From 017d9cc0d612f2d5c11ffcd2f8ea18075caa5e11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?F=C3=A1bio=20Mestre?= <fabio.mestre@codeplay.com>
Date: Wed, 18 Dec 2024 17:57:59 +0000
Subject: [PATCH] Move event resets from SignalCommandList to
 ComputeCommandList

Moves the call to event reset for the WaitEvent and AllResetEvent
to the ComputeCommandList.

This fixes a potential race condition where, if the SignalCommandList
executes before the ComputeCommandList, the WaitEvent could be reset
before the ComputeCommandList can wait on it and, consequently,
create a deadlock.
---
 source/adapters/level_zero/command_buffer.cpp | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/source/adapters/level_zero/command_buffer.cpp b/source/adapters/level_zero/command_buffer.cpp
index b96aeeede9..e678deb3e5 100644
--- a/source/adapters/level_zero/command_buffer.cpp
+++ b/source/adapters/level_zero/command_buffer.cpp
@@ -1683,10 +1683,15 @@ ur_result_t enqueueWaitEventPath(ur_exp_command_buffer_handle_t CommandBuffer,
         (ZeCopyCommandQueue, 1, &CommandBuffer->ZeCopyCommandList, nullptr));
   }
 
+  ZE2UR_CALL(zeCommandListAppendBarrier,
+             (SignalCommandList->first, nullptr, 1,
+              &(CommandBuffer->ExecutionFinishedEvent->ZeEvent)));
+
   // Reset the wait-event for the UR command-buffer that is signaled when its
   // submission dependencies have been satisfied.
   ZE2UR_CALL(zeCommandListAppendEventReset,
              (SignalCommandList->first, CommandBuffer->WaitEvent->ZeEvent));
+
   // Reset the all-reset-event for the UR command-buffer that is signaled when
   // all events of the main command-list have been reset.
   ZE2UR_CALL(zeCommandListAppendEventReset,
@@ -1694,14 +1699,12 @@ ur_result_t enqueueWaitEventPath(ur_exp_command_buffer_handle_t CommandBuffer,
 
   if (DoProfiling) {
     UR_CALL(appendProfilingQueries(CommandBuffer, SignalCommandList->first,
-                                   *Event,
-                                   CommandBuffer->ExecutionFinishedEvent));
-  } else {
-    ZE2UR_CALL(zeCommandListAppendBarrier,
-               (SignalCommandList->first, (*Event)->ZeEvent, 1,
-                &(CommandBuffer->ExecutionFinishedEvent->ZeEvent)));
+                                   nullptr, nullptr));
   }
 
+  ZE2UR_CALL(zeCommandListAppendBarrier,
+             (SignalCommandList->first, (*Event)->ZeEvent, 0, nullptr));
+
   UR_CALL(Queue->executeCommandList(SignalCommandList, false /*IsBlocking*/,
                                     false /*OKToBatchCommand*/));