diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
@@ -1185,6 +1185,7 @@
 uptr GetMaxUserVirtualAddress() {
   static uptr max_vm = GetTaskInfoMaxAddress();
   if (max_vm != 0) {
+    CHECK_LE(max_vm - 1, SANITIZER_MMAP_RANGE_SIZE);
     return max_vm - 1;
   }