Bug 251092 – Webview crashes (sometimes) when modals (windows) are loading in the background

• Component: WebKit Misc.
• Status: NEW

[PaulPlay]

I am using cordova with the Construct 3 game engine and when switching to a different window which is preloaded I experience this webkit-realted bug.

Xcode debug console error:
2023-01-24 17:15:35.778534+0100 Bluelife[25718:8527896] [ServicesDaemonManager] interruptionHandler is called. -[FontServicesDaemonManager connection]_block_invoke
2023-01-24 17:17:16.160571+0100 Bluelife[25718:8529054] [XPC] Handle connection with error: Connection interrupted
2023-01-24 17:19:07.020278+0100 Bluelife[25718:8522619] [Process] 0x10d003c60 - [PID=25721] WebProcessProxy::didClose: (web process 25721 crash)
2023-01-24 17:19:07.021206+0100 Bluelife[25718:8522619] [Process] 0x10d003c60 - [PID=25721] WebProcessProxy::processDidTerminateOrFailedToLaunch: reason=Crash
2023-01-24 17:19:07.021411+0100 Bluelife[25718:8522619] [ProcessSuspension] 0x10c01c120 - ProcessAssertion: Failed to acquire RBS Background assertion 'ConnectionTerminationWatchdog' for process because PID 0 is invalid
2023-01-24 17:19:07.022371+0100 Bluelife[25718:8522619] [Process] 0x13a039218 - [pageProxyID=14, webPageID=15, PID=25721] WebPageProxy::processDidTerminate: (pid 25721), reason=Crash
2023-01-24 17:19:07.022481+0100 Bluelife[25718:8530140] [ProcessSuspension] 0x10c01c120 - ProcessAssertion::acquireSync Failed to acquire RBS assertion 'ConnectionTerminationWatchdog' for process with PID=0, error: (null)
2023-01-24 17:19:07.042997+0100 Bluelife[25718:8530140] [assertion] Error acquiring assertion: <Error Domain=RBSServiceErrorDomain Code=1 "target is not running or doesn't have entitlement com.apple.runningboard.assertions.webkit" UserInfo={NSLocalizedFailureReason=target is not running or doesn't have entitlement com.apple.runningboard.assertions.webkit}>
2023-01-24 17:19:07.043389+0100 Bluelife[25718:8530140] [ProcessSuspension] 0x10c01c180 - ProcessAssertion::acquireSync Failed to acquire RBS assertion 'WebProcess Background Assertion' for process with PID=25721, error: Error Domain=RBSServiceErrorDomain Code=1 "target is not running or doesn't have entitlement com.apple.runningboard.assertions.webkit" UserInfo={NSLocalizedFailureReason=target is not running or doesn't have entitlement com.apple.runningboard.assertions.webkit}
2023-01-24 17:19:07.085655+0100 Bluelife[25718:8522619] [Loading] 0x13a039218 - [pageProxyID=14, webPageID=15, PID=25721] WebPageProxy::dispatchProcessDidTerminate: reason=Crash
2023-01-24 17:19:07.162310+0100 Bluelife[25718:8522619] [Process] 0x10c0744e0 - GPUProcessProxy::gpuProcessExited: reason=IdleExit
2023-01-24 17:19:07.162426+0100 Bluelife[25718:8522619] [Process] 0x10d001510 - [PID=0] WebProcessProxy::gpuProcessExited: reason=IdleExit
2023-01-24 17:19:07.165540+0100 Bluelife[25718:8522619] [Sandbox] Could not enable Mach bootstrap, errno = 1.
2023-01-24 17:19:07.165725+0100 Bluelife[25718:8522619] [Sandbox] Could not enable Mach bootstrap, errno = 1.
2023-01-24 17:19:07.719692+0100 Bluelife[25718:8522619] IAB.close() called but it was already closed.






