From 25a4ab62ad61948a0ec776f4cc2b9b469b02dbba Mon Sep 17 00:00:00 2001
From: rabbitstack <rabbitstack7@gmail.com>
Date: Thu, 5 Mar 2026 18:51:05 +0100
Subject: [PATCH] perf(symbolizer): Cache unsuccessful debug help resolutions

If the process handle can't be acquired or the symbol handler initialization fails, we cache the symbol info to avoid hammering the OpenProcess API indefinitely.
---
 pkg/symbolize/symbolizer.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/pkg/symbolize/symbolizer.go b/pkg/symbolize/symbolizer.go
index d8c779fc8..ee5e8d98e 100644
--- a/pkg/symbolize/symbolizer.go
+++ b/pkg/symbolize/symbolizer.go
@@ -535,12 +535,16 @@ func (s *Symbolizer) produceFrame(addr va.Address, e *event.Event) callstack.Fra
 	if !ok {
 		handle, err := windows.OpenProcess(windows.SYNCHRONIZE|windows.PROCESS_QUERY_INFORMATION, false, pid)
 		if err != nil {
+			// symbol handler initalization fails, cache
+			// the symbol for future lookups
+			s.cacheSymbolUnbacked(pid, addr, &frame)
 			return frame
 		}
 		// initialize symbol handler
 		opts := uint32(sys.SymUndname | sys.SymCaseInsensitive | sys.SymAutoPublics | sys.SymOmapFindNearest | sys.SymDeferredLoads)
 		err = s.r.Initialize(handle, opts)
 		if err != nil {
+			s.cacheSymbolUnbacked(pid, addr, &frame)
 			return frame
 		}
 		proc = &process{pid, handle, time.Now(), 1}
@@ -654,6 +658,13 @@ func (s *Symbolizer) cacheSymbol(pid uint32, addr va.Address, frame *callstack.F
 	}
 }
 
+func (s *Symbolizer) cacheSymbolUnbacked(pid uint32, addr va.Address, frame *callstack.Frame) {
+	if frame.Module == "?" {
+		frame.Module = "unbacked"
+	}
+	s.cacheSymbol(pid, addr, frame)
+}
+
 func (s *Symbolizer) cleanSym() {
 	s.mu.Lock()
 	defer s.mu.Unlock()