diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 5a01c4f..0ec5b7a 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1,34 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
- * linux/kernel/posix-timers.c
- *
- *
  * 2002-10-15  Posix Clocks & timers
  *                           by George Anzinger george@mvista.com
- *
  *			     Copyright (C) 2002 2003 by MontaVista Software.
  *
  * 2004-06-01  Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
  *			     Copyright (C) 2004 Boris Hu
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
-
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
- * MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA
- */
-
-/* These are all the functions necessary to implement
- * POSIX clocks & timers
+ * These are all the functions necessary to implement POSIX clocks & timers
  */
 #include <linux/mm.h>
 #include <linux/interrupt.h>
@@ -200,7 +179,7 @@
 }
 
 static int posix_clock_realtime_adj(const clockid_t which_clock,
-				    struct timex *t)
+				    struct __kernel_timex *t)
 {
 	return do_adjtimex(t);
 }
@@ -305,7 +284,7 @@
  * To protect against the timer going away while the interrupt is queued,
  * we require that the it_requeue_pending flag be set.
  */
-void posixtimer_rearm(struct siginfo *info)
+void posixtimer_rearm(struct kernel_siginfo *info)
 {
 	struct k_itimer *timr;
 	unsigned long flags;
@@ -463,7 +442,7 @@
 
 static void k_itimer_rcu_free(struct rcu_head *head)
 {
-	struct k_itimer *tmr = container_of(head, struct k_itimer, it.rcu);
+	struct k_itimer *tmr = container_of(head, struct k_itimer, rcu);
 
 	kmem_cache_free(posix_timers_cache, tmr);
 }
@@ -480,7 +459,7 @@
 	}
 	put_pid(tmr->it_pid);
 	sigqueue_free(tmr->sigq);
-	call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
+	call_rcu(&tmr->rcu, k_itimer_rcu_free);
 }
 
 static int common_timer_create(struct k_itimer *new_timer)
@@ -751,14 +730,14 @@
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
 
-COMPAT_SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
-		       struct compat_itimerspec __user *, setting)
+SYSCALL_DEFINE2(timer_gettime32, timer_t, timer_id,
+		struct old_itimerspec32 __user *, setting)
 {
 	struct itimerspec64 cur_setting;
 
 	int ret = do_timer_gettime(timer_id, &cur_setting);
 	if (!ret) {
-		if (put_compat_itimerspec64(&cur_setting, setting))
+		if (put_old_itimerspec32(&cur_setting, setting))
 			ret = -EFAULT;
 	}
 	return ret;
@@ -826,6 +805,35 @@
 	return hrtimer_try_to_cancel(&timr->it.real.timer);
 }
 
+static void common_timer_wait_running(struct k_itimer *timer)
+{
+	hrtimer_cancel_wait_running(&timer->it.real.timer);
+}
+
+/*
+ * On PREEMPT_RT this prevent priority inversion against softirq kthread in
+ * case it gets preempted while executing a timer callback. See comments in
+ * hrtimer_cancel_wait_running. For PREEMPT_RT=n this just results in a
+ * cpu_relax().
+ */
+static struct k_itimer *timer_wait_running(struct k_itimer *timer,
+					   unsigned long *flags)
+{
+	const struct k_clock *kc = READ_ONCE(timer->kclock);
+	timer_t timer_id = READ_ONCE(timer->it_id);
+
+	/* Prevent kfree(timer) after dropping the lock */
+	rcu_read_lock();
+	unlock_timer(timer, *flags);
+
+	if (!WARN_ON_ONCE(!kc->timer_wait_running))
+		kc->timer_wait_running(timer);
+
+	rcu_read_unlock();
+	/* Relock the timer. It might be not longer hashed. */
+	return lock_timer(timer_id, flags);
+}
+
 /* Set a POSIX.1b interval timer. */
 int common_timer_set(struct k_itimer *timr, int flags,
 		     struct itimerspec64 *new_setting,
@@ -865,13 +873,13 @@
 	return 0;
 }
 
-static int do_timer_settime(timer_t timer_id, int flags,
+static int do_timer_settime(timer_t timer_id, int tmr_flags,
 			    struct itimerspec64 *new_spec64,
 			    struct itimerspec64 *old_spec64)
 {
 	const struct k_clock *kc;
 	struct k_itimer *timr;
-	unsigned long flag;
+	unsigned long flags;
 	int error = 0;
 
 	if (!timespec64_valid(&new_spec64->it_interval) ||
@@ -880,8 +888,9 @@
 
 	if (old_spec64)
 		memset(old_spec64, 0, sizeof(*old_spec64));
+
+	timr = lock_timer(timer_id, &flags);
 retry:
-	timr = lock_timer(timer_id, &flag);
 	if (!timr)
 		return -EINVAL;
 
