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* nohz: Fix collision between tick and other hrtimersFrederic Weisbecker2017-01-112-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the tick is stopped and an interrupt occurs afterward, we check on that interrupt exit if the next tick needs to be rescheduled. If it doesn't need any update, we don't want to do anything. In order to check if the tick needs an update, we compare it against the clockevent device deadline. Now that's a problem because the clockevent device is at a lower level than the tick itself if it is implemented on top of hrtimer. Every hrtimer share this clockevent device. So comparing the next tick deadline against the clockevent device deadline is wrong because the device may be programmed for another hrtimer whose deadline collides with the tick. As a result we may end up not reprogramming the tick accidentally. In a worst case scenario under full dynticks mode, the tick stops firing as it is supposed to every 1hz, leaving /proc/stat stalled: Task in a full dynticks CPU ---------------------------- * hrtimer A is queued 2 seconds ahead * the tick is stopped, scheduled 1 second ahead * tick fires 1 second later * on tick exit, nohz schedules the tick 1 second ahead but sees the clockevent device is already programmed to that deadline, fooled by hrtimer A, the tick isn't rescheduled. * hrtimer A is cancelled before its deadline * tick never fires again until an interrupt happens... In order to fix this, store the next tick deadline to the tick_sched local structure and reuse that value later to check whether we need to reprogram the clock after an interrupt. On the other hand, ts->sleep_length still wants to know about the next clock event and not just the tick, so we want to improve the related comment to avoid confusion. Reported-by: James Hartsock <hartsjc@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Rik van Riel <riel@redhat.com> Link: http://lkml.kernel.org/r/1483539124-5693-1-git-send-email-fweisbec@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* ktime: Cleanup ktime_set() usageThomas Gleixner2016-12-254-6/+6
| | | | | | | | | | ktime_set(S,N) was required for the timespec storage type and is still useful for situations where a Seconds and Nanoseconds part of a time value needs to be converted. For anything where the Seconds argument is 0, this is pointless and can be replaced with a simple assignment. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
* ktime: Get rid of the unionThomas Gleixner2016-12-2511-83/+83
| | | | | | | | | | | | | | | ktime is a union because the initial implementation stored the time in scalar nanoseconds on 64 bit machine and in a endianess optimized timespec variant for 32bit machines. The Y2038 cleanup removed the timespec variant and switched everything to scalar nanoseconds. The union remained, but become completely pointless. Get rid of the union and just keep ktime_t as simple typedef of type s64. The conversion was done with coccinelle and some manual mopping up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
* clocksource: Use a plain u64 instead of cycle_tThomas Gleixner2016-12-255-39/+36
| | | | | | | | | | | | | | | | | | | | | There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org>
* Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds2016-12-248-8/+8
| | | | | | | | | | | | | This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds2016-12-181-0/+3
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Thomas Gleixner: "Prevent NULL pointer dereferencing in the tick broadcast code. Old bug, which got unearthed by the hotplug ordering problem" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick/broadcast: Prevent NULL pointer dereference
| * tick/broadcast: Prevent NULL pointer dereferenceThomas Gleixner2016-12-151-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a disfunctional timer, e.g. dummy timer, is installed, the tick core tries to setup the broadcast timer. If no broadcast device is installed, the kernel crashes with a NULL pointer dereference in tick_broadcast_setup_oneshot() because the function has no sanity check. Reported-by: Mason <slash.tmp@free.fr> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Richard Cochran <rcochran@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org>, Cc: Sebastian Frias <sf84@laposte.net> Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com> Cc: Robin Murphy <robin.murphy@arm.com> Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
* | posix-timers: give lazy compilers some help optimizing code awayNicolas Pitre2016-12-141-1/+2
|/ | | | | | | | | | | | | | | | | | The OpenRISC compiler (so far) fails to optimize away a large portion of code containing a reference to posix_timer_event in alarmtimer.c when CONFIG_POSIX_TIMERS is unset. Let's give it a direct clue to let the build succeed. This fixes [linux-next:master 6682/7183] alarmtimer.c:undefined reference to `posix_timer_event' reported by kbuild test robot. Signed-off-by: Nicolas Pitre <nico@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2016-12-128-94/+275
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "The time/timekeeping/timer folks deliver with this update: - Fix a reintroduced signed/unsigned issue and cleanup the whole signed/unsigned mess in the timekeeping core so this wont happen accidentaly again. - Add a new trace clock based on boot time - Prevent injection of random sleep times when PM tracing abuses the RTC for storage - Make posix timers configurable for real tiny systems - Add tracepoints for the alarm timer subsystem so timer based suspend wakeups can be instrumented - The usual pile of fixes and updates to core and drivers" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) timekeeping: Use mul_u64_u32_shr() instead of open coding it timekeeping: Get rid of pointless typecasts timekeeping: Make the conversion call chain consistently unsigned timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion alarmtimer: Add tracepoints for alarm timers trace: Update documentation for mono, mono_raw and boot clock trace: Add an option for boot clock as trace clock timekeeping: Add a fast and NMI safe boot clock timekeeping/clocksource_cyc2ns: Document intended range limitation timekeeping: Ignore the bogus sleep time if pm_trace is enabled selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous" clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map() arm64: dts: rockchip: Arch counter doesn't tick in system suspend clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend posix-timers: Make them configurable posix_cpu_timers: Move the add_device_randomness() call to a proper place timer: Move sys_alarm from timer.c to itimer.c ptp_clock: Allow for it to be optional Kconfig: Regenerate *.c_shipped files after previous changes ...
