Backmerge tag 'v6.9-rc5' into drm-next

Linux 6.9-rc5

I've had a persistent msm failure on clang, and the fix is in fixes
so just pull it back to fix that.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 9 insertions, 8 deletions

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index fb0fdec8719a..d88b13076b79 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -7,6 +7,7 @@
  * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
  * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
  */
+#include <linux/compiler.h>
 #include <linux/cpu.h>
 #include <linux/err.h>
 #include <linux/hrtimer.h>
@@ -84,7 +85,7 @@ int tick_is_oneshot_available(void)
  */
 static void tick_periodic(int cpu)
 {
-	if (tick_do_timer_cpu == cpu) {
+	if (READ_ONCE(tick_do_timer_cpu) == cpu) {
 		raw_spin_lock(&jiffies_lock);
 		write_seqcount_begin(&jiffies_seq);
 
@@ -215,8 +216,8 @@ static void tick_setup_device(struct tick_device *td,
 		 * If no cpu took the do_timer update, assign it to
 		 * this cpu:
 		 */
-		if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
-			tick_do_timer_cpu = cpu;
+		if (READ_ONCE(tick_do_timer_cpu) == TICK_DO_TIMER_BOOT) {
+			WRITE_ONCE(tick_do_timer_cpu, cpu);
 			tick_next_period = ktime_get();
 #ifdef CONFIG_NO_HZ_FULL
 			/*
@@ -232,7 +233,7 @@ static void tick_setup_device(struct tick_device *td,
 						!tick_nohz_full_cpu(cpu)) {
 			tick_take_do_timer_from_boot();
 			tick_do_timer_boot_cpu = -1;
-			WARN_ON(tick_do_timer_cpu != cpu);
+			WARN_ON(READ_ONCE(tick_do_timer_cpu) != cpu);
 #endif
 		}
 
@@ -406,10 +407,10 @@ void tick_assert_timekeeping_handover(void)
 int tick_cpu_dying(unsigned int dying_cpu)
 {
 	/*
-	 * If the current CPU is the timekeeper, it's the only one that
-	 * can safely hand over its duty. Also all online CPUs are in
-	 * stop machine, guaranteed not to be idle, therefore it's safe
-	 * to pick any online successor.
+	 * If the current CPU is the timekeeper, it's the only one that can
+	 * safely hand over its duty. Also all online CPUs are in stop
+	 * machine, guaranteed not to be idle, therefore there is no
+	 * concurrency and it's safe to pick any online successor.
 	 */
 	if (tick_do_timer_cpu == dying_cpu)
 		tick_do_timer_cpu = cpumask_first(cpu_online_mask);