diff --git a/cpp/tensorrt_llm/kernels/topkLastDim.cu b/cpp/tensorrt_llm/kernels/topkLastDim.cu
index 3371ab4a0f2a..74e2838822c6 100644
--- a/cpp/tensorrt_llm/kernels/topkLastDim.cu
+++ b/cpp/tensorrt_llm/kernels/topkLastDim.cu
@@ -1275,8 +1275,8 @@ void standalone_stable_radix_topk_(void* buf, size_t& buf_size, T const* in, Idx
             sort_in = static_cast<decltype(sort_in)>(aligned_pointers[9]);
             sort_in_idx = static_cast<decltype(sort_in_idx)>(aligned_pointers[10]);
         }
-        cudaMemsetAsync(
-            buf, 0, static_cast<char*>(aligned_pointers[2]) - static_cast<char*>(aligned_pointers[0]), stream);
+        cudaMemsetAsync(aligned_pointers[0], 0,
+            static_cast<char*>(aligned_pointers[2]) - static_cast<char*>(aligned_pointers[0]), stream);
     }
 
     T const* in_buf = nullptr;