linux-kernel - [PATCH AUTOSEL 5.10 043/217] rcuscale: Prevent hangs for invalid arguments

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Date:   Tue, 22 Dec 2020 21:13:32 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     "Paul E. McKenney" <paulmck@...nel.org>,
        Sasha Levin <sashal@...nel.org>, rcu@...r.kernel.org
Subject: [PATCH AUTOSEL 5.10 043/217] rcuscale: Prevent hangs for invalid arguments

From: "Paul E. McKenney" <paulmck@...nel.org>

[ Upstream commit 2f2214d43ccd27ac6d124287107c136a0f7c6053 ]

If an rcuscale torture-test run is given a bad kvm.sh argument, the
test will complain to the console, which is good.  What is bad is that
from the user's perspective, it will just hang for the time specified
by the --duration argument.  This commit therefore forces an immediate
kernel shutdown if a rcu_scale_init()-time error occurs, thus avoiding
the appearance of a hang.  It also forces a console splat in this case
to clearly indicate the presence of an error.

Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/rcu/rcuscale.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
index 2819b95479af9..c7b6529a0c39f 100644
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@ -772,7 +772,6 @@ rcu_scale_init(void)
 		for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
 			pr_cont(" %s", scale_ops[i]->name);
 		pr_cont("\n");
-		WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST));
 		firsterr = -EINVAL;
 		cur_ops = NULL;
 		goto unwind;
@@ -846,6 +845,10 @@ rcu_scale_init(void)
 unwind:
 	torture_init_end();
 	rcu_scale_cleanup();
+	if (shutdown) {
+		WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST));
+		kernel_power_off();
+	}
 	return firsterr;
 }
 
-- 
2.27.0