diff --git a/src/ctrl/ctrl_core.c b/src/ctrl/ctrl_core.c
index 7a60663f..faf87e31 100644
--- a/src/ctrl/ctrl_core.c
+++ b/src/ctrl/ctrl_core.c
@@ -3411,99 +3411,88 @@ ctrl_call_stack_from_thread(CTRL_Scope *scope, CTRL_EntityCtx *entity_ctx, CTRL_
   //- rjf: loop: try to grab cached call stack; request; wait
   //
   B32 can_request = !ins_atomic_u64_eval(&ctrl_state->ctrl_thread_run_state);
-  B32 did_request = 0;
-  OS_MutexScopeR(stripe->rw_mutex)
+  for(;;)
   {
-    CTRL_CallStackCacheNode *taken_node = 0;
-    for(;;)
+    //- rjf: step 1: [read-only] try to look for current call stack; wait if working
+    B32 node_exists = 0;
+    B32 node_stale = 1;
+    B32 node_working = 0;
+    OS_MutexScopeR(stripe->rw_mutex) for(;;)
     {
-      ////////////////////////////
-      //- rjf: try to grab cached
-      //
-      B32 is_good = 0;
-      B32 is_stale = 1;
-      B32 is_working = 0;
       CTRL_CallStackCacheNode *node = 0;
+      for(CTRL_CallStackCacheNode *n = slot->first; n != 0; n = n->next)
       {
-        for(CTRL_CallStackCacheNode *n = slot->first; n != 0; n = n->next)
+        if(ctrl_handle_match(n->thread, handle))
         {
-          if(ctrl_handle_match(n->thread, handle))
-          {
-            node = n;
-            is_good    = 1;
-            is_stale   = (reg_gen > n->reg_gen || mem_gen > n->mem_gen);
-            is_working = (n->working_count > 0);
-            call_stack = n->call_stack;
-            taken_node = node;
-            break;
-          }
+          node = n;
+          node_exists  = 1;
+          node_stale   = (reg_gen > n->reg_gen || mem_gen > n->mem_gen);
+          node_working = (n->working_count > 0);
+          break;
         }
       }
-      
-      ////////////////////////////
-      //- rjf: create node if needed
-      //
-      if(!is_good) OS_MutexScopeRWPromote(stripe->rw_mutex)
-      {
-        node = 0;
-        for(CTRL_CallStackCacheNode *n = slot->first; n != 0; n = n->next)
-        {
-          if(ctrl_handle_match(n->thread, handle))
-          {
-            node = n;
-            break;
-          }
-        }
-        if(node == 0)
-        {
-          node = push_array(stripe->arena, CTRL_CallStackCacheNode, 1);
-          DLLPushBack(slot->first, slot->last, node);
-          node->thread = thread->handle;
-        }
-      }
-      
-      ////////////////////////////
-      //- rjf: request if needed
-      //
-      if(can_request && node != 0 && !is_working && is_stale)
-      {
-        if(ctrl_u2csb_enqueue_req(thread->handle, endt_us))
-        {
-          did_request = 1;
-          is_working = 1;
-          ins_atomic_u64_inc_eval(&node->working_count);
-          DeferLoop(os_rw_mutex_drop_r(stripe->rw_mutex), os_rw_mutex_take_r(stripe->rw_mutex))
-          {
-            async_push_work(ctrl_call_stack_build_work, .priority = high_priority ? ASYNC_Priority_High : ASYNC_Priority_Low);
-          }
-        }
-      }
-      
-      ////////////////////////////
-      //- rjf: good, or timeout? -> exit
-      //
-      if(!can_request || !is_stale || os_now_microseconds() >= endt_us)
+      if(node_exists && (!node_stale || os_now_microseconds() >= endt_us))
       {
+        call_stack = node->call_stack;
+        ctrl_scope_touch_call_stack_node__stripe_r_guarded(scope, stripe, node);
         break;
       }
-      
-      ////////////////////////////
-      //- rjf: time to wait for new result? -> wait
-      //
-      if(did_request && !is_working)
-      {
-        break;
-      }
-      else if(did_request)
+      else if(node_working)
       {
         os_condition_variable_wait_rw_r(stripe->cv, stripe->rw_mutex, endt_us);
       }
+      else
+      {
+        break;
+      }
     }
-    if(taken_node != 0)
+    
+    //- rjf: step 2: [write] node does not exist => create; request if new or stale
+    CTRL_CallStackCacheNode *node_to_request = 0;
+    if(!node_exists || node_stale) OS_MutexScopeW(stripe->rw_mutex)
     {
-      ctrl_scope_touch_call_stack_node__stripe_r_guarded(scope, stripe, taken_node);
+      CTRL_CallStackCacheNode *node = 0;
+      for(CTRL_CallStackCacheNode *n = slot->first; n != 0; n = n->next)
+      {
+        if(ctrl_handle_match(n->thread, handle))
+        {
+          node = n;
+          break;
+        }
+      }
+      if(node == 0)
+      {
+        node = push_array(stripe->arena, CTRL_CallStackCacheNode, 1);
+        DLLPushBack(slot->first, slot->last, node);
+        node->thread = thread->handle;
+      }
+      if(can_request && node->working_count == 0)
+      {
+        node->working_count += 1;
+        node_to_request = node;
+      }
+    }
+    
+    //- rjf: step 3: request if needed
+    if(node_to_request != 0)
+    {
+      if(ctrl_u2csb_enqueue_req(thread->handle, endt_us))
+      {
+        async_push_work(ctrl_call_stack_build_work, .priority = high_priority ? ASYNC_Priority_High : ASYNC_Priority_Low);
+      }
+      else OS_MutexScopeW(stripe->rw_mutex)
+      {
+        node_to_request->working_count -= 1;
+      }
+    }
+    
+    //- rjf: step 4: out of time => exit
+    if(os_now_microseconds() >= endt_us)
+    {
+      break;
     }
   }
+  
   return call_stack;
 }