31955525: Dead lock in WebCore/WebThreadLock

[openradar-mirror]

Description

Area:
WebKit

Summary:
When UIWebView is executing some JavaScript it can run in a dead lock on the main thread, causing the whole application to hang. In the real world this is caused by some CPU intensive JavaScript. In the attached example project a simple while (true) { ... } loop in JavaScript is used to demonstrate the issue.

Steps to Reproduce:

1. Open attached project in Xcode 8.3.2
2. Run it on iPhone 7 10.3 Simulator
3. Tap on the "Open WebView" button
4. Wait 10 seconds
5. Tap on the back button
6. Wait 10 seconds
7. Tap again on the "Open WebView" button

Expected Results:
Open the WebView a second time.

Actual Results:
It does not open the WebView a second time. Instead the application hangs and is unresponsive.

You can pause the application at this point and get a stack trace of the main thread:

• thread 22108400: Swift 2.0b4: Allow if let and guard let to assign to self in failable value type initializers #1, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
  • frame #0: 0x0000000107ba0c22 libsystem_kernel.dylib__psynch_mutexwait + 10 frame #1: 0x0000000107bd5e6e libsystem_pthread.dylib_pthread_mutex_lock_wait + 100
    frame 22108390: Swift 2.0b4: Allow assignment of nil to self in failable initializers to indicate failure #2: 0x0000000107bd358d libsystem_pthread.dylib_pthread_mutex_lock_slow + 285 frame #3: 0x000000010af466d2 WebCore_WebTryThreadLock(bool) + 34
    frame 22108127: Apple Music: CarPlay does not show the For You Playlists #4: 0x000000010af47508 WebCoreWebThreadLock + 88 frame #5: 0x00000001043fb58a UIKit-[UIWebDocumentView viewportHandler:didChangeViewportSize:] + 56
    frame 22108095: Changing account in Music app requires force-quit #6: 0x000000010444c083 UIKit-[_UIWebViewportHandler update:] + 394 frame #7: 0x00000001043fd991 UIKit-[UIWebDocumentView setMinimumSize:updateCurrentViewportConfigurationSize:] + 105
    frame 22107434: Providing Generic Generator for protocol intermittently crashes compiler #8: 0x0000000104446133 UIKit-[UIWebView _updateViewSettings] + 723 frame #9: 0x0000000104445a9b UIKit-[_UIWebViewScrollView setContentInset:] + 241
    frame 22107245: Xcode 7 beta 4 (7A165t) Interface Builder ignores background color set on UITableView #10: 0x000000010425c644 UIKit-[UIViewController _setNavigationControllerContentInsetAdjustment:] + 573 frame #11: 0x00000001042a1450 UIKit-[UINavigationController navigationTransitionView:didEndTransition:fromView:toView:] + 804
    frame 22106516: watchOS 2 Beta 4: Can’t Import CoreText #12: 0x0000000104296f84 UIKit__49-[UINavigationController _startCustomTransition:]_block_invoke + 246 frame #13: 0x0000000104bf1dac UIKit-[_UIViewControllerTransitionContext completeTransition:] + 102
    frame 22105625: Mac OS X 10.11: Battery status alwasy shows "20:00 Remaining" #14: 0x00000001040ab360 UIKit__53-[_UINavigationParallaxTransition animateTransition:]_block_invoke.99 + 803 frame #15: 0x000000010417bcd4 UIKit-[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 527
    frame 22103992: Stack implemented with enum causes Abort trap: 6 #16: 0x000000010414ef07 UIKit-[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 222 frame #17: 0x000000010414f446 UIKit-[UIViewAnimationState animationDidStop:finished:] + 136
    frame 22103156: News app interface sometimes not visible or incorrect #18: 0x00000001096af68e QuartzCoreCA::Layer::run_animation_callbacks(void*) + 306 frame #19: 0x000000010784305c libdispatch.dylib_dispatch_client_callout + 8
    frame 22102128: Face detection accuracy is bad #20: 0x000000010782440b libdispatch.dylib_dispatch_main_queue_callback_4CF + 411 frame #21: 0x00000001069a0909 CoreFoundationCFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE + 9
    frame 22098492: Xcode-beta (7A165t): UI Tests: secureTextFields are duplicated #22: 0x0000000106966ae4 CoreFoundation__CFRunLoopRun + 2164 frame #23: 0x0000000106966016 CoreFoundationCFRunLoopRunSpecific + 406
    frame 22096010: Impossible to inspect the contents of the Core Spotlight index #24: 0x00000001087f5a24 GraphicsServicesGSEventRunModal + 62 frame #25: 0x00000001040c30d4 UIKitUIApplicationMain + 159
    frame 22094417: UIPrintInteractionController does not indicate its method of dismissal #26: 0x000000010361e1a7 WebThreadDeadLockmain at AppDelegate.swift:12 frame #27: 0x000000010788f65d libdyld.dylibstart + 1
    frame 22093439: Mac OS X 10.10.4: NSTabViewController tabStyle option NSTabViewControllerTabStyleUnspecified does not work. #28: 0x000000010788f65d libdyld.dylib`start + 1

Version:
Xcode 8.3.2, Mac OS 10.12.4

Notes:

Configuration:
iPhone 7 Simulator, iOS 10.3

Attachments:
'WebThreadDeadLock-master.zip' was successfully uploaded.
(see here: https://github.com/technology-ebay-de/WebThreadDeadLock)

Product Version: iOS 10.3
Created: 2017-05-03T03:07:09.957930
Originated: 2017-05-03T00:00:00
Open Radar Link: http://www.openradar.me/31955525