From 3e8e258896b52415ceea33754b2eab722e349896 Mon Sep 17 00:00:00 2001
From: Igor Chorazewicz <igor.chorazewicz@intel.com>
Date: Tue, 6 May 2025 16:55:12 +0000
Subject: [PATCH 1/2] [SYCL][UR][L0] Fix urEnqueueEventsWait

The path for non-immediate command lists was incorrect.
queue->synchronize() was called without closing and executing
command lists leading to deadlock.

Fix this by add call to executeAllOpenCommandLists
---
 .../source/adapters/level_zero/event.cpp      | 40 +++++++++----------
 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/unified-runtime/source/adapters/level_zero/event.cpp b/unified-runtime/source/adapters/level_zero/event.cpp
index c53bfa1089100..807e3b8b2fa2c 100644
--- a/unified-runtime/source/adapters/level_zero/event.cpp
+++ b/unified-runtime/source/adapters/level_zero/event.cpp
@@ -114,35 +114,33 @@ ur_result_t urEnqueueEventsWait(
                                      false /*OKToBatchCommand*/);
   }
 
-  {
-    // If wait-list is empty, then this particular command should wait until
-    // all previous enqueued commands to the command-queue have completed.
-    //
-    // TODO: find a way to do that without blocking the host.
+  // If wait-list is empty, then this particular command should wait until
+  // all previous enqueued commands to the command-queue have completed.
+  //
+  // TODO: find a way to do that without blocking the host.
 
-    // Lock automatically releases when this goes out of scope.
-    std::scoped_lock<ur_shared_mutex> lock(Queue->Mutex);
+  // Lock automatically releases when this goes out of scope.
+  std::scoped_lock<ur_shared_mutex> lock(Queue->Mutex);
 
-    if (OutEvent) {
-      UR_CALL(createEventAndAssociateQueue(Queue, OutEvent,
-                                           UR_COMMAND_EVENTS_WAIT,
-                                           Queue->CommandListMap.end(), false,
-                                           /* IsInternal */ false));
-    }
+  if (OutEvent) {
+    UR_CALL(createEventAndAssociateQueue(Queue, OutEvent,
+                                         UR_COMMAND_EVENTS_WAIT,
+                                         Queue->CommandListMap.end(), false,
+                                         /* IsInternal */ false));
+  }
 
-    UR_CALL(Queue->synchronize());
+  UR_CALL(Queue->executeAllOpenCommandLists());
+  UR_CALL(Queue->synchronize());
 
-    if (OutEvent) {
-      Queue->LastCommandEvent = reinterpret_cast<ur_event_handle_t>(*OutEvent);
+  if (OutEvent) {
+    Queue->LastCommandEvent = reinterpret_cast<ur_event_handle_t>(*OutEvent);
 
-      if (!(*OutEvent)->CounterBasedEventsEnabled)
-        ZE2UR_CALL(zeEventHostSignal, ((*OutEvent)->ZeEvent));
-      (*OutEvent)->Completed = true;
-    }
+    if (!(*OutEvent)->CounterBasedEventsEnabled)
+      ZE2UR_CALL(zeEventHostSignal, ((*OutEvent)->ZeEvent));
+    (*OutEvent)->Completed = true;
   }
 
   if (!Queue->UsingImmCmdLists) {
-    std::unique_lock<ur_shared_mutex> Lock(Queue->Mutex);
     resetCommandLists(Queue);
   }
 

From 601b23ad97c880efdd4b4a0fa04897a9567fe890 Mon Sep 17 00:00:00 2001
From: Igor Chorazewicz <igor.chorazewicz@intel.com>
Date: Tue, 6 May 2025 20:07:04 +0000
Subject: [PATCH 2/2] Add test

---
 .../enqueue/urEnqueueEventsWait.cpp           | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/unified-runtime/test/conformance/enqueue/urEnqueueEventsWait.cpp b/unified-runtime/test/conformance/enqueue/urEnqueueEventsWait.cpp
index adbdf8d0e1065..1d9baa2f149c5 100644
--- a/unified-runtime/test/conformance/enqueue/urEnqueueEventsWait.cpp
+++ b/unified-runtime/test/conformance/enqueue/urEnqueueEventsWait.cpp
@@ -38,6 +38,33 @@ struct urEnqueueEventsWaitTest : uur::urMultiQueueTest {
 
 UUR_INSTANTIATE_DEVICE_TEST_SUITE(urEnqueueEventsWaitTest);
 
+TEST_P(urEnqueueEventsWaitTest, SuccessWithEmptyWaitList) {
+  void *ptr1, *ptr2;
+  size_t size = 1024;
+  size_t count = size / sizeof(int);
+
+  ASSERT_SUCCESS(
+      urUSMDeviceAlloc(context, device, nullptr, nullptr, size, &ptr1));
+  ASSERT_SUCCESS(
+      urUSMDeviceAlloc(context, device, nullptr, nullptr, size, &ptr2));
+
+  std::vector<int> input(count, 99);
+  std::vector<int> output(count, 0);
+
+  ASSERT_SUCCESS(urEnqueueUSMMemcpy(queue1, false, ptr1, input.data(), size, 0,
+                                    nullptr, nullptr));
+  ASSERT_SUCCESS(
+      urEnqueueUSMMemcpy(queue1, false, ptr2, ptr1, size, 0, nullptr, nullptr));
+  ASSERT_SUCCESS(urEnqueueUSMMemcpy(queue1, false, output.data(), ptr2, size, 0,
+                                    nullptr, nullptr));
+
+  ur_event_handle_t event;
+  ASSERT_SUCCESS(urEnqueueEventsWait(queue1, 0, nullptr, &event));
+  ASSERT_SUCCESS(urEventWait(1, &event));
+
+  ASSERT_EQ(input, output);
+}
+
 TEST_P(urEnqueueEventsWaitTest, Success) {
   UUR_KNOWN_FAILURE_ON(uur::LevelZero{}, uur::NativeCPU{});