fix: force contiguous on SF tensors before C++ call

deep_gemm/mega/__init__.py

@@ -319,6 +319,15 @@ def fp8_nvfp4_mega_moe(y: torch.Tensor,
     """
     l1_w, l1_w_sf = l1_weights
     l2_w, l2_w_sf = l2_weights
+
+    # Force contiguous on SF tensors — non-contiguous SF breaks TMA descriptors
+    for name, t in [("l1_w_sf", l1_w_sf), ("l2_w_sf", l2_w_sf)]:
+        if not t.is_contiguous():
+            print(f"[contig-fix] {name}: was NOT contiguous, forcing", flush=True)
+            # (assign back to correct variable)
+    l1_w_sf = l1_w_sf.contiguous()
+    l2_w_sf = l2_w_sf.contiguous()
+
     for name, t in [("l1_w", l1_w), ("l1_w_sf", l1_w_sf),
                      ("l2_w", l2_w), ("l2_w_sf", l2_w_sf)]:
         print(f"[debug] {name}: dtype={t.dtype} shape={tuple(t.shape)} contig={t.is_contiguous()}", flush=True)
@@ -330,7 +339,7 @@ def fp8_nvfp4_mega_moe(y: torch.Tensor,
 
     _C.fp8_nvfp4_mega_moe(
         y,
-        l1_weights, l2_weights,
+        (l1_w, l1_w_sf), (l2_w, l2_w_sf),
         cumulative_local_expert_recv_stats,
         sym_buffer.buffer,
         sym_buffer.handle.buffer_ptrs, sym_buffer.group.rank(),