diff mbox series

[3/4] rcu/tasks-trace: Handle new PF_IDLE semantics

Message ID 20231027144050.110601-4-frederic@kernel.org
State New
Headers
Series rcu: Fix PF_IDLE related issues v3 |

Commit Message

Frederic Weisbecker Oct. 27, 2023, 2:40 p.m. UTC 
  The commit:

	cff9b2332ab7 ("kernel/sched: Modify initial boot task idle setup")

has changed the semantics of what is to be considered an idle task in
such a way that the idle task of an offline CPU may not carry the
PF_IDLE flag anymore.

However RCU-tasks-trace tests the opposite assertion, still assuming
that idle tasks carry the PF_IDLE flag during their whole lifecycle.

Remove this assumption to avoid spurious warnings but keep the initial
test verifying that the idle task is the current task on any offline
CPU.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Fixes: cff9b2332ab7 ("kernel/sched: Modify initial boot task idle setup")
Suggested-by: Joel Fernandes <joel@joelfernandes.org>
Suggested-by: Paul E . McKenney" <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/rcu/tasks.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index a604f59aee0b..732ad5b39946 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1551,7 +1551,7 @@  static int trc_inspect_reader(struct task_struct *t, void *bhp_in)
 	} else {
 		// The task is not running, so C-language access is safe.
 		nesting = t->trc_reader_nesting;
-		WARN_ON_ONCE(ofl && task_curr(t) && !is_idle_task(t));
+		WARN_ON_ONCE(ofl && task_curr(t) && (t != idle_task(task_cpu(t))));
 		if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) && ofl)
 			n_heavy_reader_ofl_updates++;
 	}