iOS Crash in WWW::FeedUnityWebStream(bool) with bad address 0x0

Crash #3

My game is live, and some players are experiencing crashes. I cannot reproduce any of them, so all I have to go on are traces reported via Crashlytics. It looks like something is trying to access the null memory address but I'm not sure how to decipher the rest. Any help is appreciated.

Only happens on iOS
Crashes with EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x0000000000000000
Crashes in: WWW::FeedUnityWebStream(bool) / com.unity3d.WebOperationQueue :: NSOperation 0x17485f020 (QOS: DEFAULT)
Built with IL2CPP

Code (CSharp):

1. Crashed: com.unity3d.WebOperationQueue :: NSOperation 0x17485f020 (QOS: DEFAULT)
2. 0  matchdragons                   0x10093b930 WWW::FeedUnityWebStream(bool) + 4305418544
3. 1  matchdragons                   0x100c281c8 iPhoneWWWDownloadBuffer::OnCompleteContent() + 4308484552
4. 2  matchdragons                   0x100c06b90 UnityReportWWWFinishedLoadingData + 4308347792
5. 3  matchdragons                   0x100037c6c -[UnityWWWConnectionDelegate connection:didFailWithError:] (WWWConnection.mm:239)
6. 4  CFNetwork                      0x194a112cc __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke + 80
7. 5  CFNetwork                      0x194a1125c -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 200
8. 6  CFNetwork                      0x194a1141c -[NSURLConnectionInternal _withConnectionAndDelegate:] + 56
9. 7  CFNetwork                      0x1949cf98c _NSURLConnectionDidFail(_CFURLConnection*, __CFError*, void const*) + 76
10. 8  CFNetwork                      0x1949338e0 ___ZN27URLConnectionClient_Classic17_delegate_didFailEP9__CFErrorU13block_pointerFvvE_block_invoke + 112
11. 9  CFNetwork                      0x1949314bc ___ZN27URLConnectionClient_Classic18_withDelegateAsyncEPKcU13block_pointerFvP16_CFURLConnectionPK33CFURLConnectionClientCurrent_VMaxE_block_invoke_2 + 108
12. 10 libdispatch.dylib              0x19303e1bc _dispatch_client_callout + 16
13. 11 libdispatch.dylib              0x193049ab0 _dispatch_block_invoke_direct + 376
14. 12 CFNetwork                      0x1949ee2a8 RunloopBlockContext::_invoke_block(void const*, void*) + 36
15. 13 CoreFoundation                 0x19408dc18 CFArrayApplyFunction + 68
16. 14 CFNetwork                      0x1949ee18c RunloopBlockContext::perform() + 136
17. 15 CFNetwork                      0x1949ef4b4 MultiplexerSource::perform() + 312
18. 16 CFNetwork                      0x1949ef220 MultiplexerSource::_perform(void*) + 64
19. 17 CoreFoundation                 0x194162b5c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
20. 18 CoreFoundation                 0x1941624a4 __CFRunLoopDoSources0 + 524
21. 19 CoreFoundation                 0x1941600a4 __CFRunLoopRun + 804
22. 20 CoreFoundation                 0x19408e2b8 CFRunLoopRunSpecific + 444
23. 21 Foundation                     0x194bcb26c -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 304
24. 22 Foundation                     0x194c1faa0 -[NSRunLoop(NSRunLoop) run] + 88
25. 23 matchdragons                   0x100038bd8 __UnitySendWWWConnection_block_invoke_2 (WWWConnection.mm:362)
26. 24 Foundation                     0x194ca3fb0 __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 16
27. 25 Foundation                     0x194be8aa8 -[NSBlockOperation main] + 96
28. 26 Foundation                     0x194bd90a4 -[__NSOperationInternal _start:] + 620
29. 27 Foundation                     0x194ca635c __NSOQSchedule_f + 228
30. 28 libdispatch.dylib              0x19303e1bc _dispatch_client_callout + 16
31. 29 libdispatch.dylib              0x19304c3dc _dispatch_queue_serial_drain + 928
32. 30 libdispatch.dylib              0x1930419a4 _dispatch_queue_invoke + 652
33. 31 libdispatch.dylib              0x19304e34c _dispatch_root_queue_drain + 572
34. 32 libdispatch.dylib              0x19304e0ac _dispatch_worker_thread3 + 124
35. 33 libsystem_pthread.dylib        0x1932472a0 _pthread_wqthread + 1288
36. 34 libsystem_pthread.dylib        0x193246d8c start_wqthread + 4

 

I'm seeing this exact crash as well. Unity 5.4.3 for me. Are you using Unity Ads? Other than that I'm not doing any networking, so I suspect it may have to do with that.

 

I'm not using Unity Ads. But I am using Unity Analytics.
I also have a call that opens a web page to my discussion forums, but I don't think that's the cause since I'd see that in my stack trace.

 

I'm also using "UniRate" from the asset store, and one curious note of all the players that choose to "Rate" the game, only about 3/5 of those turn into actual ratings. I don't know if the others either change their mind, or maybe there's an error with using a web service in UniRate to bring up the ratings pages since it uses standard HTML links.

 

For reference, I've found this thread which may be the same issue, and a Unity dev is working through it:
https://forum.unity3d.com/threads/ios-unityreportwwwreceiveddata-crash.339058/