The "timers: Provide timer_shutdown[_sync]()" patch series implemented a
useful feature that addresses various bugs caused by attempts to rearm
shutdown timers.

https://lore.kernel.org/all/20221123201306.823305113@linutronix.de/

However, this patch series was not fully backported to versions prior to
6.2, requiring separate patches for older kernels if these bugs were
encountered.

The biggest problem with this is that even if these bugs were discovered
and patched in the upstream kernel, if the maintainer or author didn't
create a separate backport patch for versions prior to 6.2, the bugs would
remain untouched in older kernels.

Therefore, to reduce the hassle of having to write a separate patch, we
should backport the remaining unbackported commits from the
"timers: Provide timer_shutdown[_sync]()" patch series to versions prior
to 6.2.

---
 Documentation/RCU/Design/Requirements/Requirements.rst      |   2 +-
 Documentation/core-api/local_ops.rst                        |   2 +-
 Documentation/kernel-hacking/locking.rst                    |  17 +++++++-----
 Documentation/timers/hrtimers.rst                           |   2 +-
 Documentation/translations/it_IT/kernel-hacking/locking.rst |  14 +++++-----
 Documentation/translations/zh_CN/core-api/local_ops.rst     |   2 +-
 arch/arm/mach-spear/time.c                                  |   8 +++---
 drivers/bluetooth/hci_qca.c                                 |  10 +++++--
 drivers/char/tpm/tpm-dev-common.c                           |   4 +--
 drivers/clocksource/arm_arch_timer.c                        |  12 ++++-----
 drivers/clocksource/timer-sp804.c                           |   6 ++---
 drivers/staging/wlan-ng/hfa384x_usb.c                       |   4 +--
 drivers/staging/wlan-ng/prism2usb.c                         |   6 ++---
 include/linux/timer.h                                       |  17 ++++++++++--
 kernel/time/timer.c                                         | 315 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------------------------------
 net/sunrpc/xprt.c                                           |   2 +-
 16 files changed, 322 insertions(+), 101 deletions(-)

On Sat, Nov 29, 2025 at 01:05:25AM +0900, Jeongjun Park wrote:
> The "timers: Provide timer_shutdown[_sync]()" patch series implemented a
> useful feature that addresses various bugs caused by attempts to rearm
> shutdown timers.
> 
> https://lore.kernel.org/all/20221123201306.823305113@linutronix.de/
> 
> However, this patch series was not fully backported to versions prior to
> 6.2, requiring separate patches for older kernels if these bugs were
> encountered.
> 
> The biggest problem with this is that even if these bugs were discovered
> and patched in the upstream kernel, if the maintainer or author didn't
> create a separate backport patch for versions prior to 6.2, the bugs would
> remain untouched in older kernels.
> 
> Therefore, to reduce the hassle of having to write a separate patch, we
> should backport the remaining unbackported commits from the
> "timers: Provide timer_shutdown[_sync]()" patch series to versions prior
> to 6.2.

You forgot to include commit 20739af07383 ("timers: Fix NULL function
pointer race in timer_shutdown_sync()") in this series.  I've now taken
them all, let's see how it goes!

thanks,

greg k-h