fix(filterlists): Resolve occasional FilterLists initialization failures

Improved module initialization and processing logic to enhance concurrency handling and ensure reliable
https://github.com/safing/portmaster/issues/1951

service/intel/filterlists/database.go

@@ -110,6 +110,7 @@ func processListFile(ctx context.Context, filter *scopedBloom, file *updates.Art
 		})
 	}
 
+	// Decode file and send entries to values channel.
 	startSafe(func() (err error) {
 		defer close(values)
 
@@ -117,6 +118,15 @@ func processListFile(ctx context.Context, filter *scopedBloom, file *updates.Art
 		return
 	})
 
+	// Wait for the module initialization to complete to ensure the filter is fully loaded.
+	// This avoids prolonged locks during filter updates caused by concurrent database loading.
+	select {
+	case <-moduleInitDone:
+	case <-time.After(time.Second * 20):
+		log.Warning("intel/filterlists: timeout waiting for module initialization")
+	}
+
+	// Process each entry and send records to records channel.
 	startSafe(func() error {
 		defer close(records)
 		for entry := range values {
@@ -128,6 +138,7 @@ func processListFile(ctx context.Context, filter *scopedBloom, file *updates.Art
 		return nil
 	})
 
+	// Persist records to the database.
 	persistRecords(startSafe, records)
 
 	return g.Wait()

service/intel/filterlists/module.go

@@ -45,14 +45,17 @@ func (fl *FilterLists) Stop() error {
 	return stop()
 }
 
-// booleans mainly used to decouple the module
-// during testing.
 var (
+	moduleInitDone chan struct{}
+
+	// booleans mainly used to decouple the module during testing.
 	ignoreUpdateEvents = abool.New()
 	ignoreNetEnvEvents = abool.New()
 )
 
 func init() {
+	moduleInitDone = make(chan struct{})
+
 	ignoreNetEnvEvents.Set()
 }
 
@@ -87,6 +90,10 @@ func start() error {
 	filterListLock.Lock()
 	defer filterListLock.Unlock()
 
+	// Signal that the module has been initialized.
+	// This indicates that the module is ready for use, with the default filter
+	defer close(moduleInitDone)
+
 	ver, err := getCacheDatabaseVersion()
 	if err == nil {
 		log.Debugf("intel/filterlists: cache database has version %s", ver.String())
@@ -108,6 +115,7 @@ func start() error {
 }
 
 func stop() error {
+	moduleInitDone = make(chan struct{})
 	filterListsLoaded = make(chan struct{})
 	return nil
 }