user/sven/linux.git/kernel/time, branch v5.4.76

timekeeping: Prevent 32bit truncation in scale64_check_overflow()

2020-10-01T11:17:38Z

[ Upstream commit 4cbbc3a0eeed675449b1a4d080008927121f3da3 ] While unlikely the divisor in scale64_check_overflow() could be >= 32bit in scale64_check_overflow(). do_div() truncates the divisor to 32bit at least on 32bit platforms. Use div64_u64() instead to avoid the truncation to 32-bit. [ tglx: Massaged changelog ] Signed-off-by: Wen Yang Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200120100523.45656-1-wenyang@linux.alibaba.com Signed-off-by: Sasha Levin

random32: update the net random state on interrupt and activity

2020-08-07T07:34:01Z

commit f227e3ec3b5cad859ad15666874405e8c1bbc1d4 upstream. This modifies the first 32 bits out of the 128 bits of a random CPU's net_rand_state on interrupt or CPU activity to complicate remote observations that could lead to guessing the network RNG's internal state. Note that depending on some network devices' interrupt rate moderation or binding, this re-seeding might happen on every packet or even almost never. In addition, with NOHZ some CPUs might not even get timer interrupts, leaving their local state rarely updated, while they are running networked processes making use of the random state. For this reason, we also perform this update in update_process_times() in order to at least update the state when there is user or system activity, since it's the only case we care about. Reported-by: Amit Klein Suggested-by: Linus Torvalds Cc: Eric Dumazet Cc: "Jason A. Donenfeld" Cc: Andy Lutomirski Cc: Kees Cook Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Signed-off-by: Willy Tarreau Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

timer: Fix wheel index calculation on last level

2020-07-22T07:33:14Z

commit e2a71bdea81690b6ef11f4368261ec6f5b6891aa upstream. When an expiration delta falls into the last level of the wheel, that delta has be compared against the maximum possible delay and reduced to fit in if necessary. However instead of comparing the delta against the maximum, the code compares the actual expiry against the maximum. Then instead of fixing the delta to fit in, it sets the maximum delta as the expiry value. This can result in various undesired outcomes, the worst possible one being a timer expiring 15 days ahead to fire immediately. Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel") Signed-off-by: Frederic Weisbecker Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200717140551.29076-2-frederic@kernel.org Signed-off-by: Greg Kroah-Hartman

timer: Prevent base->clk from moving backward

2020-07-22T07:33:13Z

commit 30c66fc30ee7a98c4f3adf5fb7e213b61884474f upstream. When a timer is enqueued with a negative delta (ie: expiry is below base->clk), it gets added to the wheel as expiring now (base->clk). Yet the value that gets stored in base->next_expiry, while calling trigger_dyntick_cpu(), is the initial timer->expires value. The resulting state becomes: base->next_expiry < base->clk On the next timer enqueue, forward_timer_base() may accidentally rewind base->clk. As a possible outcome, timers may expire way too early, the worst case being that the highest wheel levels get spuriously processed again. To prevent from that, make sure that base->next_expiry doesn't get below base->clk. Fixes: a683f390b93f ("timers: Forward the wheel clock whenever possible") Signed-off-by: Frederic Weisbecker Signed-off-by: Thomas Gleixner Reviewed-by: Anna-Maria Behnsen Tested-by: Juri Lelli Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200703010657.2302-1-frederic@kernel.org Signed-off-by: Greg Kroah-Hartman

time/sched_clock: Expire timer in hardirq context

2020-04-17T08:50:02Z

[ Upstream commit 2c8bd58812ee3dbf0d78b566822f7eacd34bdd7b ] To minimize latency, PREEMPT_RT kernels expires hrtimers in preemptible softirq context by default. This can be overriden by marking the timer's expiry with HRTIMER_MODE_HARD. sched_clock_timer is missing this annotation: if its callback is preempted and the duration of the preemption exceeds the wrap around time of the underlying clocksource, sched clock will get out of sync. Mark the sched_clock_timer for expiry in hard interrupt context. Signed-off-by: Ahmed S. Darwish Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200309181529.26558-1-a.darwish@linutronix.de Signed-off-by: Sasha Levin

lib/vdso: Update coarse timekeeper unconditionally

2020-03-05T15:43:49Z

commit 9f24c540f7f8eb3a981528da9a9a636a5bdf5987 upstream. The low resolution parts of the VDSO, i.e.: clock_gettime(CLOCK_*_COARSE), clock_getres(), time() can be used even if there is no VDSO capable clocksource. But if an architecture opts out of the VDSO data update then this information becomes stale. This affects ARM when there is no architected timer available. The lack of update causes userspace to use stale data forever. Make the update of the low resolution parts unconditional and only skip the update of the high resolution parts if the architecture requests it. Fixes: 44f57d788e7d ("timekeeping: Provide a generic update_vsyscall() implementation") Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20200114185946.765577901@linutronix.de Signed-off-by: Greg Kroah-Hartman

