From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9CABA3E8C54; Thu, 23 Apr 2026 12:35:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776947755; cv=none; b=iQj/7/vG9mq9C6b/9rz735djyNcmZIUVY9a/H9My7N0E1PnELcXar0kq1xTYPvRuN+aJQk50rMW7IXNx/+9KkEXVwQQllogKh1fFiACvmfu+3DU/1HFnl8S2VheE4mBlPgjmnDc5G7OM/8g9g2HsyxE3w5m49EfbyZO1jERRvpk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776947755; c=relaxed/simple; bh=6Bce1R+T0bTnJZo+y/K7wzFqBs2vnN1ICd2M0WJpW1o=; h=Subject:To:Cc:From:Date:In-Reply-To:Message-ID:MIME-Version: Content-Type; b=TYiuQik0AwnpN3zZiEE8WVHmnjpZiinQTyxyDSWLhLyO07bBgomIQoJZpZr/0i6W+RgIOE6Ir5p+YYXtsrnJsb7iwtPmlUnHIbMGmHc5hexZl1sqiKccR080qD2YXIW/B5IgojQdX359ODrTli3b2jNf4B0v956tgzP5yDPXZ2E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PLNUNaWJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PLNUNaWJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31276C2BCAF; Thu, 23 Apr 2026 12:35:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776947755; bh=6Bce1R+T0bTnJZo+y/K7wzFqBs2vnN1ICd2M0WJpW1o=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=PLNUNaWJ09e2GRdMDFuMKrHvBdkaZxj1VWXGoikIe0jocLELjoISLCU7U4X9Jf3sP PW1WmI3r3+sEv3CDhwMH/sYKGMxJdA+JvUvPahAS/yxfQugqkpv2cBncrLE7ozNbyH hsF5ekLSX80FGvE/hcLsc2H+JoGuZpo/RFL6HB5w= Subject: Patch "timers: Split [try_to_]del_timer[_sync]() to prepare for shutdown mode" has been added to the 5.10-stable tree To: Julia.Lawall@inria.fr,aha310510@gmail.com,akpm@linux-foundation.org,anna-maria@linutronix.de,arnd@arndb.de,gregkh@linuxfoundation.org,jacob.e.keller@intel.com,linux-staging@lists.linux.dev,linux@roeck-us.net,luiz.dentz@gmail.com,marcel@holtmann.org,maz@kernel.org,peterz@infradead.org,rostedt@goodmis.org,sboyd@kernel.org,tglx@linutronix.de,viresh.kumar@linaro.org,zouyipeng@huawei.com Cc: From: Date: Thu, 23 Apr 2026 14:35:08 +0200 In-Reply-To: <20260219171310.118170-11-aha310510@gmail.com> Message-ID: <2026042308-stencil-relay-aaff@gregkh> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore This is a note to let you know that I've just added the patch titled timers: Split [try_to_]del_timer[_sync]() to prepare for shutdown mode to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: timers-split-del_timer-to-prepare-for-shutdown-mode.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From aha310510@gmail.com Thu Feb 19 18:13:58 2026 From: Jeongjun Park Date: Fri, 20 Feb 2026 02:13:05 +0900 Subject: timers: Split [try_to_]del_timer[_sync]() to prepare for shutdown mode To: stable@vger.kernel.org Cc: gregkh@linuxfoundation.org, tglx@linutronix.de, Julia.Lawall@inria.fr, akpm@linux-foundation.org, anna-maria@linutronix.de, arnd@arndb.de, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, linux@roeck-us.net, luiz.dentz@gmail.com, marcel@holtmann.org, maz@kernel.org, peterz@infradead.org, rostedt@goodmis.org, sboyd@kernel.org, viresh.kumar@linaro.org, zouyipeng@huawei.com, aha310510@gmail.com, linux-staging@lists.linux.dev, Jacob Keller Message-ID: <20260219171310.118170-11-aha310510@gmail.com> From: Thomas Gleixner [ Upstream commit 8553b5f2774a66b1f293b7d783934210afb8f23c ] Tearing down timers which have circular dependencies to other functionality, e.g. workqueues, where the timer can schedule work and work can arm timers, is not trivial. In those cases it is desired to shutdown the timer in a way which prevents rearming of the timer. The mechanism to do so is to set timer->function to NULL and use this as an indicator for the timer arming functions to ignore the (re)arm request. Split the inner workings of try_do_del_timer_sync(), del_timer_sync() and del_timer() into helper functions