diff --git a/src/webgpu/shader/execution/expression/call/builtin/texture_utils.ts b/src/webgpu/shader/execution/expression/call/builtin/texture_utils.ts
index 2e4123c6cfeb..ba8a58ae861c 100644
--- a/src/webgpu/shader/execution/expression/call/builtin/texture_utils.ts
+++ b/src/webgpu/shader/execution/expression/call/builtin/texture_utils.ts
@@ -522,7 +522,7 @@ export async function queryMipLevelMixWeightsForDevice(t: GPUTest, stage: Shader
       pass.setBindGroup(0, createBindGroup(pipeline));
       pass.dispatchWorkgroups(kMipLevelWeightSteps + 1);
       pass.end();
-      encoder.copyBufferToBuffer(storageBuffer, 0, resultBuffer, 0, resultBuffer.size);
+      encoder.copyBufferToBuffer(storageBuffer, 0, resultBuffer, 0, storageBuffer.size);
       break;
     }
     case 'fragment': {