问题
I am Getting [_WebSafeForwarder forwardInvocation:] and crash report as following on crashlytics. Unable to reproduce the same condition in my code. I added webview.delegate = nil and [webview stopLoading] in each and every -(void)dealloc method where ever UIWebview is present still getting following crash.
#0. Crashed: com.apple.main-thread
0 libobjc.A.dylib 0x24deba86 objc_msgSend + 5
1 WebKitLegacy 0x29945e17 -[_WebSafeForwarder forwardInvocation:] + 190
2 CoreFoundation 0x25624f4d ___forwarding___ + 352
3 CoreFoundation 0x2554f298 _CF_forwarding_prep_0 + 24
4 CoreFoundation 0x25626664 __invoking___ + 68
5 CoreFoundation 0x2554b8bd -[NSInvocation invoke] + 292
6 WebCore 0x28d6b84b HandleDelegateSource(void*) + 90
7 CoreFoundation 0x255e39e7 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
8 CoreFoundation 0x255e3569 __CFRunLoopDoSources0 + 344
9 CoreFoundation 0x255e193f __CFRunLoopRun + 806
10 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
11 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
12 UIFoundation 0x29bb5837 -[NSHTMLReader _loadUsingWebKit] + 2038
13 Foundation 0x25e4e887 __NSThreadPerformPerform + 386
14 CoreFoundation 0x255e39e7 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
15 CoreFoundation 0x255e3569 __CFRunLoopDoSources0 + 344
16 CoreFoundation 0x255e193f __CFRunLoopRun + 806
17 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
18 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
19 GraphicsServices 0x26b4caf9 GSEventRunModal + 160
20 UIKit 0x29c68435 UIApplicationMain + 144
21 MyProjectName 0x1446e5 main (main.m:14)
22 libdispatch.dylib 0x251dc873 (Missing)
--
#0. Crashed: com.apple.main-thread
0 libobjc.A.dylib 0x24deba86 objc_msgSend + 5
1 WebKitLegacy 0x29945e17 -[_WebSafeForwarder forwardInvocation:] + 190
2 CoreFoundation 0x25624f4d ___forwarding___ + 352
3 CoreFoundation 0x2554f298 _CF_forwarding_prep_0 + 24
4 CoreFoundation 0x25626664 __invoking___ + 68
5 CoreFoundation 0x2554b8bd -[NSInvocation invoke] + 292
6 WebCore 0x28d6b84b HandleDelegateSource(void*) + 90
7 CoreFoundation 0x255e39e7 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
8 CoreFoundation 0x255e3569 __CFRunLoopDoSources0 + 344
9 CoreFoundation 0x255e193f __CFRunLoopRun + 806
10 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
11 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
12 UIFoundation 0x29bb5837 -[NSHTMLReader _loadUsingWebKit] + 2038
13 Foundation 0x25e4e887 __NSThreadPerformPerform + 386
14 CoreFoundation 0x255e39e7 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
15 CoreFoundation 0x255e3569 __CFRunLoopDoSources0 + 344
16 CoreFoundation 0x255e193f __CFRunLoopRun + 806
17 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
18 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
19 GraphicsServices 0x26b4caf9 GSEventRunModal + 160
20 UIKit 0x29c68435 UIApplicationMain + 144
21 MyProjectName 0x1446e5 main (main.m:14)
22 libdispatch.dylib 0x251dc873 (Missing)
#2. com.twitter.crashlytics.ios.MachExceptionServer
0 MyProjectName 0x157cdd CLSProcessRecordAllThreads + 1015005
1 MyProjectName 0x157cdd CLSProcessRecordAllThreads + 1015005
2 MyProjectName 0x157ef5 CLSProcessRecordAllThreads + 1015541
3 MyProjectName 0x14c52b CLSHandler + 967979
4 MyProjectName 0x148249 CLSMachExceptionServer + 950857
5 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
6 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
7 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#3. GAIThread
0 libsystem_kernel.dylib 0x2529b8a8 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x2529b6a9 mach_msg + 40
2 CoreFoundation 0x255e36ad __CFRunLoopServiceMachPort + 136
3 CoreFoundation 0x255e1a33 __CFRunLoopRun + 1050
4 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
5 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
6 Foundation 0x25d7d42d -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 268
7 Foundation 0x25dcbd75 -[NSRunLoop(NSRunLoop) run] + 80
8 MyProjectName 0x1d58c5 +[GAI threadMain:] + 1530053
