdispatch.dylib                   0x0000000103a55838 _dispatch_client_callout + 16
	6   libdispatch.dylib                   0x0000000103a5db2c _dispatch_lane_serial_drain + 912
	7   libdispatch.dylib                   0x0000000103a5e830 _dispatch_lane_invoke + 420
	8   libdispatch.dylib                   0x0000000103a6b240 _dispatch_root_queue_drain_deferred_wlh + 324
	9   libdispatch.dylib                   0x0000000103a6a7d4 _dispatch_workloop_worker_thread + 764
	10  libsystem_pthread.dylib             0x0000000104223814 _pthread_wqthread + 284
	11  libsystem_pthread.dylib             0x00000001042225d4 start_wqthread + 8
)

Customer is observing a different crash:

OS Version: iOS 16.2 (20C65) Report Version: 104
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Crashed Thread: 37

Application Specific Information:
release

Thread 37 Crashed:
0 libdispatch.dylib 0x365c34ab4 _os_object_release
1 Halter 0x2006f72c4 -[RCTImageLoader imageURLLoaderForURL:] (RCTImageLoader.mm:182)
2 Halter 0x2006f81b4 -[RCTImageLoader _loadImageOrDataWithURLRequest:size:scale:resizeMode:priority:attribution:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:507)
3 Halter 0x2006fa64c -[RCTImageLoader loadImageWithURLRequest:size:scale:clipped:resizeMode:priority:attribution:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:857)
4 Halter 0x2006f7a0c -[RCTImageLoader loadImageWithURLRequest:size:scale:clipped:resizeMode:priority:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:388)
5 Halter 0x2006f7904 -[RCTImageLoader loadImageWithURLRequest:size:scale:clipped:resizeMode:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:367)
6 Halter 0x20171b958 closure in RNMBXImageQueueOperation.start (RNMBXImageQueue.swift:72)
7 Halter 0x2003dfea8 thunk for closure
8 libdispatch.dylib 0x365c344b0 _dispatch_call_block_and_release
9 libdispatch.dylib 0x365c35fd8 _dispatch_client_callout
10 libdispatch.dylib 0x365c390c4 _dispatch_queue_override_invoke
11 libdispatch.dylib 0x365c47a68 _dispatch_root_queue_drain
12 libdispatch.dylib 0x365c48280 _dispatch_worker_thread2
13 libsystem_pthread.dylib 0x3f3122db8 _pthread_wqthread


Thread 29
0 libsystem_kernel.dylib 0x3d22e5aa8 __psynch_mutexwait
1 libsystem_pthread.dylib 0x3f312414c _pthread_mutex_firstfit_lock_wait
2 libsystem_pthread.dylib 0x3f312b30c _pthread_mutex_firstfit_lock_slow
3 libc++.1.dylib 0x373d209ec std::__1::mutex::lock
4 Halter 0x2006f72d8 [inlined] std::__1::unique_lock::unique_lock[abi:ue170006] (unique_lock.h:41)
5 Halter 0x2006f72d8 [inlined] std::__1::unique_lock::unique_lock[abi:ue170006] (unique_lock.h:40)
6 Halter 0x2006f72d8 -[RCTImageLoader imageURLLoaderForURL:] (RCTImageLoader.mm:186)
7 Halter 0x2006f81b4 -[RCTImageLoader _loadImageOrDataWithURLRequest:size:scale:resizeMode:priority:attribution:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:507)
8 Halter 0x2006fa64c -[RCTImageLoader loadImageWithURLRequest:size:scale:clipped:resizeMode:priority:attribution:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:857)
9 Halter 0x2006f7a0c -[RCTImageLoader loadImageWithURLRequest:size:scale:clipped:resizeMode:priority:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:388)
10 Halter 0x2006f7904 -[RCTImageLoader loadImageWithURLRequest:size:scale:clipped:resizeMode:progressBlock:partialLoadBlock:completionBlock:] (RCTImageLoader.mm:367)
11 Halter 0x20171b958 closure in RNMBXImageQueueOperation.start (RNMBXImageQueue.swift:72)
12 Halter 0x2003dfea8 thunk for closure
13 libdispatch.dylib 0x365c344b0 _dispatch_call_block_and_release
14 libdispatch.dylib 0x365c35fd8 _dispatch_client_callout
15 libdispatch.dylib 0x365c390c4 _dispatch_queue_override_invoke
16 libdispatch.dylib 0x365c47a68 _dispatch_root_queue_drain
17 libdispatch.dylib 0x365c48280 _dispatch_worker_thread2
18 libsystem_pthread.dylib 0x3f3122db8 _pthread_wqthread

### Reproducer

https://github.com/mfazekas/RCTImageLoaderTheadSafety

### Screenshots and Videos

See: https://github.com/rnmapbox/maps/issues/3589

[react-native-bot]

⚠️

Newer Version of React Native is Available!

ℹ️

You are on a supported minor version, but it looks like there's a newer patch available - 0.75.2. Please upgrade to the highest patch for your minor or latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If it does not repro, please let us know so we can close out this issue. This helps us ensure we are looking at issues that still exist in the most recent releases.

[react-native-bot]

⚠️

Newer Version of React Native is Available!

ℹ️

You are on a supported minor version, but it looks like there's a newer patch available - undefined. Please upgrade to the highest patch for your minor or latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If it does not repro, please let us know so we can close out this issue. This helps us ensure we are looking at issues that still exist in the most recent releases.