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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, "Paul E. McKenney" <paulmck@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 283/779] rcutorture: Dont cpuhp_remove_state() if cpuhp_setup_state() failed
Date:   Mon, 15 Aug 2022 19:58:47 +0200
Message-Id: <20220815180349.403405923@linuxfoundation.org>
In-Reply-To: <20220815180337.130757997@linuxfoundation.org>
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From: Paul E. McKenney <paulmck@kernel.org>

[ Upstream commit fd13fe16db0d82612b260640f4e26f6d9d1e11fd ]

Currently, in CONFIG_RCU_BOOST kernels, if the rcu_torture_init()
function's call to cpuhp_setup_state() fails, rcu_torture_cleanup()
gamely passes nonsense to cpuhp_remove_state().  This results in
strange and misleading splats.  This commit therefore ensures that if
the rcu_torture_init() function's call to cpuhp_setup_state() fails,
rcu_torture_cleanup() avoids invoking cpuhp_remove_state().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/rcu/rcutorture.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index c1b36c52e896..3262330d1679 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2848,7 +2848,7 @@ rcu_torture_cleanup(void)
 		 rcutorture_seq_diff(gp_seq, start_gp_seq));
 	torture_stop_kthread(rcu_torture_stats, stats_task);
 	torture_stop_kthread(rcu_torture_fqs, fqs_task);
-	if (rcu_torture_can_boost())
+	if (rcu_torture_can_boost() && rcutor_hp >= 0)
 		cpuhp_remove_state(rcutor_hp);
 
 	/*
@@ -3161,9 +3161,9 @@ rcu_torture_init(void)
 		firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
 					     rcutorture_booster_init,
 					     rcutorture_booster_cleanup);
+		rcutor_hp = firsterr;
 		if (torture_init_error(firsterr))
 			goto unwind;
-		rcutor_hp = firsterr;
 
 		// Testing RCU priority boosting requires rcutorture do
 		// some serious abuse.  Counter this by running ksoftirqd
-- 
2.35.1