Crash in background on iOS 15 EXC_… | Apple Developer Forums

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Hello, Since the first iOS 15 beta and even with all the next public releases, we have a very weird crash each time our app enters background. The crash logs don't help at all unfortunately

Each time we see:

Exception Type:  EXC_CRASH (SIGKILL)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note:  EXC_CORPSE_NOTIFY
Triggered by Thread:  0

and

Thread 0 name:
Thread 0 Crashed:
0   libsystem_kernel.dylib        	0x00000001b7a08564 mach_msg_trap + 8
1   libsystem_kernel.dylib        	0x00000001b7a08bfc mach_msg + 76 (mach_msg.c:119)
2   CoreFoundation                	0x0000000181089698 __CFRunLoopServiceMachPort + 372 (CFRunLoop.c:2646)
3   CoreFoundation                	0x000000018108d98c __CFRunLoopRun + 1212 (CFRunLoop.c:3000)
4   CoreFoundation                	0x00000001810a13c8 CFRunLoopRunSpecific + 600 (CFRunLoop.c:3268)
5   GraphicsServices              	0x000000019c8b238c GSEventRunModal + 164 (GSEvent.c:2200)
6   UIKitCore                     	0x0000000183a47060 -[UIApplication _run] + 1100 (UIApplication.m:3457)
7   UIKitCore                     	0x00000001837c4b8c UIApplicationMain + 2124 (UIApplication.m:5013)

And sometimes we have:

Kernel Triage:
VM - Compressor failed a blocking pager_get

or

Kernel Triage:
VM - pmap_enter failed with resource shortage
VM - Compressor failed a blocking pager_get

But no other info. We can't reproduce it on simulators or on real devices with non-production release (linked to Xcode). But the crashes are here each time we build a release version.

Any help would be appreciated!

NB: it seems similar to this one but we are not even sure

2021-11-01_00-13-03.9761_+0100-a5388bfdcea65316d79dc2c3a4ac95ad146c2cb3.crash

23k

Posted by

SebC99

Reply

I found a new one with the following reason: Termination Reason: RUNNINGBOARD 3735883980 (equivalent of 0xdead10cc)

—
SebC99

Apple Recommended

Many of you in this thread have opened bug reports in Feedback Assistant — thank you for filing those to help us address this! We have deployed a fix to the backend services that provide crashes for your app into the Xcode Organizer, so if you receive EXC_CRASH (SIGKILL) crash reports from now on through the Organizer, those reports should be attributed with an exception code to explain why the system terminated your app.

If you still see any reports without the exception code, please post the complete crash report to this thread using the attachment feature so we can verify that the code is still missing.

Posted by

edford

Replies

How did you acquire this crash? A system termination (i.e. a SIGKILL initiated by the system) should have an additional reason code or description of the reason behind the termination.

Posted by

edford

Nothing more in XCode crashes

—
SebC99
On some devices we managed to download the logs and it showed a dead lock (0xdead10cc) but most of the times there’s no explanation

—
SebC99

i had a similar problem

was related to an old version of Realm

Posted by

marencod

I have a totally same crash and Kernel Triage: VM - Compressor failed a blocking pager_get

Crash Memory Stack below:

Thread 0 name: Thread 0 Crashed: 0 libsystem_kernel.dylib 0x00000001b7a08564 mach_msg_trap + 8 1 libsystem_kernel.dylib 0x00000001b7a08bfc mach_msg + 76 (mach_msg.c:119) 2 CoreFoundation 0x0000000181089698 __CFRunLoopServiceMachPort + 372 (CFRunLoop.c:2646) 3 CoreFoundation 0x000000018108d98c __CFRunLoopRun + 1212 (CFRunLoop.c:3000) 4 CoreFoundation 0x00000001810a13c8 CFRunLoopRunSpecific + 600 (CFRunLoop.c:3268) 5 GraphicsServices 0x000000019c8b238c GSEventRunModal + 164 (GSEvent.c:2200) 6 UIKitCore 0x0000000183a47060 -[UIApplication _run] + 1100 (UIApplication.m:3457) 7 UIKitCore 0x00000001837c4b8c UIApplicationMain + 2124 (UIApplication.m:5013)

More information: hardware: iPhone XR iOS version: 15.0.2 (19A404)

waiting for any resolution and hoping this could be resolved asap.

