diff --git a/services/sensorservice/SensorService.cpp b/services/sensorservice/SensorService.cpp
index c7bcaeff2..a401145c0 100644
--- a/services/sensorservice/SensorService.cpp
+++ b/services/sensorservice/SensorService.cpp
@@ -1709,7 +1709,7 @@ int SensorService::SensorEventConnection::handleEvent(int fd, int events, void*
 #endif
            } else if (numBytesRead == sizeof(uint32_t)) {
                uint32_t numAcks = 0;
-               memcpy(&numAcks, buf, sizeof(numBytesRead));
+               memcpy(&numAcks, buf, numBytesRead);
                // Sanity check to ensure  there are no read errors in recv, numAcks is always
                // within the range and not zero. If any of the above don't hold reset
                // mWakeLockRefCount to zero.