diff --git a/gc.c b/gc.c
index 0ee444e026..4bd9641cb6 100644
--- a/gc.c
+++ b/gc.c
@@ -1239,99 +1239,102 @@ RVALUE_FLAGS_AGE(VALUE flags)
 static int
 check_rvalue_consistency_force(const VALUE obj, int terminate)
 {
-    rb_objspace_t *objspace = &rb_objspace;
     int err = 0;
+    rb_objspace_t *objspace = &rb_objspace;
 
-    if (SPECIAL_CONST_P(obj)) {
-        fprintf(stderr, "check_rvalue_consistency: %p is a special const.\n", (void *)obj);
-        err++;
-    }
-    else if (!is_pointer_to_heap(objspace, (void *)obj)) {
-        /* check if it is in tomb_pages */
-        struct heap_page *page = NULL;
-        list_for_each(&heap_tomb->pages, page, page_node) {
-            if (&page->start[0] <= (RVALUE *)obj &&
-                (RVALUE *)obj < &page->start[page->total_slots]) {
-                fprintf(stderr, "check_rvalue_consistency: %p is in a tomb_heap (%p).\n",
-                        (void *)obj, (void *)page);
-                err++;
-                goto skip;
+    RB_VM_LOCK_ENTER_NO_BARRIER();
+    {
+        if (SPECIAL_CONST_P(obj)) {
+            fprintf(stderr, "check_rvalue_consistency: %p is a special const.\n", (void *)obj);
+            err++;
+        }
+        else if (!is_pointer_to_heap(objspace, (void *)obj)) {
+            /* check if it is in tomb_pages */
+            struct heap_page *page = NULL;
+            list_for_each(&heap_tomb->pages, page, page_node) {
+                if (&page->start[0] <= (RVALUE *)obj &&
+                    (RVALUE *)obj < &page->start[page->total_slots]) {
+                    fprintf(stderr, "check_rvalue_consistency: %p is in a tomb_heap (%p).\n",
+                            (void *)obj, (void *)page);
+                    err++;
+                    goto skip;
+                }
             }
-        }
-        bp();
-        fprintf(stderr, "check_rvalue_consistency: %p is not a Ruby object.\n", (void *)obj);
-        err++;
-      skip:
-        ;
-    }
-    else {
-        const int wb_unprotected_bit = RVALUE_WB_UNPROTECTED_BITMAP(obj) != 0;
-        const int uncollectible_bit = RVALUE_UNCOLLECTIBLE_BITMAP(obj) != 0;
-        const int mark_bit = RVALUE_MARK_BITMAP(obj) != 0;
-        const int marking_bit = RVALUE_MARKING_BITMAP(obj) != 0, remembered_bit = marking_bit;
-        const int age = RVALUE_FLAGS_AGE(RBASIC(obj)->flags);
-
-        if (GET_HEAP_PAGE(obj)->flags.in_tomb) {
-            fprintf(stderr, "check_rvalue_consistency: %s is in tomb page.\n", obj_info(obj));
-            err++;
-        }
-        if (BUILTIN_TYPE(obj) == T_NONE) {
-            fprintf(stderr, "check_rvalue_consistency: %s is T_NONE.\n", obj_info(obj));
-            err++;
-        }
-        if (BUILTIN_TYPE(obj) == T_ZOMBIE) {
-            fprintf(stderr, "check_rvalue_consistency: %s is T_ZOMBIE.\n", obj_info(obj));
+            bp();
+            fprintf(stderr, "check_rvalue_consistency: %p is not a Ruby object.\n", (void *)obj);
             err++;
+          skip:
+            ;
         }
+        else {
+            const int wb_unprotected_bit = RVALUE_WB_UNPROTECTED_BITMAP(obj) != 0;
+            const int uncollectible_bit = RVALUE_UNCOLLECTIBLE_BITMAP(obj) != 0;
+            const int mark_bit = RVALUE_MARK_BITMAP(obj) != 0;
+            const int marking_bit = RVALUE_MARKING_BITMAP(obj) != 0, remembered_bit = marking_bit;
+            const int age = RVALUE_FLAGS_AGE(RBASIC(obj)->flags);
 
