linux-stable.git/kernel/time, branch linux-5.11.y

posix-timers: Preserve return value in clock_adjtime32()

2021-05-12T06:37:12+00:00

commit 2d036dfa5f10df9782f5278fc591d79d283c1fad upstream.

The return value on success (>= 0) is overwritten by the return value of
put_old_timex32(). That works correct in the fault case, but is wrong for
the success case where put_old_timex32() returns 0.

Just check the return value of put_old_timex32() and return -EFAULT in case
it is not zero.

[ tglx: Massage changelog ]

Fixes: 3a4d44b61625 ("ntp: Move adjtimex related compat syscalls to native counterparts")
Signed-off-by: Chen Jun 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Richard Cochran 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210414030449.90692-1-chenjun102@huawei.com
Signed-off-by: Greg Kroah-Hartman

kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data()

2021-03-24T10:54:15+00:00

commit 5abbe51a526253b9f003e9a0a195638dc882d660 upstream.

Preparation for fixing get_nr_restart_syscall() on X86 for COMPAT.

Add a new helper which sets restart_block->fn and calls a dummy
arch_set_restart_data() helper.

Fixes: 609c19a385c8 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code")
Signed-off-by: Oleg Nesterov 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210201174641.GA17871@redhat.com
Signed-off-by: Greg Kroah-Hartman

hrtimer: Update softirq_expires_next correctly after __hrtimer_get_next_event()

2021-03-17T16:11:43+00:00

[ Upstream commit 46eb1701c046cc18c032fa68f3c8ccbf24483ee4 ]

hrtimer_force_reprogram() and hrtimer_interrupt() invokes
__hrtimer_get_next_event() to find the earliest expiry time of hrtimer
bases. __hrtimer_get_next_event() does not update
cpu_base::[softirq_]_expires_next to preserve reprogramming logic. That
needs to be done at the callsites.

hrtimer_force_reprogram() updates cpu_base::softirq_expires_next only when
the first expiring timer is a softirq timer and the soft interrupt is not
activated. That's wrong because cpu_base::softirq_expires_next is left
stale when the first expiring timer of all bases is a timer which expires
in hard interrupt context. hrtimer_interrupt() does never update
cpu_base::softirq_expires_next which is wrong too.

That becomes a problem when clock_settime() sets CLOCK_REALTIME forward and
the first soft expiring timer is in the CLOCK_REALTIME_SOFT base. Setting
CLOCK_REALTIME forward moves the clock MONOTONIC based expiry time of that
timer before the stale cpu_base::softirq_expires_next.

cpu_base::softirq_expires_next is cached to make the check for raising the
soft interrupt fast. In the above case the soft interrupt won't be raised
until clock monotonic reaches the stale cpu_base::softirq_expires_next
value. That's incorrect, but what's worse it that if the softirq timer
becomes the first expiring timer of all clock bases after the hard expiry
timer has been handled the reprogramming of the clockevent from
hrtimer_interrupt() will result in an interrupt storm. That happens because
the reprogramming does not use cpu_base::softirq_expires_next, it uses
__hrtimer_get_next_event() which returns the actual expiry time. Once clock
MONOTONIC reaches cpu_base::softirq_expires_next the soft interrupt is
raised and the storm subsides.

Change the logic in hrtimer_force_reprogram() to evaluate the soft and hard
bases seperately, update softirq_expires_next and handle the case when a
soft expiring timer is the first of all bases by comparing the expiry times
and updating the required cpu base fields. Split this functionality into a
separate function to be able to use it in hrtimer_interrupt() as well
without copy paste.

Fixes: 5da70160462e ("hrtimer: Implement support for softirq based hrtimers")
Reported-by: Mikael Beckius 
Suggested-by: Thomas Gleixner 
Tested-by: Mikael Beckius 
Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20210223160240.27518-1-anna-maria@linutronix.de
Signed-off-by: Sasha Levin

ntp: Use freezable workqueue for RTC synchronization

2021-02-05T17:03:13+00:00

The bug fixed by commit e3fab2f3de081e98 ("ntp: Fix RTC synchronization on
32-bit platforms") revealed an underlying issue: RTC synchronization may
happen anytime, even while the system is partially suspended.

