diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5a5b288..203fad8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -7,7 +7,7 @@ on:
   # to the main branch and tags.
   push:
     branches:
-      - "main"
+      - "*"
     tags:
       - "*"
 
diff --git a/ndonnx/_opset_extensions.py b/ndonnx/_opset_extensions.py
index df6e8cc..4675503 100644
--- a/ndonnx/_opset_extensions.py
+++ b/ndonnx/_opset_extensions.py
@@ -437,7 +437,25 @@ def clip(input: _CoreArray, min: _CoreArray, max: _CoreArray) -> _CoreArray:
 
 @eager_propagate
 def matmul(a: _CoreArray, b: _CoreArray) -> _CoreArray:
-    return _CoreArray(op.matmul(a.var, b.var))
+    # TODO(adityagoel4512): this requires an upstream patch in onnxruntime
+    # onnxruntime goes into UB with zero size inputs
+    (out,) = op.if_(
+        op.equal(op.size(a.var), op.const(0, dtype=np.int64)),
+        then_branch=lambda: [
+            op.const(
+                np.zeros(
+                    (),
+                    dtype=np.result_type(
+                        a.var.unwrap_tensor().dtype, b.var.unwrap_tensor().dtype
+                    ),
+                )
+            ),
+        ],
+        else_branch=lambda: [
+            op.matmul(a.var, b.var),
+        ],
+    )
+    return _CoreArray(out)
 
 
 @eager_propagate
diff --git a/xfails.txt b/xfails.txt
index fa73a81..e778add 100644
--- a/xfails.txt
+++ b/xfails.txt
@@ -44,7 +44,6 @@ array_api_tests/test_has_names.py::test_has_names[linalg-diagonal]
 array_api_tests/test_has_names.py::test_has_names[linalg-eigh]
 array_api_tests/test_has_names.py::test_has_names[linalg-eigvalsh]
 array_api_tests/test_has_names.py::test_has_names[linalg-inv]
-array_api_tests/test_has_names.py::test_has_names[linalg-matmul]
 array_api_tests/test_has_names.py::test_has_names[linalg-matrix_norm]
 array_api_tests/test_has_names.py::test_has_names[linalg-matrix_power]
 array_api_tests/test_has_names.py::test_has_names[linalg-matrix_rank]