diff --git a/qemu/cpu-exec.c b/qemu/cpu-exec.c
index 50df1414..731e9549 100644
--- a/qemu/cpu-exec.c
+++ b/qemu/cpu-exec.c
@@ -405,11 +405,11 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
          * have set something else (eg exit_request or
          * interrupt_request) which we will handle
          * next time around the loop.  But we need to
-         * ensure the tcg_exit_req read in generated code
+         * ensure the zeroing of tcg_exit_req (see cpu_tb_exec)
          * comes before the next read of cpu->exit_request
          * or cpu->interrupt_request.
          */
-        smp_rmb();
+        smp_mb();
         *last_tb = NULL;
         break;
     case TB_EXIT_ICOUNT_EXPIRED: