diff --git a/tests/unit/test_fmha_smem_p.cu b/tests/unit/test_fmha_smem_p.cu
index 001836d7..87368f76 100644
--- a/tests/unit/test_fmha_smem_p.cu
+++ b/tests/unit/test_fmha_smem_p.cu
@@ -190,6 +190,7 @@ int main() {
 
     cudaError_t launch_err = cudaGetLastError();
     if (launch_err != cudaSuccess) { printf("LAUNCH ERROR: %s\n", cudaGetErrorString(launch_err)); return 1; }
+    cudaError_t err = cudaDeviceSynchronize();
     if (err != cudaSuccess) { printf("CUDA ERROR: %s\n", cudaGetErrorString(err)); return 1; }
 
     cudaMemcpy(h_o, d_o, HD*sizeof(bf16_t), cudaMemcpyDeviceToHost);