@@ -889,13 +898,16 @@
 	if (WARN_ON_ONCE(!kc || !kc->timer_set))
 		error = -EINVAL;
 	else
-		error = kc->timer_set(timr, flags, new_spec64, old_spec64);
+		error = kc->timer_set(timr, tmr_flags, new_spec64, old_spec64);
 
-	unlock_timer(timr, flag);
 	if (error == TIMER_RETRY) {
-		old_spec64 = NULL;	// We already got the old time...
+		// We already got the old time...
+		old_spec64 = NULL;
+		/* Unlocks and relocks the timer if it still exists */
+		timr = timer_wait_running(timr, &flags);
 		goto retry;
 	}
+	unlock_timer(timr, flags);
 
 	return error;
 }
@@ -924,9 +936,9 @@
 }
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
-COMPAT_SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
-		       struct compat_itimerspec __user *, new,
-		       struct compat_itimerspec __user *, old)
+SYSCALL_DEFINE4(timer_settime32, timer_t, timer_id, int, flags,
+		struct old_itimerspec32 __user *, new,
+		struct old_itimerspec32 __user *, old)
 {
 	struct itimerspec64 new_spec, old_spec;
 	struct itimerspec64 *rtn = old ? &old_spec : NULL;
@@ -934,12 +946,12 @@
 
 	if (!new)
 		return -EINVAL;
-	if (get_compat_itimerspec64(&new_spec, new))
+	if (get_old_itimerspec32(&new_spec, new))
 		return -EFAULT;
 
 	error = do_timer_settime(timer_id, flags, &new_spec, rtn);
 	if (!error && old) {
-		if (put_compat_itimerspec64(&old_spec, old))
+		if (put_old_itimerspec32(&old_spec, old))
 			error = -EFAULT;
 	}
 	return error;
@@ -972,13 +984,15 @@
 	struct k_itimer *timer;
 	unsigned long flags;
 
-retry_delete:
 	timer = lock_timer(timer_id, &flags);
+
+retry_delete:
 	if (!timer)
 		return -EINVAL;
 
-	if (timer_delete_hook(timer) == TIMER_RETRY) {
-		unlock_timer(timer, flags);
+	if (unlikely(timer_delete_hook(timer) == TIMER_RETRY)) {
+		/* Unlocks and relocks the timer if it still exists */
+		timer = timer_wait_running(timer, &flags);
 		goto retry_delete;
 	}
 
@@ -1001,23 +1015,16 @@
  */
 static void itimer_delete(struct k_itimer *timer)
 {
-	unsigned long flags;
-
 retry_delete:
-	spin_lock_irqsave(&timer->it_lock, flags);
+	spin_lock_irq(&timer->it_lock);
 
 	if (timer_delete_hook(timer) == TIMER_RETRY) {
-		unlock_timer(timer, flags);
+		spin_unlock_irq(&timer->it_lock);
 		goto retry_delete;
 	}
 	list_del(&timer->list);
-	/*
-	 * This keeps any tasks waiting on the spin lock from thinking
-	 * they got something (see the lock code above).
-	 */
-	timer->it_signal = NULL;
 
-	unlock_timer(timer, flags);
+	spin_unlock_irq(&timer->it_lock);
 	release_posix_timer(timer, IT_ID_SET);
 }
 
@@ -1068,22 +1075,28 @@
 	return error;
 }
 
-SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
-		struct timex __user *, utx)
+int do_clock_adjtime(const clockid_t which_clock, struct __kernel_timex * ktx)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
-	struct timex ktx;
-	int err;
 
 	if (!kc)
 		return -EINVAL;
 	if (!kc->clock_adj)
 		return -EOPNOTSUPP;
 
+	return kc->clock_adj(which_clock, ktx);
+}
+
+SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
+		struct __kernel_timex __user *, utx)
+{
+	struct __kernel_timex ktx;
+	int err;
+
 	if (copy_from_user(&ktx, utx, sizeof(ktx)))
 		return -EFAULT;
 
