Crash in libcamera2ndk.so (SIGSEGV) in versions prior to Android 8.1 / Android O MR1 (API 27)

[RegisAG]

I have an app in production used by many users. On some of them, only on Android 7.x, I have got the following error:

*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
pid: 0, tid: 0

backtrace:
  #00  pc 000000000000b91c  /system/lib64/libcamera2ndk.so
  #01  pc 000000000000d0a0  /system/lib64/libcamera2ndk.so
  #02  pc 000000000001499c  /system/lib64/libcamera2ndk.so
  #03  pc 00000000000166bc  /system/lib64/libcamera2ndk.so
  #04  pc 00000000000120f4  /system/lib64/libstagefright_foundation.so (_ZN7android8AHandler14deliverMessageERKNS_2spINS_8AMessageEEE+52)
  #05  pc 0000000000015e9c  /system/lib64/libstagefright_foundation.so (_ZN7android8AMessage7deliverEv+112)
  #06  pc 000000000001322c  /system/lib64/libstagefright_foundation.so (_ZN7android7ALooper4loopEv+480)
  #07  pc 00000000000124e8  /system/lib64/libutils.so (_ZN7android6Thread11_threadLoopEPv+272)
  #08  pc 00000000000a5110  /system/lib64/libandroid_runtime.so (_ZN7android14AndroidRuntime15javaThreadShellEPv+116)
  #09  pc 00000000000696bc  /system/lib64/libc.so (_ZL15__pthread_startPv+196)
  #10  pc 000000000001dbf0  /system/lib64/libc.so (__start_thread+16)

Any idea on the origin of this problem ?

[inio]

This, unfortunately, is a known issue in Android versions prior to 8.1. It generally occurs only during extremely high CPU usage. There's nothing we can do about it. ☹️

[RegisAG]

Any update concerning this problem ? Note that according to my Android Vitals dashboard, this crash happens almost only on: Galaxy S7 Edge (hero2lte) (47.3% of the crashes), Galaxy S7 (herolte) (42% of the crashes), Galaxy S7 (heroltebmc) (2.2% of the crashes) => 90% of the occurences of this crash happen on S7 (running Android 7.x). Do you plan to fix this problem ? The S7 represents 20% of my installs and thus crash has a bad influence on my rating.

[inio]

This issue happens with high CPU load resulting in blocked Binder threads. If you can reduce your app's CPU usage and avoid blocking/waiting in any callbacks running on Binder threads, it may reduce this issue.

Long term, we're looking at ways to mitigate this issue, but they are major rewrites of substantial parts of our codebase. This is a bug in the android NDK Camera 2 API implementation that was fixed in Android 8.1.

[RegisAG]

"avoid blocking/waiting in any callbacks running on Binder threads" : how to do that ? :)

[inio]

Anything related to Android services should avoid blocking in callbacks. Google Play Services for example.

[gkiernozek]

@RegisAG - try newest ARCore 1.9.0 - I have not experienced the freeze yet from time I've updated SDK and hopefully it stays this way :)

Let me know if 1.9.0 ever crashes for you as it did in previous versions so I can be prepared that problem can still occur.

[Noltibus]

We still experience this error in production. Only on Samsung devices (S8, A6, A7 2108) with Android versions 9 and 10. the stacktrace reads as follows:

signal 11 (SIGSEGV), code 1 (SEGV_MAPERR)
*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
pid: 0, tid: 0 >>> one.realnote.app <<<

backtrace:
  #00  pc 000000000001e1b0  /system/lib64/libcamera2ndk.so (android::acam::CameraManagerGlobal::DeathNotifier::binderDied(android::wp<android::IBinder> const&)+276)
  #01  pc 000000000004e400  /system/lib64/libbinder.so (android::BpBinder::reportOneDeath(android::BpBinder::Obituary const&)+148)
  #02  pc 000000000004e320  /system/lib64/libbinder.so (android::BpBinder::sendObituary()+148)
  #03  pc 0000000000058b18  /system/lib64/libbinder.so (android::IPCThreadState::executeCommand(int)+668)
  #04  pc 00000000000587c8  /system/lib64/libbinder.so (android::IPCThreadState::getAndExecuteCommand()+156)
  #05  pc 0000000000058f04  /system/lib64/libbinder.so (android::IPCThreadState::joinThreadPool(bool)+60)
  #06  pc 000000000007f024  /system/lib64/libbinder.so (android::PoolThread::threadLoop()+24)
  #07  pc 00000000000135fc  /system/lib64/libutils.so (android::Thread::_threadLoop(void*)+288)
  #08  pc 00000000000ef900  /system/lib64/libandroid_runtime.so (android::AndroidRuntime::javaThreadShell(void*)+140)
  #09  pc 00000000000e28c0  /apex/com.android.runtime/lib64/bionic/libc.so (__pthread_start(void*)+36)
  #10  pc 000000000008503c  /apex/com.android.runtime/lib64/bionic/libc.so (__start_thread+64)

Currently using ArCore 1.16