diff --git a/tests/unit/test_umma_qk.cu b/tests/unit/test_umma_qk.cu
index 5544d03b..ab220b04 100644
--- a/tests/unit/test_umma_qk.cu
+++ b/tests/unit/test_umma_qk.cu
@@ -32,7 +32,8 @@ test_umma_qk_hd16(
     extern __shared__ char sbuf[];
     uint32_t* sTmemBase = (uint32_t*)sbuf;
     bf16_t* sQ = (bf16_t*)(((uintptr_t)(sbuf + 4) + 15) & ~(uintptr_t)15);
-    bf16_t* sK = sQ + 128 * 16;
+    // Add 8KB padding after sQ to prevent MMA from reading into sK
+    bf16_t* sK = sQ + 128 * 16 + 4096;  // 4096 BF16 = 8KB padding
     float* sQ_row = (float*)(sK + 128 * 16);
 
     for (int d = tid; d < 16; d += NTHREADS)
@@ -54,9 +55,9 @@ test_umma_qk_hd16(
     // Descriptors
     uint32_t sQ_smem = __cvta_generic_to_shared(sQ);
     uint32_t sK_smem = __cvta_generic_to_shared(sK);
-    uint64_t desc_q = make_umma_desc_kmajor_none(sQ_smem, 64);  // Try M=64
-    uint64_t desc_k = make_umma_desc_kmajor_none(sK_smem, 64);  // Try M=64
-    uint32_t idesc = make_idesc(64, 128);  // M=64, N=128
+    uint64_t desc_q = make_umma_desc_kmajor_none(sQ_smem, 128);
+    uint64_t desc_k = make_umma_desc_kmajor_none(sK_smem, 128);
+    uint32_t idesc = make_idesc(128, 128);  // M=128, N=128
 
     // Verify SMEM Q and K by reading back row 0
     if (tid == 0) {
@@ -133,7 +134,7 @@ int main() {
     cudaMemset(d_s_out, 0, 256 * sizeof(float));
     cudaMemset(d_s_scalar, 0, SK * sizeof(float));
 
-    int smem = (4 + 16 + 128*16*2 + 128*16*2 + 16*4 + 256 + 127) & ~127;
+    int smem = (4 + 16 + 128*16*2 + 4096*2 + 128*16*2 + 16*4 + 256 + 127) & ~127;
     test_umma_qk_hd16<<<1, NTHREADS, smem>>>(d_q, d_k, d_s_out, d_s_scalar, SCALE);
 
     cudaError_t err = cudaDeviceSynchronize();