From 9d802edf0a6c3b0c7c95c283f4e20ae110c31457 Mon Sep 17 00:00:00 2001
From: Alexander Solovets <asolovets@gmail.com>
Date: Sun, 17 May 2026 08:53:49 +1000
Subject: [PATCH] Fix Device::availableMemory crash on Vulkan 1.0 instances

vkGetPhysicalDeviceMemoryProperties2 and VkPhysicalDeviceMemoryBudgetPropertiesEXT
were called unconditionally, but the former requires Vulkan 1.1 and the latter
requires VK_EXT_memory_budget. On a 1.0 instance this triggered undefined
behaviour and crashed Lavapipe during scene compilation. Gate the 1.1 path on
both preconditions and fall back to vkGetPhysicalDeviceMemoryProperties with
heap sizes when either is missing.
---
 src/vsg/vk/Device.cpp | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/src/vsg/vk/Device.cpp b/src/vsg/vk/Device.cpp
index 9fe862597..5acdfdc47 100644
--- a/src/vsg/vk/Device.cpp
+++ b/src/vsg/vk/Device.cpp
@@ -208,17 +208,30 @@ bool Device::supportsDeviceExtension(const char* extensionName) const
 
 VkDeviceSize Device::availableMemory(VkMemoryPropertyFlags memoryPropertiesFlags, double allocatedMemoryLimit) const
 {
-    VkPhysicalDeviceMemoryBudgetPropertiesEXT memoryBudget;
-    memoryBudget.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_BUDGET_PROPERTIES_EXT;
-    memoryBudget.pNext = nullptr;
+    // vkGetPhysicalDeviceMemoryProperties2 requires Vulkan 1.1, and the chained
+    // VkPhysicalDeviceMemoryBudgetPropertiesEXT additionally requires VK_EXT_memory_budget.
+    // Fall back to the 1.0 query (no live budget tracking) when either is missing.
+    const bool useBudget = supportsApiVersion(VK_API_VERSION_1_1) &&
+                           supportsDeviceExtension(VK_EXT_MEMORY_BUDGET_EXTENSION_NAME);
 
-    VkPhysicalDeviceMemoryProperties2 dmp;
-    dmp.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2;
-    dmp.pNext = &memoryBudget;
+    VkPhysicalDeviceMemoryProperties memoryProperties;
+    VkPhysicalDeviceMemoryBudgetPropertiesEXT memoryBudget = {};
 
-    vkGetPhysicalDeviceMemoryProperties2(*(getPhysicalDevice()), &dmp);
+    if (useBudget)
+    {
+        memoryBudget.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_BUDGET_PROPERTIES_EXT;
+
+        VkPhysicalDeviceMemoryProperties2 dmp = {};
+        dmp.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2;
+        dmp.pNext = &memoryBudget;
 
-    auto& memoryProperties = dmp.memoryProperties;
+        vkGetPhysicalDeviceMemoryProperties2(*(getPhysicalDevice()), &dmp);
+        memoryProperties = dmp.memoryProperties;
+    }
+    else
+    {
+        vkGetPhysicalDeviceMemoryProperties(*(getPhysicalDevice()), &memoryProperties);
+    }
 
     VkDeviceSize availableSpace = 0;
     for (uint32_t i = 0; i < memoryProperties.memoryTypeCount; ++i)
@@ -227,8 +240,10 @@ VkDeviceSize Device::availableMemory(VkMemoryPropertyFlags memoryPropertiesFlags
         {
             uint32_t heapIndex = memoryProperties.memoryTypes[i].heapIndex;
 
-            VkDeviceSize heapBudget = static_cast<VkDeviceSize>(static_cast<double>(memoryBudget.heapBudget[heapIndex]) * allocatedMemoryLimit);
-            VkDeviceSize heapUsage = memoryBudget.heapUsage[heapIndex];
+            VkDeviceSize heapBudget = useBudget ? memoryBudget.heapBudget[heapIndex] : memoryProperties.memoryHeaps[heapIndex].size;
+            VkDeviceSize heapUsage = useBudget ? memoryBudget.heapUsage[heapIndex] : 0;
+
+            heapBudget = static_cast<VkDeviceSize>(static_cast<double>(heapBudget) * allocatedMemoryLimit);
             VkDeviceSize heapAvailable = (heapUsage < heapBudget) ? heapBudget - heapUsage : 0;
             availableSpace += heapAvailable;