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From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com,
	rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH v2 12/13] rcutorture: Announce declining to forward-progress test
Date: Thu, 30 Jul 2026 18:07:18 -0700	[thread overview]
Message-ID: <20260731010719.3531912-12-paulmck@kernel.org> (raw)
In-Reply-To: <d1db6e52-06c2-401d-b6fe-85aa588196d8@paulmck-laptop>

Currently, rcu_torture_fwd_prog_cr() announces function entry,
but silently exits if rcu_fwd_emergency_stop is set or if there is no
->call() function available.  This could cause confusion, leading people
to believe that rcu_torture_fwd_prog_cr() is on the job when it is not.
This commit therefore also announces the early exits from this function.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/rcutorture.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 9180016d87c0ce..46d97055c2fcde 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -3623,13 +3623,17 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
 	unsigned long stopat;
 	unsigned long stoppedat;
 
-	pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
-	if (READ_ONCE(rcu_fwd_emergency_stop))
+	if (READ_ONCE(rcu_fwd_emergency_stop)) {
+		pr_alert("%s: Emergency stop, so no forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
 		return; /* Get out of the way quickly, no GP wait! */
-	if (!cur_ops->call)
+	}
+	if (!cur_ops->call) {
+		pr_alert("%s: No ->call(), so no forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
 		return; /* Can't do call_rcu() fwd prog without ->call. */
+	}
 
 	/* Loop continuously posting RCU callbacks. */
+	pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
 	atomic_inc(&rcu_fwd_cb_nodelay);
 	cur_ops->sync(); /* Later readers see above write. */
 	WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
-- 
2.40.1


  parent reply	other threads:[~2026-07-31  1:07 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-16  0:25 [PATCH 0/11] RCU torture-test updates for v7.3 Paul E. McKenney
2026-07-16  0:25 ` [PATCH 01/11] rcutorture: Abstract reader-segment dump into rcu_torture_dump_read_segs() Paul E. McKenney
2026-07-16  0:25 ` [PATCH 02/11] rcutorture: Check for immediate deboosting at reader end Paul E. McKenney
2026-07-16  0:25 ` [PATCH 03/11] rcutorture: Make srcu_read_delay() check for disabled interrupts Paul E. McKenney
2026-07-16  0:25 ` [PATCH 04/11] rcutorture: Test RCU readers from hardware interrupt handlers Paul E. McKenney
2026-07-16  0:25 ` [PATCH 05/11] rcutorture: Use cpumask_next_wrap() in rcu_torture_preempt() Paul E. McKenney
2026-07-16  0:25 ` [PATCH 06/11] rcutorture: Use task_state_to_char() for task-state reporting Paul E. McKenney
2026-07-16  0:25 ` [PATCH 07/11] rcutorture: Add nwriters module parameter Paul E. McKenney
2026-07-16  0:25 ` [PATCH 08/11] rcutorture: Add a stall_only " Paul E. McKenney
2026-07-16  0:25 ` [PATCH 09/11] rcutorture: Test RCU Tasks Trace GP implying RCU GP Paul E. McKenney
2026-07-16  0:25 ` [PATCH 10/11] rcutorture: Make RCU Tasks Trace track Reader Batches Paul E. McKenney
2026-07-16  0:25 ` [PATCH 11/11] rcutorture: Use this_cpu_inc() for rcu_torture_count[] and rcu_torture_batch[] Paul E. McKenney
2026-07-31  1:07 ` [PATCH v2 0/13] RCU torture-test updates for v7.3 Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 01/13] rcutorture: Abstract reader-segment dump into rcu_torture_dump_read_segs() Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 02/13] rcutorture: Check for immediate deboosting at reader end Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 03/13] rcutorture: Test RCU readers from hardware interrupt handlers Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 04/13] rcutorture: Use cpumask_next_wrap() in rcu_torture_preempt() Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 05/13] rcutorture: Use task_state_to_char() for task-state reporting Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 06/13] rcutorture: Add nwriters module parameter Paul E. McKenney
2026-07-31  8:22     ` Breno Leitao
2026-07-31  1:07   ` [PATCH v2 07/13] rcutorture: Add a stall_only " Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 08/13] rcutorture: Test RCU Tasks Trace GP implying RCU GP Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 09/13] rcutorture: Make RCU Tasks Trace track Reader Batches Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 10/13] rcutorture: Use this_cpu_inc() for rcu_torture_count[] and rcu_torture_batch[] Paul E. McKenney
2026-07-31  1:07   ` [PATCH v2 11/13] torture: Don't leak shuffle_tmp_mask when shuffler kthread fails to start Paul E. McKenney
2026-07-31  1:07   ` Paul E. McKenney [this message]
2026-07-31  1:07   ` [PATCH v2 13/13] rcutorture: Make {,s}rcu_read_delay() better handle forward-progress testing Paul E. McKenney

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