diff --git a/vulkan/libvulkan/Android.bp b/vulkan/libvulkan/Android.bp
index 879d2d0..7e7fdc4 100644
--- a/vulkan/libvulkan/Android.bp
+++ b/vulkan/libvulkan/Android.bp
@@ -41,14 +41,9 @@
     aconfig_declarations: "libvulkan_flags",
 }
 
-cc_library_shared {
-    name: "libvulkan",
-    llndk: {
-        symbol_file: "libvulkan.map.txt",
-        export_llndk_headers: [
-            "vulkan_headers",
-        ],
-    },
+cc_defaults {
+    name: "libvulkan_defaults",
+
     sanitize: {
         misc_undefined: ["integer"],
     },
@@ -81,6 +76,34 @@
         "-Wno-global-constructors",
         "-Wno-zero-length-array",
     ],
+}
+
+cc_library {
+    name: "libvulkanallocator",
+    defaults: ["libvulkan_defaults"],
+    cflags: [
+        // This code uses malloc_usable_size(),
+        // and thus can't be built with _FORTIFY_SOURCE=3.
+        "-U_FORTIFY_SOURCE",
+        "-D_FORTIFY_SOURCE=2",
+    ],
+    srcs: [
+        "allocator.cpp",
+    ],
+    header_libs: [
+        "vulkan_headers",
+    ],
+}
+
+cc_library_shared {
+    name: "libvulkan",
+    defaults: ["libvulkan_defaults"],
+    llndk: {
+        symbol_file: "libvulkan.map.txt",
+        export_llndk_headers: [
+            "vulkan_headers",
+        ],
+    },
 
     srcs: [
         "api.cpp",
@@ -124,6 +147,7 @@
     ],
     static_libs: [
         "libgrallocusage",
+        "libvulkanallocator",
         "libvulkanflags",
     ],
 }
diff --git a/vulkan/libvulkan/allocator.cpp b/vulkan/libvulkan/allocator.cpp
new file mode 100644
index 0000000..2ca0586
--- /dev/null
+++ b/vulkan/libvulkan/allocator.cpp
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
+#include "allocator.h"
+
+#include <stdlib.h>
+
+#include <algorithm>
+
+#include <log/log.h>
+
+// #define ENABLE_ALLOC_CALLSTACKS 1
+#if ENABLE_ALLOC_CALLSTACKS
+#include <utils/CallStack.h>
+#define ALOGD_CALLSTACK(...)                             \
+    do {                                                 \
+        ALOGD(__VA_ARGS__);                              \
+        android::CallStack callstack;                    \
+        callstack.update();                              \
+        callstack.log(LOG_TAG, ANDROID_LOG_DEBUG, "  "); \
+    } while (false)
+#else
+#define ALOGD_CALLSTACK(...) \
+    do {                     \
+    } while (false)
+#endif
+
+namespace vulkan {
+namespace driver {
+
+namespace {
+
+VKAPI_ATTR void* DefaultAllocate(void*,
+                                 size_t size,
+                                 size_t alignment,
+                                 VkSystemAllocationScope) {
+    void* ptr = nullptr;
+    // Vulkan requires 'alignment' to be a power of two, but posix_memalign
+    // additionally requires that it be at least sizeof(void*).
+    int ret = posix_memalign(&ptr, std::max(alignment, sizeof(void*)), size);
+    ALOGD_CALLSTACK("Allocate: size=%zu align=%zu => (%d) %p", size, alignment,
+                    ret, ptr);
+    return ret == 0 ? ptr : nullptr;
+}
+
+// This function is marked `noinline` so that LLVM can't infer an object size
+// for FORTIFY through it, given that it's abusing malloc_usable_size().
+__attribute__((__noinline__))
+VKAPI_ATTR void* DefaultReallocate(void*,
+                                   void* ptr,
+                                   size_t size,
+                                   size_t alignment,
+                                   VkSystemAllocationScope) {
+    if (size == 0) {
+        free(ptr);
+        return nullptr;
+    }
+
+    // TODO(b/143295633): Right now we never shrink allocations; if the new
+    // request is smaller than the existing chunk, we just continue using it.
+    // Right now the loader never reallocs, so this doesn't matter. If that
+    // changes, or if this code is copied into some other project, this should
+    // probably have a heuristic to allocate-copy-free when doing so will save
+    // "enough" space.
+    size_t old_size = ptr ? malloc_usable_size(ptr) : 0;
+    if (size <= old_size)
+        return ptr;
+
+    void* new_ptr = nullptr;
+    if (posix_memalign(&new_ptr, std::max(alignment, sizeof(void*)), size) != 0)
+        return nullptr;
+    if (ptr) {
+        memcpy(new_ptr, ptr, std::min(old_size, size));
+        free(ptr);
+    }
+    return new_ptr;
+}
+
+VKAPI_ATTR void DefaultFree(void*, void* ptr) {
+    ALOGD_CALLSTACK("Free: %p", ptr);
+    free(ptr);
+}
+
+}  // anonymous namespace
+
+const VkAllocationCallbacks& GetDefaultAllocator() {
+    static const VkAllocationCallbacks kDefaultAllocCallbacks = {
+        .pUserData = nullptr,
+        .pfnAllocation = DefaultAllocate,
+        .pfnReallocation = DefaultReallocate,
+        .pfnFree = DefaultFree,
+    };
+
+    return kDefaultAllocCallbacks;
+}
+
+}  // namespace driver
+}  // namespace vulkan
diff --git a/vulkan/libvulkan/allocator.h b/vulkan/libvulkan/allocator.h
new file mode 100644
index 0000000..9095e92
--- /dev/null
+++ b/vulkan/libvulkan/allocator.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vulkan/vulkan.h>
+
+namespace vulkan {
+namespace driver {
+
+const VkAllocationCallbacks& GetDefaultAllocator();
+
+}  // namespace driver
+}  // namespace vulkan
diff --git a/vulkan/libvulkan/driver.cpp b/vulkan/libvulkan/driver.cpp
index 7d0f545..28c1b5f 100644
--- a/vulkan/libvulkan/driver.cpp
+++ b/vulkan/libvulkan/driver.cpp
@@ -50,22 +50,6 @@
 
