Fix memory errors in buffer_cache

src/video_core/buffer_cache/buffer_cache.h

@@ -1568,20 +1568,37 @@ void BufferCache<P>::ImmediateUploadMemory([[maybe_unused]] Buffer& buffer,
 }
 
 template <class P>
-void BufferCache<P>::MappedUploadMemory([[maybe_unused]] Buffer& buffer,
-                                        [[maybe_unused]] u64 total_size_bytes,
-                                        [[maybe_unused]] std::span<BufferCopy> copies) {
+void BufferCache<P>::MappedUploadMemory(Buffer& buffer,
+                                        u64 total_size_bytes,
+                                        std::span<BufferCopy> copies) {
     if constexpr (USE_MEMORY_MAPS) {
         auto upload_staging = runtime.UploadStagingBuffer(total_size_bytes);
         const std::span<u8> staging_pointer = upload_staging.mapped_span;
+
+        if (staging_pointer.size() < total_size_bytes) {
+            LOG_DEBUG(HW_GPU, "Staging buffer too small for total size bytes");
+            return;
+        }
+
         for (BufferCopy& copy : copies) {
+            if (copy.src_offset + copy.size > staging_pointer.size()) {
+                LOG_ERROR(HW_GPU, "Copy exceeds staging buffer bounds (src_offset: {}, size: {})", copy.src_offset, copy.size);
+                return;
+            }
+
             u8* const src_pointer = staging_pointer.data() + copy.src_offset;
+
+            if (copy.dst_offset + copy.size > buffer.Size()) {
+                LOG_ERROR(HW_GPU, "Copy exceeds buffer bounds (dst_offset: {}, size: {})", copy.dst_offset, copy.size);
+                return;
+            }
+
             const DAddr device_addr = buffer.CpuAddr() + copy.dst_offset;
             device_memory.ReadBlockUnsafe(device_addr, src_pointer, copy.size);
 
-            // Apply the staging offset
             copy.src_offset += upload_staging.offset;
         }
+
         const bool can_reorder = runtime.CanReorderUpload(buffer, copies);
         runtime.CopyBuffer(buffer, upload_staging.buffer, copies, true, can_reorder);
     }