diff --git a/hal/mbed_critical_section_api.c b/hal/mbed_critical_section_api.c
index 05b42b6f8fa..d9bbc7bc3be 100644
--- a/hal/mbed_critical_section_api.c
+++ b/hal/mbed_critical_section_api.c
@@ -21,8 +21,8 @@
 
 #include <stdbool.h>
 
-static volatile bool critical_interrupts_enabled = false;
-static volatile bool state_saved = false;
+static bool critical_interrupts_enabled = false;
+static bool state_saved = false;
 
 static bool are_interrupts_enabled(void)
 {
diff --git a/platform/mbed_critical.c b/platform/mbed_critical.c
index 320319ba637..b146684c29e 100644
--- a/platform/mbed_critical.c
+++ b/platform/mbed_critical.c
@@ -43,7 +43,7 @@
 #endif
 #endif
 
-static volatile uint32_t critical_section_reentrancy_counter = 0;
+static uint32_t critical_section_reentrancy_counter = 0;
 
 bool core_util_are_interrupts_enabled(void)
 {
@@ -77,11 +77,11 @@ bool core_util_in_critical_section(void)
 
 void core_util_critical_section_enter(void)
 {
+    hal_critical_section_enter();
+
     // If the reentrancy counter overflows something has gone badly wrong.
     MBED_ASSERT(critical_section_reentrancy_counter < UINT32_MAX);
 
-    hal_critical_section_enter();
-
     ++critical_section_reentrancy_counter;
 }