-	err = kc->clock_adj(which_clock, &ktx);
+	err = do_clock_adjtime(which_clock, &ktx);
 
 	if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
 		return -EFAULT;
@@ -1111,8 +1124,8 @@
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
 
-COMPAT_SYSCALL_DEFINE2(clock_settime, clockid_t, which_clock,
-		       struct compat_timespec __user *, tp)
+SYSCALL_DEFINE2(clock_settime32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 ts;
@@ -1120,14 +1133,14 @@
 	if (!kc || !kc->clock_set)
 		return -EINVAL;
 
-	if (compat_get_timespec64(&ts, tp))
+	if (get_old_timespec32(&ts, tp))
 		return -EFAULT;
 
 	return kc->clock_set(which_clock, &ts);
 }
 
-COMPAT_SYSCALL_DEFINE2(clock_gettime, clockid_t, which_clock,
-		       struct compat_timespec __user *, tp)
+SYSCALL_DEFINE2(clock_gettime32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 ts;
@@ -1138,46 +1151,32 @@
 
 	err = kc->clock_get(which_clock, &ts);
 
-	if (!err && compat_put_timespec64(&ts, tp))
+	if (!err && put_old_timespec32(&ts, tp))
 		err = -EFAULT;
 
 	return err;
 }
 
-#endif
-
-#ifdef CONFIG_COMPAT
-
-COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
-		       struct compat_timex __user *, utp)
+SYSCALL_DEFINE2(clock_adjtime32, clockid_t, which_clock,
+		struct old_timex32 __user *, utp)
 {
-	const struct k_clock *kc = clockid_to_kclock(which_clock);
-	struct timex ktx;
+	struct __kernel_timex ktx;
 	int err;
 
-	if (!kc)
-		return -EINVAL;
-	if (!kc->clock_adj)
-		return -EOPNOTSUPP;
-
-	err = compat_get_timex(&ktx, utp);
+	err = get_old_timex32(&ktx, utp);
 	if (err)
 		return err;
 
-	err = kc->clock_adj(which_clock, &ktx);
+	err = do_clock_adjtime(which_clock, &ktx);
 
 	if (err >= 0)
-		err = compat_put_timex(utp, &ktx);
+		err = put_old_timex32(utp, &ktx);
 
 	return err;
 }
 
-#endif
-
-#ifdef CONFIG_COMPAT_32BIT_TIME
-
-COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock,
-		       struct compat_timespec __user *, tp)
+SYSCALL_DEFINE2(clock_getres_time32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 ts;
@@ -1187,7 +1186,7 @@
 		return -EINVAL;
 
 	err = kc->clock_getres(which_clock, &ts);
-	if (!err && tp && compat_put_timespec64(&ts, tp))
+	if (!err && tp && put_old_timespec32(&ts, tp))
 		return -EFAULT;
 
 	return err;
@@ -1233,9 +1232,9 @@
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
 
-COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,
-		       struct compat_timespec __user *, rqtp,
-		       struct compat_timespec __user *, rmtp)
+SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags,
+		struct old_timespec32 __user *, rqtp,
+		struct old_timespec32 __user *, rmtp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 t;
@@ -1245,7 +1244,7 @@
 	if (!kc->nsleep)
 		return -EOPNOTSUPP;
 
-	if (compat_get_timespec64(&t, rqtp))
+	if (get_old_timespec32(&t, rqtp))
 		return -EFAULT;
 
 	if (!timespec64_valid(&t))
@@ -1274,6 +1273,7 @@
 	.timer_forward		= common_hrtimer_forward,
 	.timer_remaining	= common_hrtimer_remaining,
 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
 	.timer_arm		= common_hrtimer_arm,
 };
 
@@ -1289,6 +1289,7 @@
 	.timer_forward		= common_hrtimer_forward,
 	.timer_remaining	= common_hrtimer_remaining,
 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
 	.timer_arm		= common_hrtimer_arm,
 };
 
@@ -1319,6 +1320,7 @@
 	.timer_forward		= common_hrtimer_forward,
 	.timer_remaining	= common_hrtimer_remaining,
 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
 	.timer_arm		= common_hrtimer_arm,
 };
 
@@ -1334,6 +1336,7 @@
 	.timer_forward		= common_hrtimer_forward,
 	.timer_remaining	= common_hrtimer_remaining,
 	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
 	.timer_arm		= common_hrtimer_arm,
 };