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From: Joel Fernandes <joelagnelf@nvidia.com>
To: linux-kernel@vger.kernel.org, Davidlohr Bueso <dave@stgolabs.net>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
	Joel Fernandes <joelagnelf@nvidia.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Uladzislau Rezki <urezki@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Zqiang <qiang.zhang@linux.dev>
Cc: rcu@vger.kernel.org
Subject: [PATCH] rcutorture: Fix operator precedence bug in exp_current() invocation
Date: Mon, 22 Dec 2025 19:44:07 -0500	[thread overview]
Message-ID: <20251223004407.61147-1-joelagnelf@nvidia.com> (raw)

Fix incorrect operator precedence in the conditional that determines
when to call exp_current() during torture testing. The modulo
by 0xff appears to do nothing.

Fix by adding parentheses:

    !(torture_random(&rand) % 0xff)

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 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 82588ceed9da..9873a1d54c46 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1749,7 +1749,7 @@ rcu_torture_writer(void *arg)
 					ulo[i] = cur_ops->get_comp_state();
 				gp_snap = cur_ops->start_gp_poll();
 				rcu_torture_writer_state = RTWS_POLL_WAIT;
-				if (cur_ops->exp_current && !torture_random(&rand) % 0xff)
+				if (cur_ops->exp_current && !(torture_random(&rand) % 0xff))
 					cur_ops->exp_current();
 				while (!cur_ops->poll_gp_state(gp_snap)) {
 					gp_snap1 = cur_ops->get_gp_state();
@@ -1771,7 +1771,7 @@ rcu_torture_writer(void *arg)
 					cur_ops->get_comp_state_full(&rgo[i]);
 				cur_ops->start_gp_poll_full(&gp_snap_full);
 				rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
-				if (cur_ops->exp_current && !torture_random(&rand) % 0xff)
+				if (cur_ops->exp_current && !(torture_random(&rand) % 0xff))
 					cur_ops->exp_current();
 				while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
 					cur_ops->get_gp_state_full(&gp_snap1_full);
-- 
2.34.1


             reply	other threads:[~2025-12-23  0:44 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-23  0:44 Joel Fernandes [this message]
2025-12-23  1:12 ` [PATCH] rcutorture: Fix operator precedence bug in exp_current() invocation Paul E. McKenney
2025-12-23  1:24   ` Joel Fernandes
2025-12-23 16:37   ` Steven Rostedt
2025-12-23 17:22     ` Joel Fernandes
2025-12-23 17:28       ` Paul E. McKenney
2025-12-23 17:30         ` Joel Fernandes
2025-12-23 17:51           ` Paul E. McKenney
2025-12-23 20:54             ` Steven Rostedt
2025-12-23 23:50               ` Paul E. McKenney
2025-12-24 14:14                 ` Steven Rostedt
2025-12-25 18:43                   ` Paul E. McKenney
2025-12-24  0:50               ` Chris Mason

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