9 Foundation 0x25e4e64d __NSThread__start__ + 1144
10 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
11 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
12 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#4. com.apple.NSURLConnectionLoader
0 libsystem_kernel.dylib 0x2529b8a8 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x2529b6a9 mach_msg + 40
2 CoreFoundation 0x255e36ad __CFRunLoopServiceMachPort + 136
3 CoreFoundation 0x255e1a33 __CFRunLoopRun + 1050
4 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
5 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
6 CFNetwork 0x25b85c47 +[NSURLConnection(Loader) _resourceLoadLoop:] + 486
7 Foundation 0x25e4e64d __NSThread__start__ + 1144
8 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
9 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
10 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#5. com.apple.CFSocket.private
0 libsystem_kernel.dylib 0x252afeec __select + 20
1 CoreFoundation 0x255e8b51 __CFSocketManager + 572
2 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
3 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
4 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#6. AFNetworking
0 libsystem_kernel.dylib 0x2529b8a8 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x2529b6a9 mach_msg + 40
2 CoreFoundation 0x255e36ad __CFRunLoopServiceMachPort + 136
3 CoreFoundation 0x255e1a33 __CFRunLoopRun + 1050
4 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
5 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
6 Foundation 0x25d7d42d -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 268
7 Foundation 0x25dcbd75 -[NSRunLoop(NSRunLoop) run] + 80
8 MyProjectName 0x29d30f +[AFURLConnectionOperation networkRequestThreadEntryPoint:] (AFURLConnectionOperation.m:168)
9 Foundation 0x25e4e64d __NSThread__start__ + 1144
10 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
11 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
12 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#7. WebThread
0 libsystem_kernel.dylib 0x252af998 __psynch_cvwait + 24
1 libsystem_pthread.dylib 0x253541a5 _pthread_cond_wait + 536
2 libsystem_pthread.dylib 0x253550f9 pthread_cond_timedwait + 44
3 WebCore 0x28d57f57 SendDelegateMessage(NSInvocation*) + 678
4 WebKitLegacy 0x29978265 CallFrameLoadDelegate(void (*)(), WebView*, objc_selector*, objc_object*) + 172
5 WebKitLegacy 0x29947877 WebFrameLoaderClient::dispatchDidFinishLoad() + 158
6 WebCore 0x28d290af WebCore::FrameLoader::checkLoadCompleteForThisFrame() + 382
7 WebCore 0x28d28e75 WebCore::FrameLoader::checkLoadComplete() + 280
8 WebCore 0x28d55bf1 WebCore::FrameLoader::checkCompleted() + 316
9 WebCore 0x28d5504b WebCore::FrameLoader::finishedParsing() + 102
10 WebCore 0x28d54f59 WebCore::Document::finishedParsing() + 312
11 WebCore 0x28d5270b WebCore::HTMLDocumentParser::prepareToStopParsing() + 118
12 WebCore 0x28dddbcb WebCore::HTMLDocumentParser::resumeParsingAfterYield() + 102
13 WebCore 0x28cff4a1 WebCore::ThreadTimers::sharedTimerFiredInternal() + 136
14 WebCore 0x28cff3f5 WebCore::timerFired(__CFRunLoopTimer*, void*) + 28
15 CoreFoundation 0x255e4177 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 14
16 CoreFoundation 0x255e3da9 __CFRunLoopDoTimer + 936
17 CoreFoundation 0x255e1bf5 __CFRunLoopRun + 1500
18 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
19 CoreFoundation 0x2552ffbd CFRunLoopRunInMode + 108
20 WebCore 0x28d457b7 RunWebThread(void*) + 422
21 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
22 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
23 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#8. JavaScriptCore::Marking
0 libsystem_kernel.dylib 0x252af998 __psynch_cvwait + 24
1 libsystem_pthread.dylib 0x253541a5 _pthread_cond_wait + 536
2 libsystem_pthread.dylib 0x253550b9 pthread_cond_wait + 40
3 libc++.1.dylib 0x24d7469d std::__1::condition_variable::wait(std::__1::unique_lock<std::__1::mutex>&) + 36
4 JavaScriptCore 0x2891a781 JSC::GCThread::waitForNextPhase() + 104
5 JavaScriptCore 0x2891a7ef JSC::GCThread::gcThreadMain() + 62
