fix(inputs.tail): Fix data race when cleaning up unused tailers

plugins/inputs/tail/tail.go

@@ -351,16 +351,14 @@ func (t *Tail) cleanupUnusedTailers(currentFiles map[string]bool) error {
 			// We need to stop tailing it and remove it from our list
 			t.Log.Debugf("Removing tailer for %q as it's no longer in the glob pattern", file)
 
-			// Save the current offset for potential future use
-			if !t.Pipe {
-				offset, err := tailer.Tell()
-				if err == nil {
-					t.Log.Debugf("Recording offset %d for %q", offset, tailer.Filename)
-					t.offsets[tailer.Filename] = offset
-				} else {
-					t.Log.Errorf("Recording offset for %q: %s", tailer.Filename, err.Error())
-				}
-			}
+			// NOTE: We intentionally do NOT save the offset here because:
+			// 1. There's a data race in the tail library between Tell() and reopen()
+			//    that could cause undefined behavior or incorrect offsets
+			// 2. Files removed from glob patterns are typically rotated logs that
+			//    won't return with the same name
+			// 3. The Stop() method will save offsets safely when the plugin stops
+			// This trade-off prioritizes stability over rare edge cases where a
+			// file temporarily doesn't match the glob and returns later.
 
 			// Stop the tailer
 			err := tailer.Stop()

plugins/inputs/tail/tail_test.go

@@ -1152,7 +1152,6 @@ func TestTailNoLeak(t *testing.T) {
 // TestTailCleanupUnusedTailers tests the fix for file descriptor leaks
 // by ensuring tailers for files that no longer match the glob pattern are cleaned up
 func TestTailCleanupUnusedTailers(t *testing.T) {
-	t.Skip("Test disabled due to data race - see issue #[17571] for fix progress")
 	// Create a temp directory for our test files
 	tempDir := t.TempDir()