diff --git a/libc/bionic/system_property_api.cpp b/libc/bionic/system_property_api.cpp
index f2e1032..10d1bb3 100644
--- a/libc/bionic/system_property_api.cpp
+++ b/libc/bionic/system_property_api.cpp
@@ -35,6 +35,8 @@
 #include "private/bionic_defs.h"
 
 static SystemProperties system_properties;
+static_assert(__is_trivially_constructible(SystemProperties),
+              "System Properties must be trivially constructable");
 
 // This is public because it was exposed in the NDK. As of 2017-01, ~60 apps reference this symbol.
 // It is set to nullptr and never modified.
diff --git a/libc/system_properties/include/system_properties/system_properties.h b/libc/system_properties/include/system_properties/system_properties.h
index 37fe6c0..52ffcaf 100644
--- a/libc/system_properties/include/system_properties/system_properties.h
+++ b/libc/system_properties/include/system_properties/system_properties.h
@@ -29,6 +29,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <sys/param.h>
 #include <sys/system_properties.h>
 
 #include "contexts.h"
@@ -40,12 +41,13 @@
 
 class SystemProperties {
  public:
+  friend struct LocalPropertyTestState;
+  friend class SystemPropertiesTest;
   // Note that system properties are initialized before libc calls static initializers, so
   // doing any initialization in this constructor is an error.  Even a Constructor that zero
   // initializes this class will clobber the previous property initialization.
   // We rely on the static SystemProperties in libc to be placed in .bss and zero initialized.
-  SystemProperties() {
-  }
+  SystemProperties() = default;
   // Special constructor for testing that also zero initializes the important members.
   explicit SystemProperties(bool initialized) : initialized_(initialized) {
   }
@@ -71,23 +73,17 @@
   const prop_info* FindNth(unsigned n);
   int Foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie);
 
-  Contexts* contexts() {
-    return reinterpret_cast<Contexts*>(&contexts_union_);
-  }
-
  private:
-  // We don't want to use new or malloc in properties (b/31659220), and since these classes
-  // are small enough and we place them in a union.  See the above note about Constructors
-  // for why there is a no-op constructor here.
-  union ContextsUnion {
-    ContextsUnion() {
-    }
-    ~ContextsUnion() {
-    }
-    ContextsSerialized contexts_serialized;
-    ContextsSplit contexts_split;
-    ContextsPreSplit contexts_pre_split;
-  } contexts_union_;
+  // We don't want to use new or malloc in properties (b/31659220), and we don't want to waste a
+  // full page by using mmap(), so we set aside enough space to create any context of the three
+  // contexts.
+  static constexpr size_t kMaxContextsAlign =
+      MAX(alignof(ContextsSerialized), MAX(alignof(ContextsSplit), alignof(ContextsPreSplit)));
+  static constexpr size_t kMaxContextsSize =
+      MAX(sizeof(ContextsSerialized), MAX(sizeof(ContextsSplit), sizeof(ContextsPreSplit)));
+  alignas(kMaxContextsAlign) char contexts_data_[kMaxContextsSize];
+  Contexts* contexts_;
+
   bool initialized_;
   char property_filename_[PROP_FILENAME_MAX];
 };
diff --git a/libc/system_properties/system_properties.cpp b/libc/system_properties/system_properties.cpp
index c610df2..7c48b8e 100644
--- a/libc/system_properties/system_properties.cpp
+++ b/libc/system_properties/system_properties.cpp
@@ -63,7 +63,7 @@
   ErrnoRestorer errno_restorer;
 
   if (initialized_) {
-    contexts()->ResetAccess();
+    contexts_->ResetAccess();
     return true;
   }
 
@@ -74,19 +74,19 @@
 
   if (is_dir(property_filename_)) {
     if (access("/dev/__properties__/property_info", R_OK) == 0) {
-      new (&contexts_union_.contexts_serialized) ContextsSerialized();
-      if (!contexts_union_.contexts_serialized.Initialize(false, property_filename_, nullptr)) {
+      contexts_ = new (contexts_data_) ContextsSerialized();
+      if (!contexts_->Initialize(false, property_filename_, nullptr)) {
         return false;
       }
     } else {
-      new (&contexts_union_.contexts_split) ContextsSplit();
-      if (!contexts_union_.contexts_split.Initialize(false, property_filename_, nullptr)) {
+      contexts_ = new (contexts_data_) ContextsSplit();
+      if (!contexts_->Initialize(false, property_filename_, nullptr)) {
         return false;
       }
     }
   } else {
-    new (&contexts_union_.contexts_pre_split) ContextsPreSplit();
-    if (!contexts_union_.contexts_pre_split.Initialize(false, property_filename_, nullptr)) {
+    contexts_ = new (contexts_data_) ContextsPreSplit();
+    if (!contexts_->Initialize(false, property_filename_, nullptr)) {
       return false;
     }
   }
@@ -100,8 +100,8 @@
   }
   strcpy(property_filename_, filename);
 
-  new (&contexts_union_.contexts_serialized) ContextsSerialized();
-  if (!contexts_union_.contexts_serialized.Initialize(true, property_filename_, fsetxattr_failed)) {
+  contexts_ = new (contexts_data_) ContextsSerialized();
+  if (!contexts_->Initialize(true, property_filename_, fsetxattr_failed)) {
     return false;
   }
   initialized_ = true;
@@ -113,7 +113,7 @@
     return -1;
   }
 
-  prop_area* pa = contexts()->GetSerialPropArea();
+  prop_area* pa = contexts_->GetSerialPropArea();
   if (!pa) {
     return -1;
   }
@@ -127,7 +127,7 @@
     return nullptr;
   }
 
-  prop_area* pa = contexts()->GetPropAreaForName(name);
+  prop_area* pa = contexts_->GetPropAreaForName(name);
   if (!pa) {
     async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
     return nullptr;
@@ -231,7 +231,7 @@
     return -1;
   }
 
-  prop_area* pa = contexts()->GetSerialPropArea();
+  prop_area* pa = contexts_->GetSerialPropArea();
   if (!pa) {
     return -1;
   }
@@ -269,12 +269,12 @@
     return -1;
   }
 
-  prop_area* serial_pa = contexts()->GetSerialPropArea();
+  prop_area* serial_pa = contexts_->GetSerialPropArea();
   if (serial_pa == nullptr) {
     return -1;
   }
 
-  prop_area* pa = contexts()->GetPropAreaForName(name);
+  prop_area* pa = contexts_->GetPropAreaForName(name);
   if (!pa) {
     async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
     return -1;
@@ -319,7 +319,7 @@
       return -1;
     }
 
-    prop_area* serial_pa = contexts()->GetSerialPropArea();
+    prop_area* serial_pa = contexts_->GetSerialPropArea();
     if (serial_pa == nullptr) {
       return -1;
     }
@@ -364,7 +364,7 @@
     return -1;
   }
 
-  contexts()->ForEach(propfn, cookie);
+  contexts_->ForEach(propfn, cookie);
 
   return 0;
 }