6 JavaScriptCore 0x287269e1 WTF::threadEntryPoint(void*) + 148
7 JavaScriptCore 0x2872693f WTF::wtfThreadEntryPoint(void*) + 14
8 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
9 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
10 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#9. NSOperationQueue 0x15e6cc20 :: NSOperation 0x15d230e0 (QOS: USER_INTERACTIVE)
0 libsystem_kernel.dylib 0x2529b8f8 semaphore_wait_trap + 8
1 libsystem_platform.dylib 0x2534f289 _os_semaphore_wait + 12
2 libdispatch.dylib 0x251bcc6d _dispatch_barrier_sync_f_slow + 372
3 MyProjectName 0x27dd8f __69-[SDWebImageManager downloadImageWithURL:options:progress:completed:]_block_invoke98 (SDWebImageManager.m:189)
4 MyProjectName 0x275e71 __72-[SDWebImageDownloader downloadImageWithURL:options:progress:completed:]_block_invoke93 (SDWebImageDownloader.m:163)
5 MyProjectName 0x27a8fb -[SDWebImageDownloaderOperation connection:didFailWithError:] (SDWebImageDownloaderOperation.m:419)
6 CFNetwork 0x25c683a1 __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke + 56
7 CFNetwork 0x25c68359 -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 184
8 CFNetwork 0x25c6847d -[NSURLConnectionInternal _withConnectionAndDelegate:] + 36
9 CFNetwork 0x25c44125 _NSURLConnectionDidFail(_CFURLConnection*, __CFError*, void const*) + 84
10 CFNetwork 0x25be3203 ___ZN27URLConnectionClient_Classic17_delegate_didFailEP9__CFErrorU13block_pointerFvvE_block_invoke + 86
11 CFNetwork 0x25be1a83 ___ZN27URLConnectionClient_Classic18_withDelegateAsyncEPKcU13block_pointerFvP16_CFURLConnectionPK33CFURLConnectionClientCurrent_VMaxE_block_invoke_2 + 70
12 libdispatch.dylib 0x251b3cab _dispatch_client_callout + 22
13 libdispatch.dylib 0x251bb543 _dispatch_block_invoke + 450
14 CFNetwork 0x25b13e83 RunloopBlockContext::_invoke_block(void const*, void*) + 18
15 CoreFoundation 0x2552fc09 CFArrayApplyFunction + 36
16 CFNetwork 0x25b13d6b RunloopBlockContext::perform() + 182
17 CFNetwork 0x25b13c35 MultiplexerSource::perform() + 216
18 CFNetwork 0x25b13ac9 MultiplexerSource::_perform(void*) + 48
19 CoreFoundation 0x255e39e7 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
20 CoreFoundation 0x255e35d7 __CFRunLoopDoSources0 + 454
21 CoreFoundation 0x255e193f __CFRunLoopRun + 806
22 CoreFoundation 0x255301c9 CFRunLoopRunSpecific + 516
23 CoreFoundation 0x25570f23 CFRunLoopRun + 98
24 MyProjectName 0x27779b -[SDWebImageDownloaderOperation start] (SDWebImageDownloaderOperation.m:117)
25 Foundation 0x25e38b0d __NSOQSchedule_f + 192
26 libdispatch.dylib 0x251bde7f _dispatch_queue_drain + 1762
27 libdispatch.dylib 0x251b6e17 _dispatch_queue_invoke + 282
28 libdispatch.dylib 0x251bf20d _dispatch_root_queue_drain + 400
29 libdispatch.dylib 0x251bf07b _dispatch_worker_thread3 + 94
30 libsystem_pthread.dylib 0x25352e0d _pthread_wqthread + 1024
31 libsystem_pthread.dylib 0x253529fc start_wqthread + 8
#10. com.apple.root.default-qos
0 libsystem_kernel.dylib 0x252af998 __psynch_cvwait + 24
1 libsystem_pthread.dylib 0x253541a5 _pthread_cond_wait + 536
2 libsystem_pthread.dylib 0x253550b9 pthread_cond_wait + 40
3 Foundation 0x25dc840f -[NSCondition wait] + 194
4 Foundation 0x25d8f40b -[NSObject(NSThreadPerformAdditions) performSelector:onThread:withObject:waitUntilDone:modes:] + 850
5 Foundation 0x25d92be1 -[NSObject(NSThreadPerformAdditions) performSelectorOnMainThread:withObject:waitUntilDone:] + 136
6 UIFoundation 0x29bb611f -[NSHTMLReader _load] + 386
7 UIFoundation 0x29bb6b21 -[NSHTMLReader attributedString] + 24
8 UIFoundation 0x29b5ac35 _NSReadAttributedStringFromURLOrData + 5304
9 UIFoundation 0x29b596f5 -[NSAttributedString(NSAttributedStringUIFoundationAdditions) initWithData:options:documentAttributes:error:] + 116
10 MyProjectName 0x19cecf -[MyStaticLibrary handleHTMLCharactersForTitle:] (MyStaticLibrary.m:3132)
11 MyProjectName 0x1a8905 __47-[MyNetworkRequest onHTTPSuccessWithResponse:]_block_invoke143 (MyNetworkRequest.m:484)
12 libdispatch.dylib 0x251b3cbf _dispatch_call_block_and_release + 10
