[Openmp-commits] [PATCH] D141979: [OpenMP] Fix inconsistent task state if hot team is not used

Shilei Tian via Phabricator via Openmp-commits openmp-commits at lists.llvm.org
Tue Jan 17 16:53:06 PST 2023

tianshilei1992 created this revision.
tianshilei1992 added reviewers: jdoerfert, hbae, AndreyChurbanov, jlpeyton.
Herald added subscribers: guansong, yaxunl.
Herald added a project: All.
tianshilei1992 requested review of this revision.
Herald added subscribers: openmp-commits, sstefan1.
Herald added a project: OpenMP.

This patch fixes the inconsistent task state when hot team is not used.
When the primary thread executes `__kmp_join_call`, it calls `__kmp_free_team`,
where worker threads will get destroyed if not using hot team. The destroy of
worker threads also reset their task state. However, the primary thread's is not
reset. When the next parallel region is encountered, in `__kmp_task_team_sync`,
the task state of thread will be flipped. Since the state of primary thread is not
reset, it is still 1, but all the worker threads will be 0, this leads to the
inconsistent task state, causing those threads are using completely different
task team.

Fix #59190.

  rG LLVM Github Monorepo



Index: openmp/runtime/src/kmp_runtime.cpp
--- openmp/runtime/src/kmp_runtime.cpp
+++ openmp/runtime/src/kmp_runtime.cpp
@@ -2673,6 +2673,12 @@
       master_th->th.th_task_state =
+    } else if (team != root->r.r_hot_team) {
+      // Reset the task state of primary thread if we are not hot team because
+      // in this case all the worker threads will be free, and their task state
+      // will be reset. If not reset the primary's, the task state will be
+      // inconsistent.
+      master_th->th.th_task_state = 0;
     // Copy the task team from the parent team to the primary thread
     master_th->th.th_task_team =

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