Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -107,6 +107,10 @@
 #define times __times13
 #define wait3 __wait350
 #define wait4 __wait450
+// ctype(3) arrays
+extern const unsigned short *_ctype_tab_;
+extern const short *_toupper_tab_;
+extern const short *_tolower_tab_;
 #endif
 
 // Platform-specific options.
@@ -3164,7 +3168,15 @@
   if (locale)
     COMMON_INTERCEPTOR_READ_RANGE(ctx, locale, REAL(strlen)(locale) + 1);
   char *res = REAL(setlocale)(category, locale);
-  if (res) COMMON_INTERCEPTOR_WRITE_RANGE(ctx, res, REAL(strlen)(res) + 1);
+  if (res) {
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, res, REAL(strlen)(res) + 1);
+#if SANITIZER_NETBSD
+    // Valid array indices: -1 (EOF), 0, 1, .. 255
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, _ctype_tab_, 257 * sizeof(short));
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, _toupper_tab_, 257 * sizeof(short));
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, _tolower_tab_, 257 * sizeof(short));
+#endif
+  }
   return res;
 }