1 files changed, 3 insertions, 3 deletions
diff --git a/lib/esan/esan.cpp b/lib/esan/esan.cpp
index 09b530b6645f6..44b8032caa1a4 100644
--- a/lib/esan/esan.cpp
+++ b/lib/esan/esan.cpp
@@ -163,15 +163,15 @@ static void initializeShadow() {
     VPrintf(1, "Shadow #%d: [%zx-%zx) (%zuGB)\n", i, ShadowStart, ShadowEnd,
             (ShadowEnd - ShadowStart) >> 30);
 
-    uptr Map;
+    uptr Map = 0;
     if (__esan_which_tool == ESAN_WorkingSet) {
       // We want to identify all shadow pages that are touched so we start
       // out inaccessible.
       Map = (uptr)MmapFixedNoAccess(ShadowStart, ShadowEnd- ShadowStart,
                                     "shadow");
     } else {
-      Map = (uptr)MmapFixedNoReserve(ShadowStart, ShadowEnd - ShadowStart,
-                                     "shadow");
+      if (MmapFixedNoReserve(ShadowStart, ShadowEnd - ShadowStart, "shadow"))
+        Map = ShadowStart;
     }
     if (Map != ShadowStart) {
       Printf("FATAL: EfficiencySanitizer failed to map its shadow memory.\n");