tick_freeze() acquires a raw spinlock (tick_freeze_lock). Later in the
callchain (timekeeping_suspend() -> mc146818_avoid_UIP()) the RTC driver
acquires a spinlock which becomes a sleeping lock on PREEMPT_RT.  Lockdep
complains about this lock nesting.

Add a lockdep override for this special case and a comment explaining
why it is okay.

Reported-by: Borislav Petkov <bp@alien8.de>
Reported-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250404133429.pnAzf-eF@linutronix.de
Closes: https://lore.kernel.org/all/20250330113202.GAZ-krsjAnurOlTcp-@fat_crate.local/
Closes: https://lore.kernel.org/all/CAP-bSRZ0CWyZZsMtx046YV8L28LhY0fson2g4EqcwRAVN1Jk+Q@mail.gmail.com/

The "function" field of struct hrtimer has been changed to private, but
two instances have not been converted to use ACCESS_PRIVATE().

Convert them to use ACCESS_PRIVATE().

Fixes: 04257da0c99c ("hrtimers: Make callback function pointer private")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250408103854.1851093-1-namcao@linutronix.de
Closes: https://lore.kernel.org/oe-kbuild-all/202504071931.vOVl13tt-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202504072155.5UAZjYGU-lkp@intel.com/

Pull timer cleanups from Thomas Gleixner:
 "A set of final cleanups for the timer subsystem:

   - Convert all del_timer[_sync]() instances over to the new
     timer_delete[_sync]() API and remove the legacy wrappers.

     Conversion was done with coccinelle plus some manual fixups as
     coccinelle chokes on scoped_guard().

   - The final cleanup of the hrtimer_init() to hrtimer_setup()
     conversion.

     This has been delayed to the end of the merge window, so that all
     patches which have been merged through other trees are in mainline
     and all new users are catched.

  Doing this right before rc1 ensures that new code which is merged post
  rc1 is not introducing new instances of the original functionality"

* tag 'timers-cleanups-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tracing/timers: Rename the hrtimer_init event to hrtimer_setup
  hrtimers: Rename debug_init_on_stack() to debug_setup_on_stack()
  hrtimers: Rename debug_init() to debug_setup()
  hrtimers: Rename __hrtimer_init_sleeper() to __hrtimer_setup_sleeper()
  hrtimers: Remove unnecessary NULL check in hrtimer_start_range_ns()
  hrtimers: Make callback function pointer private
  hrtimers: Merge __hrtimer_init() into __hrtimer_setup()
  hrtimers: Switch to use __htimer_setup()
  hrtimers: Delete hrtimer_init()
  treewide: Convert new and leftover hrtimer_init() users
  treewide: Switch/rename to timer_delete[_sync]()

The function hrtimer_init() doesn't exist anymore. It was replaced by
hrtimer_setup().

Thus, rename the hrtimer_init trace event to hrtimer_setup to keep it
consistent.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/cba84c3d853c5258aa3a262363a6eac08e2c7afc.1738746927.git.namcao@linutronix.de

All the hrtimer_init*() functions have been renamed to hrtimer_setup*().
Rename debug_init_on_stack() to debug_setup_on_stack() as well, to keep the
names consistent.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/073cf6162779a2f5b12624677d4c49ee7eccc1ed.1738746927.git.namcao@linutronix.de

All the hrtimer_init*() functions have been renamed to hrtimer_setup*().
Rename debug_init() to debug_setup() as well, to keep the names consistent.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/4b730c1f79648b16a1c5413f928fdc2e138dfc43.1738746927.git.namcao@linutronix.de

All the hrtimer_init*() functions have been renamed to hrtimer_setup*().
Rename __hrtimer_init_sleeper() to __hrtimer_setup_sleeper() as well, to
keep the names consistent.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/807694aedad9353421c4a7347629a30c5c31026f.1738746927.git.namcao@linutronix.de

The struct hrtimer::function field can only be changed using
hrtimer_setup*() or hrtimer_update_function(), and both already null-check
'function'. Therefore, null-checking 'function' in hrtimer_start_range_ns()
is not necessary.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/4661c571ee87980c340ccc318fc1a473c0c8f6bc.1738746927.git.namcao@linutronix.de

Make the struct hrtimer::function field private, to prevent users from
changing this field in an unsafe way. hrtimer_update_function() should be
used if the callback function needs to be changed.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/7d0e6e0c5c59a64a9bea940051aac05d750bc0c2.1738746927.git.namcao@linutronix.de

__hrtimer_init() is only called by __hrtimer_setup(). Simplify by merging
__hrtimer_init() into __hrtimer_setup().

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/8a0a847a35f711f66b2d05b57255aa44e7e61279.1738746927.git.namcao@linutronix.de