diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cpp
@@ -92,10 +92,11 @@
   uptr res = map_res;
   if (!IsAligned(res, alignment)) {
     res = (map_res + alignment - 1) & ~(alignment - 1);
-    UnmapOrDie((void*)map_res, res - map_res);
+    if (IsAligned(map_res, GetPageSizeCached()))
+      UnmapOrDie((void*)map_res, res - map_res);
   }
   uptr end = res + size;
-  if (end != map_end)
+  if (end != map_end && IsAligned(end, GetPageSizeCached()))
     UnmapOrDie((void*)end, map_end - end);
   return (void*)res;
 }