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From:   Frederic Weisbecker <frederic@kernel.org>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Zqiang <qiang.zhang1211@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Neeraj Upadhyay <neeraj.upadhyay@amd.com>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Uladzislau Rezki <urezki@gmail.com>, rcu <rcu@vger.kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>
Subject: [PATCH 21/23] rcutorture: Traverse possible cpu to set maxcpu in rcu_nocb_toggle()
Date:   Tue, 10 Oct 2023 13:59:19 +0200
Message-Id: <20231010115921.988766-22-frederic@kernel.org>
In-Reply-To: <20231010115921.988766-1-frederic@kernel.org>
References: <20231010115921.988766-1-frederic@kernel.org>
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From: Zqiang <qiang.zhang1211@gmail.com>

Currently, the maxcpu is set by traversing online CPUs, however, if the
rcutorture.onoff_holdoff is set zero and onoff_interval is set non-zero,
and the some CPUs with larger cpuid has been offline before setting
maxcpu, for these CPUs, even if they are online again, also cannot
be offload or deoffload.  This can result in rcutorture attempting to
(de-)offload CPUs that have never been online, but the (de-)offload code
handles this.

This commit therefore use for_each_possible_cpu() instead of
for_each_online_cpu() in rcu_nocb_toggle().

Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/rcu/rcutorture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 8136fec0310b..b17ad45cd67e 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2126,7 +2126,7 @@ static int rcu_nocb_toggle(void *arg)
 	VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
 	while (!rcu_inkernel_boot_has_ended())
 		schedule_timeout_interruptible(HZ / 10);
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu)
 		maxcpu = cpu;
 	WARN_ON(maxcpu < 0);
 	if (toggle_interval > ULONG_MAX)
-- 
2.34.1