 extern "C" android_namespace_t* android_get_exported_namespace(const char*);
 
-// #define ENABLE_ALLOC_CALLSTACKS 1
-#if ENABLE_ALLOC_CALLSTACKS
-#include <utils/CallStack.h>
-#define ALOGD_CALLSTACK(...)                             \
-    do {                                                 \
-        ALOGD(__VA_ARGS__);                              \
-        android::CallStack callstack;                    \
-        callstack.update();                              \
-        callstack.log(LOG_TAG, ANDROID_LOG_DEBUG, "  "); \
-    } while (false)
-#else
-#define ALOGD_CALLSTACK(...) \
-    do {                     \
-    } while (false)
-#endif
-
 namespace vulkan {
 namespace driver {
 
@@ -829,54 +813,6 @@
     }
 }
 
-VKAPI_ATTR void* DefaultAllocate(void*,
-                                 size_t size,
-                                 size_t alignment,
-                                 VkSystemAllocationScope) {
-    void* ptr = nullptr;
-    // Vulkan requires 'alignment' to be a power of two, but posix_memalign
-    // additionally requires that it be at least sizeof(void*).
-    int ret = posix_memalign(&ptr, std::max(alignment, sizeof(void*)), size);
-    ALOGD_CALLSTACK("Allocate: size=%zu align=%zu => (%d) %p", size, alignment,
-                    ret, ptr);
-    return ret == 0 ? ptr : nullptr;
-}
-
-VKAPI_ATTR void* DefaultReallocate(void*,
-                                   void* ptr,
-                                   size_t size,
-                                   size_t alignment,
-                                   VkSystemAllocationScope) {
-    if (size == 0) {
-        free(ptr);
-        return nullptr;
-    }
-
-    // TODO(b/143295633): Right now we never shrink allocations; if the new
-    // request is smaller than the existing chunk, we just continue using it.
-    // Right now the loader never reallocs, so this doesn't matter. If that
-    // changes, or if this code is copied into some other project, this should
-    // probably have a heuristic to allocate-copy-free when doing so will save
-    // "enough" space.
-    size_t old_size = ptr ? malloc_usable_size(ptr) : 0;
-    if (size <= old_size)
-        return ptr;
-
-    void* new_ptr = nullptr;
-    if (posix_memalign(&new_ptr, std::max(alignment, sizeof(void*)), size) != 0)
-        return nullptr;
-    if (ptr) {
-        memcpy(new_ptr, ptr, std::min(old_size, size));
-        free(ptr);
-    }
-    return new_ptr;
-}
-
-VKAPI_ATTR void DefaultFree(void*, void* ptr) {
-    ALOGD_CALLSTACK("Free: %p", ptr);
-    free(ptr);
-}
-
 InstanceData* AllocateInstanceData(const VkAllocationCallbacks& allocator) {
     void* data_mem = allocator.pfnAllocation(
         allocator.pUserData, sizeof(InstanceData), alignof(InstanceData),
@@ -916,17 +852,6 @@
     return Hal::Open();
 }
 
-const VkAllocationCallbacks& GetDefaultAllocator() {
-    static const VkAllocationCallbacks kDefaultAllocCallbacks = {
-        .pUserData = nullptr,
-        .pfnAllocation = DefaultAllocate,
-        .pfnReallocation = DefaultReallocate,
-        .pfnFree = DefaultFree,
-    };
-
-    return kDefaultAllocCallbacks;
-}
-
 PFN_vkVoidFunction GetInstanceProcAddr(VkInstance instance, const char* pName) {
     const ProcHook* hook = GetProcHook(pName);
     if (!hook)
diff --git a/vulkan/libvulkan/driver.h b/vulkan/libvulkan/driver.h
index 4b855e5..fa85dd5 100644
--- a/vulkan/libvulkan/driver.h
+++ b/vulkan/libvulkan/driver.h
@@ -27,6 +27,7 @@
 #include <vulkan/vulkan.h>
 #include <hardware/hwvulkan.h>
 
+#include "allocator.h"
 #include "api_gen.h"
 #include "driver_gen.h"
 #include "debug_report.h"
@@ -102,7 +103,6 @@
 };
 
 bool OpenHAL();
-const VkAllocationCallbacks& GetDefaultAllocator();
 
 void QueryPresentationProperties(
     VkPhysicalDevice physicalDevice,