Patch "Documentation: Remove bogus claim about del_timer_sync()" has been added to the 5.10-stable tree

gregkh
2026-04-23T12:35:21Z

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

Documentation: Remove bogus claim about del_timer_sync()

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:
documentation-remove-bogus-claim-about-del_timer_sync.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 linux-staging+bounces-37306-greg=kroah.com@lists.linux.dev Thu Feb 19 18:13:29 2026
From: Jeongjun Park <aha310510@gmail.com>
Date: Fri, 20 Feb 2026 02:12:56 +0900
Subject: Documentation: Remove bogus claim about del_timer_sync()
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: <20260219171310.118170-2-aha310510@gmail.com>

From: Thomas Gleixner <tglx@linutronix.de>

[ Upstream commit b0b0aa5d858d4d2fe39a5e4486e0550e858108f6 ]

del_timer_sync() does not return the number of times it tried to delete the
timer which rearms itself. It's clearly documented:

The function returns whether it has deactivated a pending timer or not.

This part of the documentation is from 2003 where del_timer_sync() really
returned the number of deletion attempts for unknown reasons. The code
was rewritten in 2005, but the documentation was not updated.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Link: https://lore.kernel.org/r/20221123201624.452282769@linutronix.de
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/kernel-hacking/locking.rst | 3 +--
Documentation/translations/it_IT/kernel-hacking/locking.rst | 4 +---
2 files changed, 2 insertions(+), 5 deletions(-)

--- a/Documentation/kernel-hacking/locking.rst
+++ b/Documentation/kernel-hacking/locking.rst
@@ -1015,8 +1015,7 @@ Another common problem is deleting timer
calling add_timer() at the end of their timer function).
Because this is a fairly common case which is prone to races, you should
use del_timer_sync() (``include/linux/timer.h``) to
-handle this case. It returns the number of times the timer had to be
-deleted before we finally stopped it from adding itself back in.
+handle this case.

Locking Speed
=============
--- a/Documentation/translations/it_IT/kernel-hacking/locking.rst
+++ b/Documentation/translations/it_IT/kernel-hacking/locking.rst
@@ -1037,9 +1037,7 @@ Un altro problema è l'eliminazione dei
da soli (chiamando add_timer() alla fine della loro esecuzione).
Dato che questo è un problema abbastanza comune con una propensione
alle corse critiche, dovreste usare del_timer_sync()
-(``include/linux/timer.h``) per gestire questo caso. Questa ritorna il
-numero di volte che il temporizzatore è stato interrotto prima che
-fosse in grado di fermarlo senza che si riavviasse.
+(``include/linux/timer.h``) per gestire questo caso.

Velocità della sincronizzazione
===============================

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