linux.git/kernel/time, branch v6.6.72

ntp: Remove invalid cast in time offset math

2024-12-14T18:59:44+00:00

commit f5807b0606da7ac7c1b74a386b22134ec7702d05 upstream.

Due to an unsigned cast, adjtimex() returns the wrong offest when using
ADJ_MICRO and the offset is negative. In this case a small negative offset
returns approximately 4.29 seconds (~ 2^32/1000 milliseconds) due to the
unsigned cast of the negative offset.

This cast was added when the kernel internal struct timex was changed to
use type long long for the time offset value to address the problem of a
64bit/32bit division on 32bit systems.

The correct cast would have been (s32), which is correct as time_offset can
only be in the range of [INT_MIN..INT_MAX] because the shift constant used
for calculating it is 32. But that's non-obvious.

Remove the cast and use div_s64() to cure the issue.

[ tglx: Fix white space damage, use div_s64() and amend the change log ]

Fixes: ead25417f82e ("timex: use __kernel_timex internally")
Signed-off-by: Marcelo Dalmas 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/SJ0P101MB03687BF7D5A10FD3C49C51E5F42E2@SJ0P101MB0368.NAMP101.PROD.OUTLOOK.COM
Signed-off-by: Greg Kroah-Hartman

time: Fix references to _msecs_to_jiffies() handling of values

2024-12-09T09:31:50+00:00

[ Upstream commit 92b043fd995a63a57aae29ff85a39b6f30cd440c ]

The details about the handling of the "normal" values were moved
to the _msecs_to_jiffies() helpers in commit ca42aaf0c861 ("time:
Refactor msecs_to_jiffies"). However, the same commit still mentioned
__msecs_to_jiffies() in the added documentation.

Thus point to _msecs_to_jiffies() instead.

Fixes: ca42aaf0c861 ("time: Refactor msecs_to_jiffies")
Signed-off-by: Miguel Ojeda 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/20241025110141.157205-2-ojeda@kernel.org
Signed-off-by: Sasha Levin

time: Partially revert cleanup on msecs_to_jiffies() documentation

2024-12-09T09:31:50+00:00

[ Upstream commit b05aefc1f5886c8aece650c9c1639c87b976191a ]

The documentation's intention is to compare msecs_to_jiffies() (first
sentence) with __msecs_to_jiffies() (second sentence), which is what the
original documentation did. One of the cleanups in commit f3cb80804b82
("time: Fix various kernel-doc problems") may have thought the paragraph
was talking about the latter since that is what it is being documented.

Thus revert that part of the change.

Fixes: f3cb80804b82 ("time: Fix various kernel-doc problems")
Signed-off-by: Miguel Ojeda 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/20241025110141.157205-1-ojeda@kernel.org
Signed-off-by: Sasha Levin

posix-clock: posix-clock: Fix unbalanced locking in pc_clock_settime()

2024-11-01T00:58:30+00:00

[ Upstream commit 6e62807c7fbb3c758d233018caf94dfea9c65dbd ]

If get_clock_desc() succeeds, it calls fget() for the clockid's fd,
and get the clk->rwsem read lock, so the error path should release
the lock to make the lock balance and fput the clockid's fd to make
the refcount balance and release the fd related resource.

However the below commit left the error path locked behind resulting in
unbalanced locking. Check timespec64_valid_strict() before
get_clock_desc() to fix it, because the "ts" is not changed
after that.

Fixes: d8794ac20a29 ("posix-clock: Fix missing timespec64 check in pc_clock_settime()")
Acked-by: Richard Cochran 
Signed-off-by: Jinjie Ruan 
Acked-by: Anna-Maria Behnsen 
[pabeni@redhat.com: fixed commit message typo]
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

posix-clock: Fix missing timespec64 check in pc_clock_settime()

2024-10-22T13:46:19+00:00

commit d8794ac20a299b647ba9958f6d657051fc51a540 upstream.

As Andrew pointed out, it will make sense that the PTP core
checked timespec64 struct's tv_sec and tv_nsec range before calling
ptp->info->settime64().

As the man manual of clock_settime() said, if tp.tv_sec is negative or
tp.tv_nsec is outside the range [0..999,999,999], it should return EINVAL,
which include dynamic clocks which handles PTP clock, and the condition is
consistent with timespec64_valid(). As Thomas suggested, timespec64_valid()
only check the timespec is valid, but not ensure that the time is
in a valid range, so check it ahead using timespec64_valid_strict()
in pc_clock_settime() and return -EINVAL if not valid.

There are some drivers that use tp->tv_sec and tp->tv_nsec directly to
write registers without validity checks and assume that the higher layer
has checked it, which is dangerous and will benefit from this, such as
hclge_ptp_settime(), igb_ptp_settime_i210(), _rcar_gen4_ptp_settime(),
and some drivers can remove the checks of itself.

