diff --git a/libc/malloc_debug/Unreachable.cpp b/libc/malloc_debug/Unreachable.cpp
new file mode 100644
index 0000000..af47257
--- /dev/null
+++ b/libc/malloc_debug/Unreachable.cpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <atomic>
+#include <string>
+
+#include <memunreachable/memunreachable.h>
+#include <platform/bionic/macros.h>
+
+#include "Config.h"
+#include "Unreachable.h"
+#include "debug_log.h"
+
+std::atomic_bool Unreachable::do_check_;
+
+static void EnableUnreachableCheck(int, struct siginfo*, void*) {
+  Unreachable::EnableCheck();
+}
+
+void Unreachable::CheckIfRequested(const Config& config) {
+  if ((config.options() & CHECK_UNREACHABLE_ON_SIGNAL) && do_check_.exchange(false)) {
+    info_log("Starting to check for unreachable memory.");
+    if (!LogUnreachableMemory(false, 100)) {
+      error_log("Unreachable check failed, run setenforce 0 and try again.");
+    }
+  }
+}
+
+bool Unreachable::Initialize(const Config& config) {
+  if (!(config.options() & CHECK_UNREACHABLE_ON_SIGNAL)) {
+    return true;
+  }
+
+  struct sigaction64 unreachable_act = {};
+  unreachable_act.sa_sigaction = EnableUnreachableCheck;
+  unreachable_act.sa_flags = SA_RESTART | SA_SIGINFO | SA_ONSTACK;
+  if (sigaction64(config.check_unreachable_signal(), &unreachable_act, nullptr) != 0) {
+    error_log("Unable to set up check unreachable signal function: %s", strerror(errno));
+    return false;
+  }
+
+  if (config.options() & VERBOSE) {
+    info_log("%s: Run: 'kill -%d %d' to check for unreachable memory.", getprogname(),
+             config.check_unreachable_signal(), getpid());
+  }
+
+  return true;
+}