From 7af18a2aa8b1cb7051e92cd268e583780c701eaf Mon Sep 17 00:00:00 2001
From: Zephyron <zephyron@citron-emu.org>
Date: Wed, 21 Jan 2026 18:53:40 +1000
Subject: [PATCH] fix(texture_cache): handle unmapped memory regions gracefully

- Skip upload for unmapped texture regions with zeroed staging buffer

- Add safety checks in UploadImageContents for unmapped GPU memory

- Prevents GPU errors from invalid memory access during texture upload
---
 src/video_core/texture_cache/texture_cache.h | 17 +++++++++++++++++
 src/video_core/texture_cache/util.cpp        | 15 ++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/video_core/texture_cache/texture_cache.h b/src/video_core/texture_cache/texture_cache.h
index be4c3c948..d038ec3a7 100644
--- a/src/video_core/texture_cache/texture_cache.h
+++ b/src/video_core/texture_cache/texture_cache.h
@@ -4,10 +4,12 @@
 
 #pragma once
 
+#include <cstring>
 #include <unordered_set>
 #include <boost/container/small_vector.hpp>
 
 #include "common/alignment.h"
+#include "common/logging/log.h"
 #include "common/settings.h"
 #include "video_core/control/channel_state.h"
 #include "video_core/dirty_flags.h"
@@ -1076,6 +1078,21 @@ void TextureCache<P>::UploadImageContents(Image& image, StagingBuffer& staging)
     const std::span<u8> mapped_span = staging.mapped_span;
     const GPUVAddr gpu_addr = image.gpu_addr;
 
+    // FIXED: Check if GPU memory is mapped before reading to prevent device loss
+    // This fixes Switch Sports and other games that crash due to unmapped GPU memory reads
+    // Similar to Ryujinx's GetSpanMapped() approach - gracefully handle unmapped memory
+    if (!gpu_memory->IsFullyMappedRange(gpu_addr, image.guest_size_bytes)) {
+        LOG_WARNING(HW_GPU,
+                    "Texture upload from unmapped GPU memory at 0x{:016X} (size: {} KB). "
+                    "Zeroing staging buffer and skipping upload.",
+                    gpu_addr, image.guest_size_bytes / 1024);
+        // Zero the staging buffer to ensure no garbage data is used if something reads it
+        std::memset(mapped_span.data(), 0, mapped_span.size_bytes());
+        // Skip the upload - trying to upload with invalid copy parameters can crash
+        // The image will use its previous state or be initialized to a safe default
+        return;
+    }
+
     if (True(image.flags & ImageFlagBits::AcceleratedUpload)) {
         gpu_memory->ReadBlock(gpu_addr, mapped_span.data(), mapped_span.size_bytes(),
                               VideoCommon::CacheType::NoTextureCache);
diff --git a/src/video_core/texture_cache/util.cpp b/src/video_core/texture_cache/util.cpp
index cf31dc70d..dff3458c8 100644
--- a/src/video_core/texture_cache/util.cpp
+++ b/src/video_core/texture_cache/util.cpp
@@ -9,6 +9,7 @@
 
 #include <algorithm>
 #include <array>
+#include <cstring>
 #include <numeric>
 #include <optional>
 #include <span>
@@ -19,6 +20,7 @@
 #include "common/bit_util.h"
 #include "common/common_types.h"
 #include "common/div_ceil.h"
+#include "common/logging/log.h"
 #include "common/scratch_buffer.h"
 #include "common/settings.h"
 #include "video_core/compatible_formats.h"
@@ -858,7 +860,18 @@ boost::container::small_vector<BufferImageCopy, 16> UnswizzleImage(Tegra::Memory
 
     if (info.type == ImageType::Linear) {
         ASSERT(output.size_bytes() >= guest_size_bytes);
-        gpu_memory.ReadBlockUnsafe(gpu_addr, output.data(), guest_size_bytes);
+
+        // FIXED: Validate GPU memory is mapped before reading to prevent device loss
+        // This fixes Switch Sports crash - similar to Ryujinx's GetSpanMapped() approach
+        if (!gpu_memory.IsFullyMappedRange(gpu_addr, guest_size_bytes)) {
+            LOG_WARNING(HW_GPU,
+                        "Linear texture read from unmapped GPU memory at 0x{:016X} (size: {} KB). "
+                        "Zeroing texture data to prevent device loss.",
+                        gpu_addr, guest_size_bytes / 1024);
+            std::memset(output.data(), 0, guest_size_bytes);
+        } else {
+            gpu_memory.ReadBlockUnsafe(gpu_addr, output.data(), guest_size_bytes);
+        }
 
         ASSERT((info.pitch >> bpp_log2) << bpp_log2 == info.pitch);
         return {{