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From: Daniil Dulov <d.dulov@aladdin.ru>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, <stable@vger.kernel.org>
CC: Daniil Dulov <d.dulov@aladdin.ru>, Davidlohr Bueso <dave@stgolabs.net>,
	"Paul E. McKenney" <paulmck@kernel.org>, Josh Triplett
	<josh@joshtriplett.org>, Steven Rostedt <rostedt@goodmis.org>, Mathieu
 Desnoyers <mathieu.desnoyers@efficios.com>, Lai Jiangshan
	<jiangshanlai@gmail.com>, Joel Fernandes <joel@joelfernandes.org>,
	<linux-kernel@vger.kernel.org>, <rcu@vger.kernel.org>,
	<lvc-project@linuxtesting.org>, David Vernet <void@manifault.com>
Subject: [PATCH 5.15 1/1] rcutorture: Add missing return and use __func__ in warning
Date: Tue, 27 Feb 2024 13:22:22 +0300
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From: David Vernet <void@manifault.com>

commit 80dcee695143255261f30c7cc2a041ba413717a4 upstream.

The rcutorture module has an rcu_torture_writer task that repeatedly
performs writes, synchronizations, and deletes. There is a corner-case
check in rcu_torture_writer() wherein if nsynctypes is 0, a warning is
issued and the task waits to be stopped via a call to
torture_kthread_stopping() rather than performing any work.

There should be a return statement following this call to
torture_kthread_stopping(), as the intention with issuing the call to
torture_kthread_stopping() in the first place is to avoid the
rcu_torture_writer task from performing any work. Some of the work may even
be dangerous to perform, such as potentially causing a #DE due to
nsynctypes being used in a modulo operator when querying for sync updates
to issue.

This patch adds the missing return call.  As a bonus, it also fixes a
checkpatch warning that was emitted due to the WARN_ONCE() call using the
name of the function rather than __func__.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Daniil Dulov <d.dulov@aladdin.ru>
---
 kernel/rcu/rcutorture.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index d820ef615475..a76399bd43b9 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1165,7 +1165,7 @@ rcu_torture_writer(void *arg)
 			 " GP expediting controlled from boot/sysfs for %s.\n",
 			 torture_type, cur_ops->name);
 	if (WARN_ONCE(nsynctypes == 0,
-		      "rcu_torture_writer: No update-side primitives.\n")) {
+		      "%s: No update-side primitives.\n", __func__)) {
 		/*
 		 * No updates primitives, so don't try updating.
 		 * The resulting test won't be testing much, hence the
@@ -1173,6 +1173,7 @@ rcu_torture_writer(void *arg)
 		 */
 		rcu_torture_writer_state = RTWS_STOPPING;
 		torture_kthread_stopping("rcu_torture_writer");
+		return 0;
 	}
 
 	do {
-- 
2.25.1