13 libdispatch.dylib 0x251bf6a1 _dispatch_root_queue_drain + 1572
14 libdispatch.dylib 0x251bf07b _dispatch_worker_thread3 + 94
15 libsystem_pthread.dylib 0x25352e0d _pthread_wqthread + 1024
16 libsystem_pthread.dylib 0x253529fc start_wqthread + 8
#11. Thread
0 libsystem_kernel.dylib 0x252afffc __semwait_signal + 24
1 libsystem_c.dylib 0x25203bcd nanosleep + 172
2 libc++.1.dylib 0x24db38f5 std::__1::this_thread::sleep_for(std::__1::chrono::duration<long long, std::__1::ratio<1ll, 1000000000ll> > const&) + 136
3 JavaScriptCore 0x28ad9b01 bmalloc::Heap::scavenge(std::__1::unique_lock<bmalloc::StaticMutex>&, std::__1::chrono::duration<long long, std::__1::ratio<1ll, 1000ll> >) + 256
4 JavaScriptCore 0x28ad98eb bmalloc::Heap::concurrentScavenge() + 78
5 JavaScriptCore 0x28adb7b7 bmalloc::AsyncTask<bmalloc::Heap, void (bmalloc::Heap::*)()>::entryPoint() + 98
6 JavaScriptCore 0x28adb751 bmalloc::AsyncTask<bmalloc::Heap, void (bmalloc::Heap::*)()>::pthreadEntryPoint(void*) + 8
7 libsystem_pthread.dylib 0x25354c7f _pthread_body + 138
8 libsystem_pthread.dylib 0x25354bf3 _pthread_start + 110
9 libsystem_pthread.dylib 0x25352a08 thread_start + 8
#12. Thread
0 libsystem_pthread.dylib 0x253529f4 start_wqthread + 14
#13. Thread
0 libsystem_kernel.dylib 0x252b0864 __workq_kernreturn + 8
1 libsystem_pthread.dylib 0x25352e19 _pthread_wqthread + 1036
2 libsystem_pthread.dylib 0x253529fc start_wqthread + 8
#14. Thread
0 libsystem_kernel.dylib 0x252b0864 __workq_kernreturn + 8
1 libsystem_pthread.dylib 0x25352e19 _pthread_wqthread + 1036
2 libsystem_pthread.dylib 0x253529fc start_wqthread + 8
#15. PLClientLoggingFlushQueue
0 libsystem_platform.dylib 0x2534e96a _platform_memmove + 105
1 CoreFoundation 0x2553f0c7 CFStringGetBytes + 634
2 CoreFoundation 0x2553f0c7 CFStringGetBytes + 634
3 CoreFoundation 0x25677ab9 __writeObject15 + 324
4 CoreFoundation 0x2567841d __writeObject15 + 2728
5 CoreFoundation 0x2567841d __writeObject15 + 2728
6 CoreFoundation 0x2567841d __writeObject15 + 2728
7 CoreFoundation 0x2567841d __writeObject15 + 2728
8 CoreFoundation 0x2567841d __writeObject15 + 2728
9 CoreFoundation 0x256777ad __CFBinaryPlistWrite15 + 152
10 CoreFoundation 0x255729cf _CFXPCCreateXPCMessageWithCFObject + 118
11 PowerLog 0x2707ab4f -[PLClientLogger xpcSendMessage:withClientID:withKey:withPayload:] + 86
12 PowerLog 0x2707bd85 -[PLClientLogger batchTasksCacheFlush] + 500
13 libdispatch.dylib 0x251b3cbf _dispatch_call_block_and_release + 10
14 libdispatch.dylib 0x251bd3cf _dispatch_after_timer_callback + 66
15 libdispatch.dylib 0x251c65bb _dispatch_source_latch_and_call + 2042
16 libdispatch.dylib 0x251b5bff _dispatch_source_invoke + 738
17 libdispatch.dylib 0x251bd9ed _dispatch_queue_drain + 592
18 libdispatch.dylib 0x251b6e17 _dispatch_queue_invoke + 282
19 libdispatch.dylib 0x251bf20d _dispatch_root_queue_drain + 400
20 libdispatch.dylib 0x251bf07b _dispatch_worker_thread3 + 94
21 libsystem_pthread.dylib 0x25352e0d _pthread_wqthread + 1024
22 libsystem_pthread.dylib 0x253529fc start_wqthread + 8
回答1:
I have the same issue, I used [NSAttributedString alloc] initWithData to load the HTML string on a label. My crashes often happened when the app switch between Background mode and Foreground mode.
I got some tips from Apple's documentation, I think this might be useful.
Following are the discussion on Apple's NSAttributedstring doc：
The HTML importer should not be called from a background thread (that is, the options dictionary includes NSDocumentTypeDocumentAttribute with a value of NSHTMLTextDocumentType). It will try to synchronize with the main thread, fail, and time out. Calling it from the main thread works (but can still time out if the HTML contains references to external resources, which should be avoided at all costs). The HTML import mechanism is meant for implementing something like markdown (that is, text styles, colors, and so on), not for general HTML import.
来源：https://stackoverflow.com/questions/38712772/unable-to-reproduce-webkitlegacy-websafeforwarder-forwardinvocation-crash