diff --git a/src/fiber/context/aarch64-generic.cr b/src/fiber/context/aarch64-generic.cr
index 2839ee030ef5..110a8b77aa88 100644
--- a/src/fiber/context/aarch64-generic.cr
+++ b/src/fiber/context/aarch64-generic.cr
@@ -54,6 +54,9 @@ class Fiber
 
       mov     x19, sp               // current_context.stack_top = sp
       str     x19, [x0, #0]
+      {% if flag?(:execution_context) %}
+      dmb     ish                   // barrier: ensure registers are stored
+      {% end %}
       mov     x19, #1               // current_context.resumable = 1
       str     x19, [x0, #8]
 
@@ -97,6 +100,9 @@ class Fiber
 
       mov     x19, sp               // current_context.stack_top = sp
       str     x19, [$0, #0]
+      {% if flag?(:execution_context) %}
+      dmb     ish                   // barrier: ensure registers are stored
+      {% end %}
       mov     x19, #1               // current_context.resumable = 1
       str     x19, [$0, #8]
 
diff --git a/src/fiber/context/aarch64-microsoft.cr b/src/fiber/context/aarch64-microsoft.cr
index b9e86dfbc6cf..2d94a64dd36c 100644
--- a/src/fiber/context/aarch64-microsoft.cr
+++ b/src/fiber/context/aarch64-microsoft.cr
@@ -55,6 +55,9 @@ class Fiber
 
       mov     x19, sp               // current_context.stack_top = sp
       str     x19, [x0, #0]
+      {% if flag?(:execution_context) %}
+      dmb     ish                   // barrier: ensure registers are stored
+      {% end %}
       mov     x19, #1               // current_context.resumable = 1
       str     x19, [x0, #8]
 
@@ -112,6 +115,9 @@ class Fiber
 
       mov     x19, sp               // current_context.stack_top = sp
       str     x19, [$0, #0]
+      {% if flag?(:execution_context) %}
+      dmb     ish                   // barrier: ensure registers are stored
+      {% end %}
       mov     x19, #1               // current_context.resumable = 1
       str     x19, [$0, #8]