to prepare for implementing the shutdown functionality. No functional change. Co-developed-by: Steven Rostedt Signed-off-by: Steven Rostedt Signed-off-by: Thomas Gleixner Tested-by: Guenter Roeck Reviewed-by: Jacob Keller Reviewed-by: Anna-Maria Behnsen Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home Link: https://lore.kernel.org/all/20221110064101.429013735@goodmis.org Link: https://lore.kernel.org/r/20221123201625.195147423@linutronix.de Signed-off-by: Jeongjun Park Signed-off-by: Greg Kroah-Hartman --- kernel/time/timer.c | 135 +++++++++++++++++++++++++++++++++------------------- 1 file changed, 88 insertions(+), 47 deletions(-) --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1245,20 +1245,14 @@ out_unlock: EXPORT_SYMBOL_GPL(add_timer_on); /** - * timer_delete - Deactivate a timer + * __timer_delete - Internal function: Deactivate a timer * @timer: The timer to be deactivated * - * The function only deactivates a pending timer, but contrary to - * timer_delete_sync() it does not take into account whether the timer's - * callback function is concurrently executed on a different CPU or not. - * It neither prevents rearming of the timer. If @timer can be rearmed - * concurrently then the return value of this function is meaningless. - * * Return: * * %0 - The timer was not pending * * %1 - The timer was pending and deactivated */ -int timer_delete(struct timer_list *timer) +static int __timer_delete(struct timer_list *timer) { struct timer_base *base; unsigned long flags; @@ -1274,25 +1268,37 @@ int timer_delete(struct timer_list *time return ret; } -EXPORT_SYMBOL(timer_delete); /** - * try_to_del_timer_sync - Try to deactivate a timer - * @timer: Timer to deactivate + * timer_delete - Deactivate a timer + * @timer: The timer to be deactivated * - * This function tries to deactivate a timer. On success the timer is not - * queued and the timer callback function is not running on any CPU. + * The function only deactivates a pending timer, but contrary to + * timer_delete_sync() it does not take into account whether the timer's + * callback function is concurrently executed on a different CPU or not. + * It neither prevents rearming of the timer. If @timer can be rearmed + * concurrently then the return value of this function is meaningless. * - * This function does not guarantee that the timer cannot be rearmed right - * after dropping the base lock. That needs to be prevented by the calling - * code if necessary. + * Return: + * * %0 - The timer was not pending + * * %1 - The timer was pending and deactivated + */ +int timer_delete(struct timer_list *timer) +{ + return __timer_delete(timer); +} +EXPORT_SYMBOL(timer_delete); + +/** + * __try_to_del_timer_sync - Internal function: Try to deactivate a timer + * @timer: Timer to deactivate * * Return: * * %0 - The timer was not pending * * %1 - The timer was pending and deactivated * * %-1 - The timer callback function is running on a different CPU */ -int try_to_del_timer_sync(struct timer_list *timer) +static int __try_to_del_timer_sync(struct timer_list *timer) { struct timer_base *base; unsigned long flags; @@ -1309,6 +1315,27 @@ int try_to_del_timer_sync(struct timer_l return ret; } + +/** + * try_to_del_timer_sync - Try to deactivate a timer + * @timer: Timer to deactivate + * + * This function tries to deactivate a timer. On success the timer is not + * queued and the timer callback function is not running on any CPU. + * + * This function does not guarantee that the timer cannot be rearmed right + * after dropping the base lock. That needs to be prevented by the calling + * code if necessary. + * + * Return: + * * %0 - The timer was not pending + * * %1 - The timer was pending and deactivated + * * %-1 - The timer callback function is running on a different CPU + */ +int try_to_del_timer_sync(struct timer_list *timer) +{ + return __try_to_del_timer_sync(timer); +} EXPORT_SYMBOL(try_to_del_timer_sync); #ifdef CONFIG_PREEMPT_RT @@ -1385,6 +1412,49 @@ static inline void del_timer_wait_runnin #endif /** + * __timer_delete_sync - Internal function: Deactivate a timer and wait + * for the handler to finish. + * @timer: The timer to be deactivated + * + * Return: + * * %0 - The timer was not pending + * * %1 - The timer was pending and deactivated + */ +static int __timer_delete_sync(struct timer_list *timer) +{ + int ret; + +#ifdef CONFIG_LOCKDEP + unsigned long flags; + + /* + * If lockdep gives a backtrace here, please reference + * the synchronization rules above. + */ + local_irq_save(flags); + lock_map_acquire(&timer->lockdep_map); + lock_map_release(&timer->lockdep_map); + local_irq_restore(flags); +#endif + /* + * don't use it in hardirq context, because it + * could lead to deadlock. + */ + WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE)); + + do { + ret = __try_to_del_timer_sync(timer); + + if (unlikely(ret < 0)) { + del_timer_wait_running(timer); + cpu_relax(); + } + } while (ret < 0); + + return ret; +} + +/** * timer_delete_sync - Deactivate a timer and wait for the handler to finish. * @timer: The timer to be deactivated * @@ -1425,36 +1495,7 @@ static inline void del_timer_wait_runnin */ int timer_delete_sync(struct timer_list *timer) { - int ret; - -#ifdef CONFIG_LOCKDEP - unsigned long flags; - - /* - * If lockdep gives a backtrace here, please reference - * the synchronization rules above. - */ - local_irq_save(flags); - lock_map_acquire(&timer->lockdep_map); - lock_map_release(&timer->lockdep_map); - local_irq_restore(flags); -#endif - /* - * don't use it in hardirq context, because it - * could lead to deadlock. - */ - WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE)); - - do { - ret = try_to_del_timer_sync(timer); - - if (unlikely(ret < 0)) { - del_timer_wait_running(timer); - cpu_relax(); - } - } while (ret < 0); - - return ret; + return __timer_delete_sync(timer); } EXPORT_SYMBOL(timer_delete_sync); Patches currently in stable-queue which might be from aha310510@gmail.com are queue-5.10/timers-update-the-documentation-to-reflect-on-the-new-timer_shutdown-api.patch queue-5.10/clocksource-drivers-arm_arch_timer-do-not-use-timer-namespace-for-timer_shutdown-function.patch queue-5.10/timers-split-del_timer-to-prepare-for-shutdown-mode.patch queue-5.10/arm-spear-do-not-use-timer-namespace-for-timer_shutdown-function.patch queue-5.10/media-as102-fix-to-not-free-memory-after-the-device-is-registered-in-as102_usb_probe.patch queue-5.10/timers-add-shutdown-mechanism-to-the-internal-functions.patch queue-5.10/timers-provide-timer_shutdown.patch queue-5.10/timers-rename-del_timer-to-timer_delete.patch queue-5.10/timers-replace-bug_on-s.patch queue-5.10/bluetooth-hci_qca-fix-the-teardown-problem-for-real.patch queue-5.10/timers-fix-null-function-pointer-race-in-timer_shutdown_sync.patch queue-5.10/documentation-replace-del_timer-del_timer_sync.patch queue-5.10/documentation-remove-bogus-claim-about-del_timer_sync.patch queue-5.10/timers-silently-ignore-timers-with-a-null-function.patch queue-5.10/timers-get-rid-of-del_singleshot_timer_sync.patch queue-5.10/media-hackrf-fix-to-not-free-memory-after-the-device-is-registered-in-hackrf_probe.patch queue-5.10/clocksource-drivers-sp804-do-not-use-timer-namespace-for-timer_shutdown-function.patch