SDL: GPU Vulkan: Fix render pass race (#12587)

SDL Commits
1 
From c696e93180a7a57991161798400adc7c05af0d8b Mon Sep 17 00:00:00 2001
From: Evan Hemsley <[EMAIL REDACTED]>
Date: Wed, 19 Mar 2025 13:32:14 -0700
Subject: [PATCH] GPU Vulkan: Fix render pass race (#12587)

---
 src/gpu/vulkan/SDL_gpu_vulkan.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/gpu/vulkan/SDL_gpu_vulkan.c b/src/gpu/vulkan/SDL_gpu_vulkan.c
index bd3910bd7ba0d..5803a7aedc7d9 100644
--- a/src/gpu/vulkan/SDL_gpu_vulkan.c
+++ b/src/gpu/vulkan/SDL_gpu_vulkan.c
@@ -1175,6 +1175,7 @@ struct VulkanRenderer
     SDL_Mutex *submitLock;
     SDL_Mutex *acquireCommandBufferLock;
     SDL_Mutex *acquireUniformBufferLock;
+    SDL_Mutex *renderPassFetchLock;
     SDL_Mutex *framebufferFetchLock;
     SDL_Mutex *windowLock;
 
@@ -4889,6 +4890,7 @@ static void VULKAN_DestroyDevice(
     SDL_DestroyMutex(renderer->submitLock);
     SDL_DestroyMutex(renderer->acquireCommandBufferLock);
     SDL_DestroyMutex(renderer->acquireUniformBufferLock);
+    SDL_DestroyMutex(renderer->renderPassFetchLock);
     SDL_DestroyMutex(renderer->framebufferFetchLock);
     SDL_DestroyMutex(renderer->windowLock);
 
@@ -7034,12 +7036,15 @@ static VkRenderPass VULKAN_INTERNAL_FetchRenderPass(
         key.depthStencilTargetDescription.stencilStoreOp = depthStencilTargetInfo->stencil_store_op;
     }
 
+    SDL_LockMutex(renderer->renderPassFetchLock);
+
     bool result = SDL_FindInHashTable(
         renderer->renderPassHashTable,
         (const void *)&key,
         (const void **)&renderPassWrapper);
 
     if (result) {
+        SDL_UnlockMutex(renderer->renderPassFetchLock);
         return renderPassWrapper->handle;
     }
 
@@ -7050,6 +7055,7 @@ static VkRenderPass VULKAN_INTERNAL_FetchRenderPass(
         depthStencilTargetInfo);
 
     if (renderPassHandle == VK_NULL_HANDLE) {
+        SDL_UnlockMutex(renderer->renderPassFetchLock);
         return VK_NULL_HANDLE;
     }
 
@@ -7065,6 +7071,8 @@ static VkRenderPass VULKAN_INTERNAL_FetchRenderPass(
         (const void *)allocedKey,
         (const void *)renderPassWrapper, true);
 
+    SDL_UnlockMutex(renderer->renderPassFetchLock);
+
     return renderPassHandle;
 }
 
@@ -7133,9 +7141,8 @@ static VulkanFramebuffer *VULKAN_INTERNAL_FetchFramebuffer(
         (const void *)&key,
         (const void **)&vulkanFramebuffer);
 
-    SDL_UnlockMutex(renderer->framebufferFetchLock);
-
     if (findResult) {
+        SDL_UnlockMutex(renderer->framebufferFetchLock);
         return vulkanFramebuffer;
     }
 
@@ -7203,19 +7210,18 @@ static VulkanFramebuffer *VULKAN_INTERNAL_FetchFramebuffer(
         FramebufferHashTableKey *allocedKey = SDL_malloc(sizeof(FramebufferHashTableKey));
         SDL_memcpy(allocedKey, &key, sizeof(FramebufferHashTableKey));
 
-        SDL_LockMutex(renderer->framebufferFetchLock);
-
         SDL_InsertIntoHashTable(
             renderer->framebufferHashTable,
             (const void *)allocedKey,
             (const void *)vulkanFramebuffer, true);
 
-        SDL_UnlockMutex(renderer->framebufferFetchLock);
     } else {
         SDL_free(vulkanFramebuffer);
+        SDL_UnlockMutex(renderer->framebufferFetchLock);
         CHECK_VULKAN_ERROR_AND_RETURN(result, vkCreateFramebuffer, NULL);
     }
 
+    SDL_UnlockMutex(renderer->framebufferFetchLock);
     return vulkanFramebuffer;
 }
 
@@ -11607,6 +11613,7 @@ static SDL_GPUDevice *VULKAN_CreateDevice(bool debugMode, bool preferLowPower, S
     renderer->submitLock = SDL_CreateMutex();
     renderer->acquireCommandBufferLock = SDL_CreateMutex();
     renderer->acquireUniformBufferLock = SDL_CreateMutex();
+    renderer->renderPassFetchLock = SDL_CreateMutex();
     renderer->framebufferFetchLock = SDL_CreateMutex();
     renderer->windowLock = SDL_CreateMutex();
 
@@ -11668,7 +11675,7 @@ static SDL_GPUDevice *VULKAN_CreateDevice(bool debugMode, bool preferLowPower, S
 
     renderer->renderPassHashTable = SDL_CreateHashTable(
         0,  // !!! FIXME: a real guess here, for a _minimum_ if not a maximum, could be useful.
-        true,  // thread-safe
+        false,  // manually synchronized due to timing
         VULKAN_INTERNAL_RenderPassHashFunction,
         VULKAN_INTERNAL_RenderPassHashKeyMatch,
         VULKAN_INTERNAL_RenderPassHashDestroy,