Patch "timers: Update the documentation to reflect on the new timer_shutdown() API" has been added to the 5.10-stable tree

gregkh
2026-04-23T12:35:58Z

This is a note to let you know that I've just added the patch titled

timers: Update the documentation to reflect on the new timer_shutdown() API

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-update-the-documentation-to-reflect-on-the-new-timer_shutdown-api.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 <stable@vger.kernel.org> know about it.

From aha310510@gmail.com Thu Feb 19 18:14:11 2026
From: Jeongjun Park <aha310510@gmail.com>
Date: Fri, 20 Feb 2026 02:13:08 +0900
Subject: timers: Update the documentation to reflect on the new timer_shutdown() API
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 <jacob.e.keller@intel.com>
Message-ID: <20260219171310.118170-14-aha310510@gmail.com>

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

[ Upstream commit a31323bef2b66455920d054b160c17d4240f8fd4 ]

In order to make sure that a timer is not re-armed after it is stopped
before freeing, a new shutdown state is added to the timer code. The API
timer_shutdown_sync() and timer_shutdown() must be called before the
object that holds the timer can be freed.

Update the documentation to reflect this new workflow.

[ tglx: Updated to the new semantics and updated the zh_CN version ]

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Link: https://lore.kernel.org/r/20221110064147.712934793@goodmis.org
Link: https://lore.kernel.org/r/20221123201625.375284489@linutronix.de
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/RCU/Design/Requirements/Requirements.rst | 2 +-
Documentation/core-api/local_ops.rst | 2 +-
Documentation/kernel-hacking/locking.rst | 5 +++++
3 files changed, 7 insertions(+), 2 deletions(-)

--- a/Documentation/RCU/Design/Requirements/Requirements.rst
+++ b/Documentation/RCU/Design/Requirements/Requirements.rst
@@ -1858,7 +1858,7 @@ unloaded. After a given module has been
one of its functions results in a segmentation fault. The module-unload
functions must therefore cancel any delayed calls to loadable-module
functions, for example, any outstanding ``mod_timer()`` must be dealt
-with via ``timer_delete_sync()`` or similar.
+with via ``timer_shutdown_sync()`` or similar.

Unfortunately, there is no way to cancel an RCU callback; once you
invoke ``call_rcu()``, the callback function is eventually going to be
--- a/Documentation/core-api/local_ops.rst
+++ b/Documentation/core-api/local_ops.rst
@@ -191,7 +191,7 @@ Here is a sample module which implements

static void __exit test_exit(void)
{
- timer_delete_sync(&test_timer);
+ timer_shutdown_sync(&test_timer);
}

module_init(test_init);
--- a/Documentation/kernel-hacking/locking.rst
+++ b/Documentation/kernel-hacking/locking.rst
@@ -1016,6 +1016,11 @@ calling add_timer() at the end of their
Because this is a fairly common case which is prone to races, you should
use timer_delete_sync() (``include/linux/timer.h``) to handle this case.

+Before freeing a timer, timer_shutdown() or timer_shutdown_sync() should be
+called which will keep it from being rearmed. Any subsequent attempt to
+rearm the timer will be silently ignored by the core code.
+
+
Locking Speed
=============

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