diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index 07614b4..d7146ae 100644
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -235,7 +235,7 @@
 {
   ASSERT (bytes <= svm_fifo_max_enqueue (f));
   f->tail = (f->tail + bytes) % f->nitems;
-  f->cursize += bytes;
+  clib_atomic_fetch_add_rel (&f->cursize, bytes);
 }
 
 always_inline u8 *