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From: Bradley Morgan <include@grrlz.net>
To: "Rafael J . Wysocki" <rafael@kernel.org>
Cc: Thierry Reding <treding@nvidia.com>,
	Daniel Leznan <daniel.lezcano@kernel.org>,
	Thomas Gleixner <tglx@kernel.org>,
	Valentin Schneider <vschneid@redhat.com>,
	Rosen Penev <rosenp@gmail.com>,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 0/2] PM: cpu: Restore the RCU grace period to cpu_pm_unregister_notifier()
Date: Thu, 13 Aug 2026 07:43:41 +0000	[thread overview]
Message-ID: <20260813074343.26460-1-include@grrlz.net> (raw)

Since commit b2f6662ac08d ("PM: cpu: Make notifier chain use a
raw_spinlock_t") cpu_pm_unregister_notifier() no longer waits for an
RCU grace period, but cpu_pm_notify() still walks the chain with only
rcu_read_lock() held. A driver that frees its notifier block right
after unregistering can race with a concurrent walker.

Patch 1 moves the one caller that unregisters from atomic context out
from under its spinlock, patch 2 restores the grace period.

Bradley Morgan (2):
  clocksource/drivers/timer-ti-dm: Unregister CPU PM notifier outside of
    the timer lock
  PM: cpu: Restore synchronize_rcu() to cpu_pm_unregister_notifier()

 drivers/clocksource/timer-ti-dm.c | 9 ++++++---
 kernel/cpu_pm.c                   | 9 ++++++++-
 2 files changed, 14 insertions(+), 4 deletions(-)

-- 
2.47.3


             reply	other threads:[~2026-08-13  7:43 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-13  7:43 Bradley Morgan [this message]
2026-08-13  7:43 ` [PATCH 1/2] clocksource/drivers/timer-ti-dm: Unregister CPU PM notifier outside of the timer lock Bradley Morgan
2026-08-13  7:43 ` [PATCH 2/2] PM: cpu: Restore synchronize_rcu() to cpu_pm_unregister_notifier() Bradley Morgan

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