How to fix Android NDK app crash with UnsatisfiedLinkError when loading protobuf-lite.so on Android 6.0?

Issue

I have created an Android application with a custom C++ library that depends on Google's protobuf-lite library. It works fine on all the recent devices I have tried to run it on (under Android 7, 8 and 8.1). However, I found that on older devices running Android 6.0.1 or 6.0 (Asus Nexus 7 and some old Motorola phone), the application crashes on loading the libprotobuf-lite.so dependency.

Here is the stacktrace I get:

E/AndroidRuntime: FATAL EXCEPTION:
main Process: com.mycompany.core, PID: 11582 java.lang.UnsatisfiedLinkError:
dlopen failed: cannot locate symbol "__aeabi_memmove8" referenced by "/data/app/com.mycompany.core-2/lib/arm/libprotobuf-lite.so"...
at java.lang.Runtime.loadLibrary(Runtime.java:372)
at java.lang.System.loadLibrary(System.java:1076)
at com.mycompany.core.CameraTestActivity.<clinit>(CameraTestActivity.java:46)
at java.lang.Class.newInstance(Native Method)
at android.app.Instrumentation.newActivity(Instrumentation.java:1067)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2317)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)$
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

This is really weird because the missing symbol "__aeabi_memmove8" appears to be a low-level standard library feature and I do not really grasp why it would not be found on Android 6.

In addition, I am quite confident that the issue comes from protobuf-lite not linking correctly because previous versions of my app, which were not using protobuf, ran fine on these Android 6 devices.

Below are some details on my config.

• Protobuf version: 3.6.1
• Lib package cross-compiled from source using Cmake GUI, NDK r18 toolchain and MinGW
• Devices' ABI: armeabi-v7a
• Android SDK compile version: API 28
• Application build toolchain : Gradle + CMake.
• Android Studio 3.1.3

Here is my build.gradle file:

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.mycompany.core"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cppFlags "-frtti -fexceptions"
            }
        }
    }
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

            ndk{
                abiFilters "arm64-v8a", "armeabi-v7a"
            }
        }

        debug {
            ndk{
                abiFilters "arm64-v8a", "armeabi-v7a"
            }
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}
dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation "android.arch.lifecycle:extensions:1.1.0"
    implementation "android.arch.lifecycle:viewmodel:1.1.0"
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

And here is my CMakeLists.txt file:

cmake_minimum_required(VERSION 3.4.1)

include_directories(src/main/cpp/protobuf/include)

file(GLOB SRCS
    "src/main/cpp/core/*.cpp"
    )

file(GLOB JNI_SRCS
        "src/main/cpp/jni/*.cpp"
        )

add_library(mycorelib SHARED ${SRCS} ${JNI_SRCS})

find_library(log-lib log)

add_library(libprotobuf-lite SHARED IMPORTED)

set_target_properties(libprotobuf-lite
                    PROPERTIES IMPORTED_LOCATION
                    ${CMAKE_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libprotobuf-lite.so)

target_link_libraries(mycorelib
                        android
                        jnigraphics
                        ${log-lib}
                        libprotobuf-lite)

Has anyone run into this problem before? Any hint on how to fix this would be greatly appreciated.

Solution

This is https://android.googlesource.com/platform/ndk/+/master/docs/user/common_problems.md#cannot-locate-symbols.

Your protobuf library was built for a higher minSdkVersion than the rest of your app, and cannot run on the device you're using.

Answered By - Dan Albert