Posted by

ryotrix

Could you start a new thread, and post the complete, fully symbolicated crash log using the attachment feature? Please also detail how you received this crash log, as I requested of the original post above.

—
edford

For anyone receiving a system termination (i.e. a Exception Type: EXC_CRASH (SIGKILL)) and also seeing 0x0 in the Exception Codes line, the system should have output additional information useful for diagnosing the reason the system terminated the app, such as the exception codes 0x8badf00d, 0xdead10cc, or 0xbaadca11, as documented in Understanding the Exception Types in a Crash Report.

Please open a bug report using Feedback Assistant, as this information should never be missing from the crash report, and is crucial for identifying the source of the problem. In your bug report, please include the full Apple crash report (no reports from third-party crash reporters), as well as a description of how you received the crash report, such as through the Xcode Crashes Organizer. Once you have filed the bug report, please post the FB number here.

Posted by

edford

We are also seeing a large number of crash reports with 0x0 appeared as the Exception Codes after the release of iOS 15. See FB9775268. Thanks.

—
monomichael
Posted a report under https://feedbackassistant.apple.com/feedback/9809583

—
Nynox
I filed the bug report. (FB9972379)

—
sinoru

I also have a crash report that looks almost exactly the same. More than that, I have two more different crash reports, but all of them have zero Exception Codes and have no "Termination Reason" field.

In my case in all those crash reports I have a ton of threads that are waiting for some network operations (some Firestore stuff in my app) so my guess is that it can be related to some resource shortage (memory? descriptors? something related to threading?). But that's just a guess, I may very well be wrong.

Posted by

algrid

Could you post the FB number you filed about this info missing, per the instructions above?

—
edford

Since first iOS 15 build we've got a lot of the same crashes. We believe iOS 15 has some regressions. There are too many EXC_CRASH (SIGKILL) without any visible reason.

Posted by

Dmytro Yunchyk

Could you post the FB number you filed about this info missing, per the instructions above?

—
edford

@edford, I can confirm seeing crash reports with 0x0 exception codes on iOS 15. My guess it is the watchdog killing the app, but I'm not sure. Please see FB9791707.

Posted by

Rumio

Thank you for filing FB9791707! I looked at your crash report, and I agree that this looks like a 0x8badf00d termination, and not one of the other types. There's a descriptive main thread back trace, including a lock in the top frame, which would certainly spend time leading to a watchdog termination. Hopefully the other class names give you some clues to where to look in your app to determine how to resolve this. Please see the documentation on the watchdog for suggestions on how you can use the backtrace, even if it doesn't point directly to the source of the problem.

—
edford

@edford I am also seeing crash reports with 0x0 exception codes. I have a suspicion a thread other than main is the real culprit, but there's no evidence of that in the report. Please see FB9801972.

Posted by

IAmMichellis

Thanks for filing the bug report. Looking at the log, this seems like a 0xdead10cc termination, meaning some file locks were left open at suspension time. The evidence supporting this is that your main thread is totally idle, thus ruling out a 0x8badf00d / watchdog scenario, and Thread 1 references a third-party library that I know uses SQLite, plus class names for that thread having "Store" in the class name. We have info on 0xdead10cc in the documentation on crash Exception Codes.

—
edford

I'm also experiencing the same issue, with limited knowledge, and only in iOS 15.

Exception Type: EXC_CRASH (SIGKILL) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Triggered by Thread: 0

Kernel Triage: VM - Compressor failed a blocking pager_get

Thread 0 name: Thread 0 Crashed: 0 libsystem_kernel.dylib 0x00000001ba77b5a0 semaphore_wait_trap + 8 1 libdispatch.dylib 0x0000000183b05ee0 _dispatch_sema4_wait + 28 (lock.c:139) 2 libdispatch.dylib 0x0000000183b06598 _dispatch_semaphore_wait_slow + 132 (semaphore.c:132)

Also reported this in the Feedback Assistant: FB9803928

Posted by

x010044

Thanks!

—
eskimo
Hi Eskimo

Any news on the crash? Were you able to derive something from the added feedback?

