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rcu/tasks-trace: Handle new PF_IDLE semantics

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[ Upstream commit a80712b9cc ]

The commit:

	cff9b2332a ("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: cff9b2332a ("kernel/sched: Modify initial boot task idle setup")
Suggested-by: Joel Fernandes <joel@joelfernandes.org>
Suggested-by: "Paul E. McKenney" <paulmck@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Frederic Weisbecker 2023-10-27 16:40:49 +02:00 committed by Greg Kroah-Hartman
parent b3ffc11675
commit 5d1e4e5fd1
1 changed files with 1 additions and 1 deletions
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2
kernel/rcu/tasks.h
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@ -1548,7 +1548,7 @@ 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++;
}