diff --git a/bootstraptest/test_ractor.rb b/bootstraptest/test_ractor.rb
index b296ad0331..fcdd31ac2e 100644
--- a/bootstraptest/test_ractor.rb
+++ b/bootstraptest/test_ractor.rb
@@ -1361,6 +1361,28 @@ assert_equal 'true', %q{
   Ractor.shareable?(pr)
 }
 
+# Ractor.make_shareable(a_proc) makes inner structure shareable and freezes it
+assert_equal 'true,true,true,true', %q{
+  class Proc
+    attr_reader :obj
+    def initialize
+      @obj = Object.new
+    end
+  end
+
+  pr = Ractor.current.instance_eval do
+    Proc.new {}
+  end
+
+  results = []
+  Ractor.make_shareable(pr)
+  results << Ractor.shareable?(pr)
+  results << pr.frozen?
+  results << Ractor.shareable?(pr.obj)
+  results << pr.obj.frozen?
+  results.map(&:to_s).join(',')
+}
+
 # Ractor.shareable?(recursive_objects)
 assert_equal '[false, false]', %q{
   y = []
@@ -1389,6 +1411,21 @@ assert_equal '[C, M]', %q{
   Ractor.make_shareable(ary = [C, M])
 }
 
+# Ractor.make_shareable with curried proc checks isolation of original proc
+assert_equal 'isolation error', %q{
+  a = Object.new
+  orig = proc { a }
+  curried = orig.curry
+
+  begin
+    Ractor.make_shareable(curried)
+  rescue Ractor::IsolationError
+    'isolation error'
+  else
+    'no error'
+  end
+}
+
 # define_method() can invoke different Ractor's proc if the proc is shareable.
 assert_equal '1', %q{
   class C
diff --git a/ractor.c b/ractor.c
index e0ee977a42..fc4d9fb02e 100644
--- a/ractor.c
+++ b/ractor.c
@@ -3045,7 +3045,7 @@ rb_obj_traverse(VALUE obj,
 }
 
 static int
-frozen_shareable_p(VALUE obj, bool *made_shareable)
+allow_frozen_shareable_p(VALUE obj)
 {
     if (!RB_TYPE_P(obj, T_DATA)) {
         return true;
@@ -3055,13 +3055,6 @@ frozen_shareable_p(VALUE obj, bool *made_shareable)
         if (type->flags & RUBY_TYPED_FROZEN_SHAREABLE) {
             return true;
         }
-        else if (made_shareable && rb_obj_is_proc(obj)) {
-            // special path to make shareable Proc.
-            rb_proc_ractor_make_shareable(obj);
-            *made_shareable = true;
-            VM_ASSERT(RB_OBJ_SHAREABLE_P(obj));
-            return false;
-        }
     }
 
     return false;
@@ -3071,20 +3064,24 @@ static enum obj_traverse_iterator_result
 make_shareable_check_shareable(VALUE obj)
 {
     VM_ASSERT(!SPECIAL_CONST_P(obj));
-    bool made_shareable = false;
 
     if (rb_ractor_shareable_p(obj)) {
         return traverse_skip;
     }
-    if (!frozen_shareable_p(obj, &made_shareable)) {
-        if (made_shareable) {
-            return traverse_skip;
+    else if (!allow_frozen_shareable_p(obj)) {
+        if (rb_obj_is_proc(obj)) {
+            rb_proc_ractor_make_shareable(obj);
+            return traverse_cont;
         }
         else {
             rb_raise(rb_eRactorError, "can not make shareable object for %"PRIsVALUE, obj);
         }
     }
 
+    if (RB_TYPE_P(obj, T_IMEMO)) {
+        return traverse_skip;
+    }
+
     if (!RB_OBJ_FROZEN_RAW(obj)) {
         rb_funcall(obj, idFreeze, 0);
 
@@ -3156,7 +3153,7 @@ shareable_p_enter(VALUE obj)
         return traverse_skip;
     }
     else if (RB_OBJ_FROZEN_RAW(obj) &&
-             frozen_shareable_p(obj, NULL)) {
+             allow_frozen_shareable_p(obj)) {
         return traverse_cont;
     }
 
diff --git a/vm.c b/vm.c
index f5bb777b75..d31759724e 100644
--- a/vm.c
+++ b/vm.c
@@ -1415,7 +1415,7 @@ rb_proc_ractor_make_shareable(VALUE self)
         proc->is_isolated = TRUE;
     }
 
-    FL_SET_RAW(self, RUBY_FL_SHAREABLE);
+    rb_obj_freeze(self);
     return self;
 }