On systems where the RTC is connected to an I2C bus, the I2C bus controller
may already or still be suspended, triggering a WARNING during suspend or
resume from s2ram:

    WARNING: CPU: 0 PID: 124 at drivers/i2c/i2c-core.h:54 __i2c_transfer+0x634/0x680
    i2c i2c-6: Transfer while suspended
    [...]
    Workqueue: events_power_efficient sync_hw_clock
    [...]
      (__i2c_transfer)
      (i2c_transfer)
      (regmap_i2c_read)
      ...
      (da9063_rtc_set_time)
      (rtc_set_time)
      (sync_hw_clock)
      (process_one_work)

Fix this race condition by using the freezable instead of the normal
power-efficient workqueue.

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Thomas Gleixner 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20210125143039.1051912-1-geert+renesas@glider.be

ntp: Fix RTC synchronization on 32-bit platforms

2021-01-12T20:13:01+00:00

Due to an integer overflow, RTC synchronization now happens every 2s
instead of the intended 11 minutes.  Fix this by forcing 64-bit
arithmetic for the sync period calculation.

Annotate the other place which multiplies seconds for consistency as well.

Fixes: c9e6189fb03123a7 ("ntp: Make the RTC synchronization more reliable")
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20210111103956.290378-1-geert+renesas@glider.be

timekeeping: Remove unused get_seconds()

2021-01-12T20:13:01+00:00

The get_seconds() cleanup seems to have been completed, now it is
time to delete the legacy interface to avoid misuse later.

Signed-off-by: Chunguang Xu 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/1606816351-26900-1-git-send-email-brookxu@tencent.com

Merge tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-12-27T17:03:41+00:00

Pull timer fixes from Ingo Molnar:
 "Update/fix two CPU sanity checks in the hotplug and the boot code, and
  fix a typo in the Kconfig help text.

  [ Context: the first two commits are the result of an ongoing
    annotation+review work of (intentional) tick_do_timer_cpu() data
    races reported by KCSAN, but the annotations aren't fully cooked
    yet ]"

* tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Fix spelling mistake in Kconfig "fullfill" -> "fulfill"
  tick/sched: Remove bogus boot "safety" check
  tick: Remove pointless cpu valid check in hotplug code

timekeeping: Fix spelling mistake in Kconfig "fullfill" -> "fulfill"

2020-12-18T22:15:00+00:00

There is a spelling mistake in the Kconfig help text. Fix it.

Signed-off-by: Colin Ian King 
Signed-off-by: Thomas Gleixner 
Acked-by: Linus Walleij 
Link: https://lore.kernel.org/r/20201217171705.57586-1-colin.king@canonical.com

tick/sched: Remove bogus boot "safety" check

2020-12-16T10:26:27+00:00

can_stop_idle_tick() checks whether the do_timer() duty has been taken over
by a CPU on boot. That's silly because the boot CPU always takes over with
the initial clockevent device.

But even if no CPU would have installed a clockevent and taken over the
duty then the question whether the tick on the current CPU can be stopped
or not is moot. In that case the current CPU would have no clockevent
either, so there would be nothing to keep ticking.

Remove it.

Signed-off-by: Thomas Gleixner 
Acked-by: Frederic Weisbecker 
Link: https://lore.kernel.org/r/20201206212002.725238293@linutronix.de

tick: Remove pointless cpu valid check in hotplug code

2020-12-16T10:26:27+00:00

tick_handover_do_timer() which is invoked when a CPU is unplugged has a
check for cpumask_first(cpu_online_mask) when it tries to hand over the
tick update duty.

Checking the result of cpumask_first() there is pointless because if the
online mask is empty at this point, then this would be the last CPU in the
system going offline, which is impossible. There is always at least one CPU
remaining. If online mask would be really empty then the timer duty would
be the least of the resulting problems.

Remove the well meant check simply because it is pointless and confusing.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Frederic Weisbecker 
Link: https://lore.kernel.org/r/20201206212002.582579516@linutronix.de