Patch "timers: Update the documentation to reflect on the new timer_shutdown() API" has been added to the 5.15-stable tree

[<gregkh@linuxfoundation.org>]

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 5.15-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-5.15 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 Fri Nov 28 17:06:59 2025
From: Jeongjun Park <aha310510@gmail.com>
Date: Sat, 29 Nov 2025 01:05:38 +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, aha310510@gmail.com, linux-staging@lists.linux.dev, Jacob Keller <jacob.e.keller@intel.com>
Message-ID: <20251128160539.358938-14-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 +++++
 Documentation/translations/zh_CN/core-api/local_ops.rst |    2 +-
 4 files changed, 8 insertions(+), 3 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
@@ -1010,6 +1010,11 @@ 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
 
+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
 =============
 
--- a/Documentation/translations/zh_CN/core-api/local_ops.rst
+++ b/Documentation/translations/zh_CN/core-api/local_ops.rst
@@ -185,7 +185,7 @@ UP之间没有不同的行为，在你çš
 
     static void __exit test_exit(void)
     {
-            timer_delete_sync(&test_timer);
+            timer_shutdown_sync(&test_timer);
     }
 
     module_init(test_init);


Patches currently in stable-queue which might be from aha310510@gmail.com are

queue-5.15/timers-update-the-documentation-to-reflect-on-the-new-timer_shutdown-api.patch
queue-5.15/clocksource-drivers-arm_arch_timer-do-not-use-timer-namespace-for-timer_shutdown-function.patch
queue-5.15/timers-split-del_timer-to-prepare-for-shutdown-mode.patch
queue-5.15/arm-spear-do-not-use-timer-namespace-for-timer_shutdown-function.patch
queue-5.15/timers-add-shutdown-mechanism-to-the-internal-functions.patch
queue-5.15/timers-provide-timer_shutdown.patch
queue-5.15/timers-rename-del_timer-to-timer_delete.patch
queue-5.15/timers-replace-bug_on-s.patch
queue-5.15/bluetooth-hci_qca-fix-the-teardown-problem-for-real.patch
queue-5.15/documentation-replace-del_timer-del_timer_sync.patch
queue-5.15/documentation-remove-bogus-claim-about-del_timer_sync.patch
queue-5.15/timers-silently-ignore-timers-with-a-null-function.patch
queue-5.15/timers-get-rid-of-del_singleshot_timer_sync.patch
queue-5.15/clocksource-drivers-sp804-do-not-use-timer-namespace-for-timer_shutdown-function.patch