6.6-stable review patch. If anyone has any objections, please let me know.
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From: Frederic Weisbecker frederic@kernel.org
[ Upstream commit a80712b9cc7e57830260ec5e1feb9cdb59e1da2f ]
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 Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Frederic Weisbecker frederic@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/rcu/tasks.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index b5dc1e5d78c83..65e000ca332cc 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -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++; }