diff --git a/libs/rs/rsLocklessFifo.cpp b/libs/rs/rsLocklessFifo.cpp
index 3f88543..70b7278 100644
--- a/libs/rs/rsLocklessFifo.cpp
+++ b/libs/rs/rsLocklessFifo.cpp
@@ -100,7 +100,9 @@
     //dumpState("commit 1");
     reinterpret_cast<uint16_t *>(mPut)[0] = command;
     reinterpret_cast<uint16_t *>(mPut)[1] = sizeInBytes;
-    mPut += ((sizeInBytes + 3) & ~3) + 4;
+
+    int32_t s = ((sizeInBytes + 3) & ~3) + 4;
+    android_atomic_add(s, (int32_t *)&mPut);
     //dumpState("commit 2");
     mSignalToWorker.set();
 }