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 rcu 1/6] rcu/tasks: Check processor-ID assumptions
Date: Thu, 1 Aug 2024 17:34:21 -0700 [thread overview]
Message-ID: <20240802003426.4134196-1-paulmck@kernel.org> (raw)
In-Reply-To: <41c68c6b-2c55-4c2d-ab70-f2a5b38eb374@paulmck-laptop>
The current mapping of smp_processor_id() to a CPU processing Tasks-RCU
callbacks makes some assumptions about layout. This commit therefore
adds a WARN_ON() to check these assumptions.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tasks.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index b6fcf744af75d..d473846a572aa 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -355,6 +355,7 @@ static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func,
rcu_read_lock();
ideal_cpu = smp_processor_id() >> READ_ONCE(rtp->percpu_enqueue_shift);
chosen_cpu = cpumask_next(ideal_cpu - 1, cpu_possible_mask);
+ WARN_ON_ONCE(chosen_cpu >= nr_cpu_ids);
rtpcp = per_cpu_ptr(rtp->rtpcpu, chosen_cpu);
if (!raw_spin_trylock_rcu_node(rtpcp)) { // irqs already disabled.
raw_spin_lock_rcu_node(rtpcp); // irqs already disabled.
--
2.40.1
next prev parent reply other threads:[~2024-08-02 0:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-02 0:34 [PATCH rcu 0/6] Add RCU Tasks diagnostics and documentation Paul E. McKenney
2024-08-02 0:34 ` Paul E. McKenney [this message]
2024-08-14 12:16 ` [PATCH rcu 1/6] rcu/tasks: Check processor-ID assumptions Neeraj Upadhyay
2024-08-14 16:13 ` Paul E. McKenney
2024-08-02 0:34 ` [PATCH rcu 2/6] rcu/tasks: Update rtp->tasks_gp_seq comment Paul E. McKenney
2024-08-02 0:34 ` [PATCH rcu 3/6] rcu: Provide rcu_barrier_cb_is_done() to check rcu_barrier() CBs Paul E. McKenney
2024-08-02 0:34 ` [PATCH rcu 4/6] rcu/tasks: Mark callbacks not currently participating in barrier operation Paul E. McKenney
2024-08-02 0:34 ` [PATCH rcu 5/6] rcu/tasks: Add detailed grace-period and barrier diagnostics Paul E. McKenney
2024-08-02 0:34 ` [PATCH rcu 6/6] rcu/tasks: Add rcu_barrier_tasks*() start time to diagnostics Paul E. McKenney
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