linux-kernel - [PATCH rcu 1/6] rcu/tasks: Check processor-ID assumptions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240802003426.4134196-1-paulmck@kernel.org>
Date: Thu,  1 Aug 2024 17:34:21 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: rcu@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	kernel-team@...a.com,
	rostedt@...dmis.org,
	"Paul E. McKenney" <paulmck@...nel.org>
Subject: [PATCH rcu 1/6] rcu/tasks: Check processor-ID assumptions

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@...nel.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