-        obj_memsize_of((VALUE)obj, FALSE);
-
-        /* check generation
-         *
-         * OLD == age == 3 && old-bitmap && mark-bit (except incremental marking)
-         */
-        if (age > 0 && wb_unprotected_bit) {
-            fprintf(stderr, "check_rvalue_consistency: %s is not WB protected, but age is %d > 0.\n", obj_info(obj), age);
-            err++;
-        }
-
-        if (!is_marking(objspace) && uncollectible_bit && !mark_bit) {
-            fprintf(stderr, "check_rvalue_consistency: %s is uncollectible, but is not marked while !gc.\n", obj_info(obj));
-            err++;
-        }
-
-        if (!is_full_marking(objspace)) {
-            if (uncollectible_bit && age != RVALUE_OLD_AGE && !wb_unprotected_bit) {
-                fprintf(stderr, "check_rvalue_consistency: %s is uncollectible, but not old (age: %d) and not WB unprotected.\n",
-                        obj_info(obj), age);
+            if (GET_HEAP_PAGE(obj)->flags.in_tomb) {
+                fprintf(stderr, "check_rvalue_consistency: %s is in tomb page.\n", obj_info(obj));
                 err++;
             }
-            if (remembered_bit && age != RVALUE_OLD_AGE) {
-                fprintf(stderr, "check_rvalue_consistency: %s is remembered, but not old (age: %d).\n",
-                        obj_info(obj), age);
+            if (BUILTIN_TYPE(obj) == T_NONE) {
+                fprintf(stderr, "check_rvalue_consistency: %s is T_NONE.\n", obj_info(obj));
                 err++;
             }
-        }
-
-        /*
-         * check coloring
-         *
-         *               marking:false marking:true
-         * marked:false  white         *invalid*
-         * marked:true   black         grey
-         */
-        if (is_incremental_marking(objspace) && marking_bit) {
-            if (!is_marking(objspace) && !mark_bit) {
-                fprintf(stderr, "check_rvalue_consistency: %s is marking, but not marked.\n", obj_info(obj));
+            if (BUILTIN_TYPE(obj) == T_ZOMBIE) {
+                fprintf(stderr, "check_rvalue_consistency: %s is T_ZOMBIE.\n", obj_info(obj));
                 err++;
             }
+
+            obj_memsize_of((VALUE)obj, FALSE);
+
+            /* check generation
+             *
+             * OLD == age == 3 && old-bitmap && mark-bit (except incremental marking)
+             */
+            if (age > 0 && wb_unprotected_bit) {
+                fprintf(stderr, "check_rvalue_consistency: %s is not WB protected, but age is %d > 0.\n", obj_info(obj), age);
+                err++;
+            }
+
+            if (!is_marking(objspace) && uncollectible_bit && !mark_bit) {
+                fprintf(stderr, "check_rvalue_consistency: %s is uncollectible, but is not marked while !gc.\n", obj_info(obj));
+                err++;
+            }
+
+            if (!is_full_marking(objspace)) {
+                if (uncollectible_bit && age != RVALUE_OLD_AGE && !wb_unprotected_bit) {
+                    fprintf(stderr, "check_rvalue_consistency: %s is uncollectible, but not old (age: %d) and not WB unprotected.\n",
+                            obj_info(obj), age);
+                    err++;
+                }
+                if (remembered_bit && age != RVALUE_OLD_AGE) {
+                    fprintf(stderr, "check_rvalue_consistency: %s is remembered, but not old (age: %d).\n",
+                            obj_info(obj), age);
+                    err++;
+                }
+            }
+
+            /*
+             * check coloring
+             *
+             *               marking:false marking:true
+             * marked:false  white         *invalid*
+             * marked:true   black         grey
+             */
+            if (is_incremental_marking(objspace) && marking_bit) {
+                if (!is_marking(objspace) && !mark_bit) {
+                    fprintf(stderr, "check_rvalue_consistency: %s is marking, but not marked.\n", obj_info(obj));
+                    err++;
+                }
+            }
         }
     }
+    RB_VM_LOCK_LEAVE_NO_BARRIER();
 
     if (err > 0 && terminate) {
         rb_bug("check_rvalue_consistency_force: there is %d errors.", err);
     }
-
     return err;
 }
 
diff --git a/version.h b/version.h
index b09f0e654f..df2dd51989 100644
--- a/version.h
+++ b/version.h
@@ -12,7 +12,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 0
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 51
+#define RUBY_PATCHLEVEL 52
 
 #define RUBY_RELEASE_YEAR 2021
 #define RUBY_RELEASE_MONTH 3