Best

—
x010044

@edford please take a look at my report https://feedbackassistant.apple.com/feedback/9809233

Look like something is wrong with App Group.

Posted by

haisk

How did you get this crash report — was it through the Xcode Organizer, or some other source? Your crash report has the reason for the issue in it, and I'd like to keep this thread focused on crashes that are missing the reason. I suggest you open a new forums thread or Technical Support Incident with the crash report, and we can go over the details that way.

—
edford
I got it from Windows -> Devices and Simulators. But I also got many crashes of that type from Organizer too, all on iOS 15.

—
haisk

@edford please take a look at my report https://feedbackassistant.apple.com/feedback/9816327 I get these crash logs from Xcode organizer. All of them have no crash reason and organizer shows NO_CRASH_STACK + 0 for them.

Posted by

lei

I also posted a new thread https://developer.apple.com/forums/thread/697044#697044021

—
lei
@lei, I responded over in your other forums thread.

—
edford
@edford Thank you so much!

—
lei

hi @edford, I'm having a similar issue. Filed a report here https://feedbackassistant.apple.com/feedback/9823992. Thanks

Posted by

PostChris

@PostChris, I'd catalog your crash reports as most likely being 0x8badf00d watchdog terminations, though that's a best guess and not a certainty given the missing info — thank you for filing the feedback report so we can address the missing info. In each of these, you're deep inside UIKit and layout code. In some, you were just launched, but in others, the app was alive for a very long time, indicating a scene update that took too long, which also can trigger the watchdog. Focus your debugging on ensuring your launch time and app restoration time from a suspended state are fast.

—
edford
Hi @edford, thanks for getting back to me. I did also notice one crash log unrelated to UIKit - I've attached it to the feedback ticket.

—
PostChris

I’m also seen SIGKILL crashes with 0x0 exception codes and no termination reason. In this case, looking at the backtraces, it seems that it is originated from core data / cloudkit.

https://feedbackassistant.apple.com/feedback/9825704

Thanks!

Posted by

Alex_Garcia_87

Hi @edford, Please also see https://feedbackassistant.apple.com/feedback/9826162, we are seeing numerous SIGKILL crashes with 0x0 exception codes and no termination reason on iOS15.

—
ptclarke
@Alex_Garcia_87, thank you for the feedback report. Looking at the log, this seems like a 0xdead10cc termination, meaning some file locks were left open at suspension time. The evidence supporting this is that your main thread is totally idle, thus ruling out a 0x8badf00d / watchdog scenario, plus you have background threads touching SQLlite. We have info on 0xdead10cc in the documentation on crash Exception Codes.

—
edford
@ptclarke, looking at your reports in 9826162, you are encountering a termination for the watchdog, i.e. exception code 0x8badf00d. Consider that your main thread is always waiting on a lock as part of servicing an operation group, and servicing those operations is taking too long and thus encountering the watchdog.

—
edford

Hello edford,

As advised I've submitted a bug report here with the details you requested: https://feedbackassistant.apple.com/feedback/9831706

In my case, I have 5 crashes which are all Exception Type: EXC_CRASH (SIGKILL), and with missing "Termination Reason".

The Kernel Triage: sections include variations on the following:

VM - Compressor failed a blocking pager_get
VM - Fault hit memory shortage

Posted by

chojubo

@chojubo, thank you for the feedback report. They look like 0x8badf00d terminations, in that you are deep inside layout code as a result of the system taking a snapshot of your UI. Focus on making sure your UI can layout and update quickly.

—
edford

Hi adford,

I submitted my Feedback too. crash signature are same as above:

https://feedbackassistant.apple.com/feedback/9833627

VM - Fault hit memory shortage
VM - Compressor failed a blocking pager_get

Posted by

Jeff Lu

@Jeff+Lu, These crashes are not the same as what's being discussed in the rest of the thread. These are EXC_CRASH (SIGABRT), indicating that abort was called, and not EXC_CRASH (SIGKILL), which is about system-initiated terminations for specific policies, like system responsiveness. abort was called here due to an uncaught exception via -[PKPushRegistry _terminateAppIfThereAreUnhandledVoIPPushes]. If you need help addressing this further, please open a Technical Support Incident.

—
edford