Index: compiler-rt/lib/scudo/standalone/common.h
===================================================================
--- compiler-rt/lib/scudo/standalone/common.h
+++ compiler-rt/lib/scudo/standalone/common.h
@@ -149,6 +149,7 @@
 #define MAP_NOACCESS (1U << 1)
 #define MAP_RESIZABLE (1U << 2)
 #define MAP_MEMTAG (1U << 3)
+#define MAP_PRECOMMIT (1U << 4)
 
 // Our platform memory mapping use is restricted to 3 scenarios:
 // - reserve memory at a random address (MAP_NOACCESS);
Index: compiler-rt/lib/scudo/standalone/fuchsia.cpp
===================================================================
--- compiler-rt/lib/scudo/standalone/fuchsia.cpp
+++ compiler-rt/lib/scudo/standalone/fuchsia.cpp
@@ -112,6 +112,17 @@
       dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY ? Size : 0);
     return nullptr;
   }
+
+  if (Flags & MAP_PRECOMMIT) {
+    Status = _zx_vmo_op_range(Vmo, ZX_VMO_OP_COMMIT, VmoSize, Size,
+                              /*buffer=*/nullptr, /*buffer_size=*/0);
+  }
+  if (UNLIKELY(Status != ZX_OK)) {
+    if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
+      dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY ? Size : 0);
+    return nullptr;
+  }
+
   if (Data)
     Data->VmoSize += Size;
 
Index: compiler-rt/lib/scudo/standalone/release.h
===================================================================
--- compiler-rt/lib/scudo/standalone/release.h
+++ compiler-rt/lib/scudo/standalone/release.h
@@ -109,7 +109,7 @@
     } else {
       Buffer = reinterpret_cast<uptr *>(
           map(nullptr, roundUpTo(BufferSize, getPageSizeCached()),
-              "scudo:counters", MAP_ALLOWNOMEM, &MapData));
+              "scudo:counters", MAP_ALLOWNOMEM | MAP_PRECOMMIT, &MapData));
     }
   }