Device crashlog:


Date/Time: 2023-01-24 17:05:47.942 +0100
End time: 2023-01-24 17:10:19.709 +0100
OS Version: iPhone OS 16.2 (Build 20C65)
Architecture: arm64e
Report Version: 40
Incident Identifier: 809899E9-41F5-4260-9C3A-F43C4389CB35

Data Source: Microstackshots
Shared Cache: D962ECAE-C2C7-30CA-A3A4-779B8ECD896A slid base address 0x185d9c000, slide 0x5d9c000
Shared Cache: E3B4ED03-39A9-349E-B41F-0C9156CC6150 slid base address 0x1dc27c000, slide 0x5c27c000

Command: com.apple.WebKit.Networking
Path: /private/preboot/Cryptexes/OS/System/Library/Frameworks/WebKit.framework/XPCServices/com.apple.WebKit.Networking.xpc/com.apple.WebKit.Networking
Identifier: com.apple.WebKit.Networking
Version: 8614 (8614.3.7.0.6)
Resource Coalition ID: 2367
Architecture: arm64
PID: 25722

Event: wakeups
Action taken: none
Wakeups: 45001 wakeups over the last 272 seconds (166 wakeups per second average), exceeding limit of 150 wakeups per second over 300 seconds
Wakeups limit: 45000
Limit duration: 300s
Wakeups caused: 45001
Wakeups duration: 272s
Duration: 271.77s
Duration Sampled: 265.75s
Steps: 135

Hardware model: iPhone12,3
Active cpus: 6
HW page size: 16384
VM page size: 16384

OS Cryptex File Extents: 3756

Heaviest stack for the target process:
2 ??? (libsystem_pthread.dylib + 2968) [0x1dac1db98]
2 ??? (libsystem_pthread.dylib + 3576) [0x1dac1ddf8]
2 ??? (libdispatch.dylib + 93712) [0x1941bbe10]
1 ??? (libdispatch.dylib + 49376) [0x1941b10e0]

Powerstats for: com.apple.WebKit.Networking [25722] [unique pid 225368]
UUID: 1FD526B8-4C03-36F3-A4D5-46B7C61B6B9D
Path: /private/preboot/Cryptexes/OS/System/Library/Frameworks/WebKit.framework/XPCServices/com.apple.WebKit.Networking.xpc/com.apple.WebKit.Networking
Identifier: com.apple.WebKit.Networking
Version: 8614 (8614.3.7.0.6)
Shared Cache: D962ECAE-C2C7-30CA-A3A4-779B8ECD896A slid base address 0x185d9c000, slide 0x5d9c000
Resource Coalition ID: 2367
Architecture: arm64
Footprint: 4272 KB -> 5248 KB (+976 KB)
Pageins: 63 pages
Start time: 2023-01-24 17:06:04.165 +0100
End time: 2023-01-24 17:10:13.894 +0100
Num samples: 6 (4%)
Primary state: 2 samples Frontmost App, Non-Suppressed, User mode, Effective Thread QoS User Initiated, Requested Thread QoS User Initiated, Override Thread QoS Unspecified
User Activity: 0 samples Idle, 6 samples Active
Power Source: 0 samples on Battery, 6 samples on AC

[Alexey Proskuryakov]

This is not a crash, just a logging for significant work being done in the background.

Not entirely sure what the purpose of that is, but probably no reason to be concerned.

[PaulPlay]

Interesting. However, the app then goes black and reloads the entire webview. I monitored ram / cpu / gpu usage in xcode and also looked for memory leaks but found nothing that could have caused this. A few other cordova users experience this issue (https://github.com/apache/cordova-ios/issues/1103). It could be connected to this issue: https://github.com/ionic-team/ionic-framework/issues/25760.

[PaulPlay]

This might also be the same webview problem: https://developer.apple.com/forums/thread/709919

[Alexey Proskuryakov]

> However, the app then goes black and reloads the entire webview.

Fair enough. Can you provide detailed steps to reproduce please? Generally, we wouldn't be able to follow sets that include making our own test project.

[PaulPlay]

Alright, I‘ll try to create an xcode project where I can reproduce the bug. Unfortunately, it‘s only crashing around 5% of the time, that makes it hard to check whether a change really led to the crash.

[Radar WebKit Bug Importer]

<rdar://problem/104870666>

[PaulPlay]

So I‘ve tried a lot to replicate this bug, but it does not occur in the simulator wich makes it extremely tough to test. It happened in places where it had never happened once, often with a very low probability. I only know that it is connected to switching windows and loading images into memory, but really that is it. The size of the images doesn’t matter that much, but you need a big amount of them (>100). I was able to replicate it once (out of ~80 tries) in a test project but it didn’t occur a single time in it since. In my main project however, which is a lot bigger in scale, it happens more often (still rather rare).