lib/vdso: Make __arch_update_vdso_data() logic understandable

2020-03-05T15:43:49Z

commit 9a6b55ac4a44060bcb782baf002859b2a2c63267 upstream. The function name suggests that this is a boolean checking whether the architecture asks for an update of the VDSO data, but it works the other way round. To spare further confusion invert the logic. Fixes: 44f57d788e7d ("timekeeping: Provide a generic update_vsyscall() implementation") Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20200114185946.656652824@linutronix.de Signed-off-by: Greg Kroah-Hartman

alarmtimer: Make alarmtimer platform device child of RTC device

2020-02-24T07:36:57Z

[ Upstream commit c79108bd19a8490315847e0c95ac6526fcd8e770 ] The alarmtimer_suspend() function will fail if an RTC device is on a bus such as SPI or i2c and that RTC device registers and probes after alarmtimer_init() registers and probes the 'alarmtimer' platform device. This is because system wide suspend suspends devices in the reverse order of their probe. When alarmtimer_suspend() attempts to program the RTC for a wakeup it will try to program an RTC device on a bus that has already been suspended. Move the alarmtimer device registration to happen when the RTC which is used for wakeup is registered. Register the 'alarmtimer' platform device as a child of the RTC device too, so that it can be guaranteed that the RTC device won't be suspended when alarmtimer_suspend() is called. Reported-by: Douglas Anderson Signed-off-by: Stephen Boyd Signed-off-by: Thomas Gleixner Reviewed-by: Douglas Anderson Link: https://lore.kernel.org/r/20200124055849.154411-2-swboyd@chromium.org Signed-off-by: Sasha Levin

clocksource: Prevent double add_timer_on() for watchdog_timer

2020-02-11T12:35:54Z

commit febac332a819f0e764aa4da62757ba21d18c182b upstream. Kernel crashes inside QEMU/KVM are observed: kernel BUG at kernel/time/timer.c:1154! BUG_ON(timer_pending(timer) || !timer->function) in add_timer_on(). At the same time another cpu got: general protection fault: 0000 [#1] SMP PTI of poinson pointer 0xdead000000000200 in: __hlist_del at include/linux/list.h:681 (inlined by) detach_timer at kernel/time/timer.c:818 (inlined by) expire_timers at kernel/time/timer.c:1355 (inlined by) __run_timers at kernel/time/timer.c:1686 (inlined by) run_timer_softirq at kernel/time/timer.c:1699 Unfortunately kernel logs are badly scrambled, stacktraces are lost. Printing the timer->function before the BUG_ON() pointed to clocksource_watchdog(). The execution of clocksource_watchdog() can race with a sequence of clocksource_stop_watchdog() .. clocksource_start_watchdog(): expire_timers() detach_timer(timer, true); timer->entry.pprev = NULL; raw_spin_unlock_irq(&base->lock); call_timer_fn clocksource_watchdog() clocksource_watchdog_kthread() or clocksource_unbind() spin_lock_irqsave(&watchdog_lock, flags); clocksource_stop_watchdog(); del_timer(&watchdog_timer); watchdog_running = 0; spin_unlock_irqrestore(&watchdog_lock, flags); spin_lock_irqsave(&watchdog_lock, flags); clocksource_start_watchdog(); add_timer_on(&watchdog_timer, ...); watchdog_running = 1; spin_unlock_irqrestore(&watchdog_lock, flags); spin_lock(&watchdog_lock); add_timer_on(&watchdog_timer, ...); BUG_ON(timer_pending(timer) || !timer->function); timer_pending() -> true BUG() I.e. inside clocksource_watchdog() watchdog_timer could be already armed. Check timer_pending() before calling add_timer_on(). This is sufficient as all operations are synchronized by watchdog_lock. Fixes: 75c5158f70c0 ("timekeeping: Update clocksource with stop_machine") Signed-off-by: Konstantin Khlebnikov Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/158048693917.4378.13823603769948933793.stgit@buzz Signed-off-by: Greg Kroah-Hartman

alarmtimer: Unregister wakeup source when module get fails

2020-02-11T12:35:20Z

commit 6b6d188aae79a630957aefd88ff5c42af6553ee3 upstream. The alarmtimer_rtc_add_device() function creates a wakeup source and then tries to grab a module reference. If that fails the function returns early with an error code, but fails to remove the wakeup source. Cleanup this exit path so there is no dangling wakeup source, which is named 'alarmtime' left allocated which will conflict with another RTC device that may be registered later. Fixes: 51218298a25e ("alarmtimer: Ensure RTC module is not unloaded") Signed-off-by: Stephen Boyd Signed-off-by: Thomas Gleixner Reviewed-by: Douglas Anderson Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200109155910.907-2-swboyd@chromium.org Signed-off-by: Greg Kroah-Hartman