Cc: stable@vger.kernel.org
Fixes: 0606f422b453 ("posix clocks: Introduce dynamic clocks")
Acked-by: Richard Cochran 
Suggested-by: Andrew Lunn 
Suggested-by: Thomas Gleixner 
Signed-off-by: Jinjie Ruan 
Link: https://patch.msgid.link/20241009072302.1754567-2-ruanjinjie@huawei.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

hrtimer: Prevent queuing of hrtimer without a function callback

2024-08-29T15:33:41+00:00

[ Upstream commit 5a830bbce3af16833fe0092dec47b6dd30279825 ]

The hrtimer function callback must not be NULL. It has to be specified by
the call side but it is not validated by the hrtimer code. When a hrtimer
is queued without a function callback, the kernel crashes with a null
pointer dereference when trying to execute the callback in __run_hrtimer().

Introduce a validation before queuing the hrtimer in
hrtimer_start_range_ns().

[anna-maria: Rephrase commit message]

Signed-off-by: Phil Chang 
Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Anna-Maria Behnsen 
Signed-off-by: Sasha Levin

clocksource: Make watchdog and suspend-timing multiplication overflow safe

2024-08-29T15:33:39+00:00

[ Upstream commit d0304569fb019d1bcfbbbce1ce6df6b96f04079b ]

Kernel timekeeping is designed to keep the change in cycles (since the last
timer interrupt) below max_cycles, which prevents multiplication overflow
when converting cycles to nanoseconds. However, if timer interrupts stop,
the clocksource_cyc2ns() calculation will eventually overflow.

Add protection against that. Simplify by folding together
clocksource_delta() and clocksource_cyc2ns() into cycles_to_nsec_safe().
Check against max_cycles, falling back to a slower higher precision
calculation.

Suggested-by: Thomas Gleixner 
Signed-off-by: Adrian Hunter 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20240325064023.2997-20-adrian.hunter@intel.com
Signed-off-by: Sasha Levin

tick: Move got_idle_tick away from common flags

2024-08-29T15:33:35+00:00

[ Upstream commit 3ce74f1a8566dbbc9774f85fb0ce781fe290fd32 ]

tick_nohz_idle_got_tick() is called by cpuidle_reflect() within the idle
loop with interrupts enabled. This function modifies the struct
tick_sched's bitfield "got_idle_tick". However this bitfield is stored
within the same mask as other bitfields that can be modified from
interrupts.

Fortunately so far it looks like the only race that can happen is while
writing ->got_idle_tick to 0, an interrupt fires and writes the
->idle_active field to 0. It's then possible that the interrupted write
to ->got_idle_tick writes back the old value of ->idle_active back to 1.

However if that happens, the worst possible outcome is that the time
spent between that interrupt and the upcoming call to
tick_nohz_idle_exit() is accounted as idle, which is negligible quantity.

Still all the bitfield writes within this struct tick_sched's shadow
mask should be IRQ-safe. Therefore move this bitfield out to its own
storage to avoid further suprises.

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20240225225508.11587-12-frederic@kernel.org
Signed-off-by: Sasha Levin

hrtimer: Select housekeeping CPU during migration

2024-08-29T15:33:34+00:00

[ Upstream commit 56c2cb10120894be40c40a9bf0ce798da14c50f6 ]

During CPU-down hotplug, hrtimers may migrate to isolated CPUs,
compromising CPU isolation.

Address this issue by masking valid CPUs for hrtimers using
housekeeping_cpumask(HK_TYPE_TIMER).

Suggested-by: Waiman Long 
Signed-off-by: Costa Shulyupin 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Waiman Long 
Link: https://lore.kernel.org/r/20240222200856.569036-1-costa.shul@redhat.com
Signed-off-by: Sasha Levin

timekeeping: Fix bogus clock_was_set() invocation in do_adjtimex()

2024-08-14T11:58:57+00:00

commit 5916be8a53de6401871bdd953f6c60237b47d6d3 upstream.

The addition of the bases argument to clock_was_set() fixed up all call
sites correctly except for do_adjtimex(). This uses CLOCK_REALTIME
instead of CLOCK_SET_WALL as argument. CLOCK_REALTIME is 0.

As a result the effect of that clock_was_set() notification is incomplete
and might result in timers expiring late because the hrtimer code does
not re-evaluate the affected clock bases.

Use CLOCK_SET_WALL instead of CLOCK_REALTIME to tell the hrtimers code
which clock bases need to be re-evaluated.

Fixes: 17a1b8826b45 ("hrtimer: Add bases argument to clock_was_set()")
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/877ccx7igo.ffs@tglx
Signed-off-by: Greg Kroah-Hartman