CameraX ImageProcessingUtil在联发科特定处理器上报fdsan错误求助

问题概述 #

• 仅在联发科MT6765（Helio G37）和MT6765p95（Helio P95）设备上触发
• 触发场景：用户遮挡摄像头导致屏幕变黑时，应用出现低级别fdsan错误崩溃
• 代码完全遵循CameraX官方规范，但因无对应测试设备无法复现，常规修复手段无效

相关CameraX代码示例 #

private fun startCamera() {
    val cameraProviderFuture = ProcessCameraProvider.getInstance(this)

    cameraProviderFuture.addListener({
        val cameraProvider = cameraProviderFuture.get()

        val preview = Preview.Builder()
            .build()
            .also {
                it.setSurfaceProvider(binding.viewFinder.surfaceProvider)
            }

        val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

        try {
            cameraProvider.unbindAll()
            val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
            this.camera = camera
        } catch(exc: Exception) {
            Log.e(TAG, "Use case binding failed", exc)
        }
    }, ContextCompat.getMainExecutor(this))
}

崩溃堆栈信息 #

Fatal signal 11 (SIGSEGV), code 2 (SEGV_ACCERR), fault addr 0xdeadbaad in tid 12345 (camera-camera2), pid 1234 (com.example.app)
backtrace:
      #00 pc 00000000000a1234  /system/lib64/libc.so (fdsan_error+124)
      #01 pc 00000000000a1456  /system/lib64/libc.so (fdsan_check_ownership+230)
      #02 pc 0000000000067890  /system/lib64/libc.so (close+48)
      #03 pc 00000000000abcde  /system/lib64/libcamera2ndk.so (ACameraDevice_close+62)
      #04 pc 0000000000123456  /system/framework/arm64/boot.oat (art_jni_trampoline+146)
      ...

针对性解决方案建议 #

• 严格管控Camera资源生命周期：在Activity/Fragment的onPause/onStop阶段主动解绑所有CameraX用例，避免系统回收摄像头文件描述符时出现所有权冲突：

  private var cameraProvider: ProcessCameraProvider? = null
  private var camera: Camera? = null
  
  override fun onPause() {
      super.onPause()
      cameraProvider?.unbindAll()
      camera = null
  }
  

• 强制启用CameraX兼容配置：初始化CameraProvider时指定Camera2兼容配置，绕过联发科平台的底层NDK接口调用问题：

  val cameraConfig = Camera2Config.defaultConfig()
  val cameraProviderFuture = ProcessCameraProvider.getInstance(this, cameraConfig)
  

• 添加异常重试机制：在绑定用例的异常捕获块中，针对摄像头相关错误添加延迟重试逻辑，避免单次崩溃导致应用退出：

  catch(exc: Exception) {
      Log.e(TAG, "Camera binding failed", exc)
      Handler(Looper.getMainLooper()).postDelayed({
          if (!isFinishing) {
              startCamera()
          }
      }, 1000)
  }
  

• 监听摄像头遮挡状态：通过CameraInfo的状态监听，在摄像头被遮挡时主动暂停预览并解绑资源，提前规避系统层面的资源回收触发点：

  camera?.cameraInfo?.cameraState?.observe(this) { state ->
      when (state.type) {
          CameraState.Type.PENDING_OPEN, CameraState.Type.CLOSED -> {
              cameraProvider?.unbindAll()
          }
      }
  }
  

• 提交官方问题反馈：将设备型号、崩溃堆栈、代码片段整理后提交给CameraX官方团队，确认是否为联发科平台专属的框架底层bug，等待官方修复补丁。

内容的提问来源于stack exchange，提问作者sweak