[Crashlytics] ANR on main thread due to awaitEvenIfOnMainThread when third-party SDKs are present in the UncaughtExceptionHandler chain

[AntonMishanin]

Environment:

• Firebase Component: firebase-crashlytics
• Component version: com.google.firebase:firebase-crashlytics:20.0.4
• Android versions: 100% android 11
• Devices: 80% Samsung, Xiaomi, Oppo
• Device state: 100% background

The project includes HMS push notifications, location. But we don't use hms crashlytics or hms analytics.

Describe the problem

We're seeing ANRs on the main thread that occur during crash handling. The stack trace consistently points to Crashlytics waiting inside awaitEvenIfOnMainThread:

   main (timed waiting):tid=1 systid=12425 
       at sun.misc.Unsafe.park(Native method)
       at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:230)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedNanos(AbstractQueuedSynchronizer.java:1063)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer.tryAcquireSharedNanos(AbstractQueuedSynchronizer.java:1358)
       at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:278)
       at com.google.firebase.crashlytics.internal.common.Utils.awaitEvenIfOnMainThread(Utils.java:62)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsController.handleUncaughtException(CrashlyticsController.java:262)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsController.handleUncaughtException(CrashlyticsController.java:181)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsController$1.onUncaughtException(CrashlyticsController.java:168)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsUncaughtExceptionHandler.uncaughtException(CrashlyticsUncaughtExceptionHandler.java:54)
       at com.huawei.hms.network.embedded.t4.uncaughtException(:141)
       at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:1073)
       at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:1068)
       at java.lang.Thread.dispatchUncaughtException(Thread.java:2203)

Also I can see com.huawei.hms.network.embedded.t4.uncaughtException

Steps to reproduce:

Unknown

Question

1. Now awaitEvenIfOnMainThread is @deprecated. What are your plans about this function?
2. Could this function affect ANR?

[lehcar09]

Hi @AntonMishanin, thank you for reaching out. I tried reproducing the issue, but, I wasn't able to encounter the ANR issue.

Upon further checking, it's possible that this was missed during the migration of handling the background tasks (PR #6267). Let me raise this to our engineers and get back to you.

Could this function affect ANR?

I'd say YES, there are similar reports (i.e. #4345) before and has been fixed in Crashlytics version 19.2.0