5.4-stable patches

added patches:
	tick-common-align-tick-period-during-sched_timer-setup.patch

diff --git a/queue-5.4/series b/queue-5.4/series
index 8a3d0a78e2c3bfc4910dea91e0e927dda9ecf7ab..5be7fd2160ccf61b7d4dd5f6b3a51f22b2567204 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -4,3 +4,4 @@ list-add-list_del_init_careful-to-go-with-list_empty.patch
 epoll-ep_autoremove_wake_function-should-use-list_de.patch
 tracing-add-tracing_reset_all_online_cpus_unlocked-function.patch
 x86-purgatory-remove-pgo-flags.patch
+tick-common-align-tick-period-during-sched_timer-setup.patch

diff --git a/queue-5.4/tick-common-align-tick-period-during-sched_timer-setup.patch b/queue-5.4/tick-common-align-tick-period-during-sched_timer-setup.patch
new file mode 100644 (file)
index 0000000..6480d97
--- /dev/null
+++ b/queue-5.4/tick-common-align-tick-period-during-sched_timer-setup.patch
@@ -0,0 +1,95 @@
+From 13bb06f8dd42071cb9a49f6e21099eea05d4b856 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 15 Jun 2023 11:18:30 +0200
+Subject: tick/common: Align tick period during sched_timer setup
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit 13bb06f8dd42071cb9a49f6e21099eea05d4b856 upstream.
+
+The tick period is aligned very early while the first clock_event_device is
+registered. At that point the system runs in periodic mode and switches
+later to one-shot mode if possible.
+
+The next wake-up event is programmed based on the aligned value
+(tick_next_period) but the delta value, that is used to program the
+clock_event_device, is computed based on ktime_get().
+
+With the subtracted offset, the device fires earlier than the exact time
+frame. With a large enough offset the system programs the timer for the
+next wake-up and the remaining time left is too small to make any boot
+progress. The system hangs.
+
+Move the alignment later to the setup of tick_sched timer. At this point
+the system switches to oneshot mode and a high resolution clocksource is
+available. At this point it is safe to align tick_next_period because
+ktime_get() will now return accurate (not jiffies based) time.
+
+[bigeasy: Patch description + testing].
+
+Fixes: e9523a0d81899 ("tick/common: Align tick period with the HZ tick.")
+Reported-by: Mathias Krause <minipli@grsecurity.net>
+Reported-by: "Bhatnagar, Rishabh" <risbhat@amazon.com>
+Suggested-by: Mathias Krause <minipli@grsecurity.net>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Richard W.M. Jones <rjones@redhat.com>
+Tested-by: Mathias Krause <minipli@grsecurity.net>
+Acked-by: SeongJae Park <sj@kernel.org>
+Cc: stable@vger.kernel.org
+Link: https://lore.kernel.org/5a56290d-806e-b9a5-f37c-f21958b5a8c0@grsecurity.net
+Link: https://lore.kernel.org/12c6f9a3-d087-b824-0d05-0d18c9bc1bf3@amazon.com
+Link: https://lore.kernel.org/r/20230615091830.RxMV2xf_@linutronix.de
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ kernel/time/tick-common.c |   13 +------------
+ kernel/time/tick-sched.c  |   13 ++++++++++++-
+ 2 files changed, 13 insertions(+), 13 deletions(-)
+
+--- a/kernel/time/tick-common.c
++++ b/kernel/time/tick-common.c
+@@ -216,19 +216,8 @@ static void tick_setup_device(struct tic
+                * this cpu:
+                */
+               if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
+-                      ktime_t next_p;
+-                      u32 rem;
+-
+                       tick_do_timer_cpu = cpu;
+-
+-                      next_p = ktime_get();
+-                      div_u64_rem(next_p, TICK_NSEC, &rem);
+-                      if (rem) {
+-                              next_p -= rem;
+-                              next_p += TICK_NSEC;
+-                      }
+-
+-                      tick_next_period = next_p;
++                      tick_next_period = ktime_get();
+ #ifdef CONFIG_NO_HZ_FULL
+                       /*
+                        * The boot CPU may be nohz_full, in which case set
+--- a/kernel/time/tick-sched.c
++++ b/kernel/time/tick-sched.c
+@@ -129,8 +129,19 @@ static ktime_t tick_init_jiffy_update(vo
+       raw_spin_lock(&jiffies_lock);
+       write_seqcount_begin(&jiffies_seq);
+       /* Did we start the jiffies update yet ? */
+-      if (last_jiffies_update == 0)
++      if (last_jiffies_update == 0) {
++              u32 rem;
++
++              /*
++               * Ensure that the tick is aligned to a multiple of
++               * TICK_NSEC.
++               */
++              div_u64_rem(tick_next_period, TICK_NSEC, &rem);
++              if (rem)
++                      tick_next_period += TICK_NSEC - rem;
++
+               last_jiffies_update = tick_next_period;
++      }
+       period = last_jiffies_update;
+       write_seqcount_end(&jiffies_seq);
+       raw_spin_unlock(&jiffies_lock);