| * timekeeping: Use mul_u64_u32_shr() instead of open coding itThomas Gleixner2016-12-091-21/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The resume code must deal with a clocksource delta which is potentially big enough to overflow the 64bit mult. Replace the open coded handling with the proper function. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.921674404@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping: Get rid of pointless typecastsThomas Gleixner2016-12-091-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cycle_t is defined as u64, so casting it to u64 is a pointless and confusing exercise. cycle_t should simply go away and be replaced with a plain u64 to avoid further confusion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.844699737@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping: Make the conversion call chain consistently unsignedThomas Gleixner2016-12-091-13/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Propagating a unsigned value through signed variables and functions makes absolutely no sense and is just prone to (re)introduce subtle signed vs. unsigned issues as happened recently. Clean it up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.765843099@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversionThomas Gleixner2016-12-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The clocksource delta to nanoseconds conversion is using signed math, but the delta is unsigned. This makes the conversion space smaller than necessary and in case of a multiplication overflow the conversion can become negative. The conversion is done with scaled math: s64 nsec_delta = ((s64)clkdelta * clk->mult) >> clk->shift; Shifting a signed integer right obvioulsy preserves the sign, which has interesting consequences: - Time jumps backwards - __iter_div_u64_rem() which is used in one of the calling code pathes will take forever to piecewise calculate the seconds/nanoseconds part. This has been reported by several people with different scenarios: David observed that when stopping a VM with a debugger: "It was essentially the stopped by debugger case. I forget exactly why, but the guest was being explicitly stopped from outside, it wasn't just scheduling lag. I think it was something in the vicinity of 10 minutes stopped." When lifting the stop the machine went dead. The stopped by debugger case is not really interesting, but nevertheless it would be a good thing not to die completely. But this was also observed on a live system by Liav: "When the OS is too overloaded, delta will get a high enough value for the msb of the sum delta * tkr->mult + tkr->xtime_nsec to be set, and so after the shift the nsec variable will gain a value similar to 0xffffffffff000000." Unfortunately this has been reintroduced recently with commit 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation"). It had been fixed a year ago already in commit 35a4933a8959 ("time: Avoid signed overflow in timekeeping_get_ns()"). Though it's not surprising that the issue has been reintroduced because the function itself and the whole call chain uses s64 for the result and the propagation of it. The change in this recent commit is subtle: s64 nsec; - nsec = (d * m + n) >> s: + nsec = d * m + n; + nsec >>= s; d being type of cycle_t adds another level of obfuscation. This wouldn't have happened if the previous change to unsigned computation would have made the 'nsec' variable u64 right away and a follow up patch had cleaned up the whole call chain. There have been patches submitted which basically did a revert of the above patch leaving everything else unchanged as signed. Back to square one. This spawned a admittedly pointless discussion about potential users which rely on the unsigned behaviour until someone pointed out that it had been fixed before. The changelogs of said patches added further confusion as they made finally false claims about the consequences for eventual users which expect signed results. Despite delta being cycle_t, aka. u64, it's very well possible to hand in a signed negative value and the signed computation will happily return the correct result. But nobody actually sat down and analyzed the code which was added as user after the propably unintended signed conversion. Though in sensitive code like this it's better to analyze it proper and make sure that nothing relies on this than hunting the subtle wreckage half a year later. After analyzing all call chains it stands that no caller can hand in a negative value (which actually would work due to the s64 cast) and rely on the signed math to do the right thing. Change the conversion function to unsigned math. The conversion of all call chains is done in a follow up patch. This solves the starvation issue, which was caused by the negative result, but it does not solve the underlying problem. It merily procrastinates it. When the timekeeper update is deferred long enough that the unsigned multiplication overflows, then time going backwards is observable again. It does neither solve the issue of clocksources with a small counter width which will wrap around possibly several times and cause random time stamps to be generated. But those are usually not found on systems used for virtualization, so this is likely a non issue. I took the liberty to claim authorship for this simply because analyzing all callsites and writing the changelog took substantially more time than just making the simple s/s64/u64/ change and ignore the rest. Fixes: 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation") Reported-by: David Gibson <david@gibson.dropbear.id.au> Reported-by: Liav Rehana <liavr@mellanox.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20161208204228.688545601@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * alarmtimer: Add tracepoints for alarm timersBaolin Wang2016-12-011-10/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Alarm timers are one of the mechanisms to wake up a system from suspend, but there exist no tracepoints to analyse which process/thread armed an alarmtimer. Add tracepoints for start/cancel/expire of individual alarm timers and one for tracing the suspend time decision when to resume the system. The following trace excerpt illustrates the new mechanism: Binder:3292_2-3304 [000] d..2 149.981123: alarmtimer_cancel: alarmtimer:ffffffc1319a7800 type:REALTIME expires:1325463120000000000 now:1325376810370370245 Binder:3292_2-3304 [000] d..2 149.981136: alarmtimer_start: alarmtimer:ffffffc1319a7800 type:REALTIME expires:1325376840000000000 now:1325376810370384591 Binder:3292_9-3953 [000] d..2 150.212991: alarmtimer_cancel: alarmtimer:ffffffc1319a5a00 type:BOOTTIME expires:179552000000 now:150154008122 Binder:3292_9-3953 [000] d..2 150.213006: alarmtimer_start: alarmtimer:ffffffc1319a5a00 type:BOOTTIME expires:179551000000 now:150154025622 system_server-3000 [002] ...1 162.701940: alarmtimer_suspend: alarmtimer type:REALTIME expires:1325376840000000000 The wakeup time which is selected at suspend time allows to map it back to the task arming the timer: Binder:3292_2. [ tglx: Store alarm timer expiry time instead of some useless RTC relative information, add proper type information for wakeups which are handled via the clock_nanosleep/freezer and massage the changelog. ] Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Link: http://lkml.kernel.org/r/1480372524-15181-5-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping: Add a fast and NMI safe boot clockJoel Fernandes2016-11-291-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This boot clock can be used as a tracing clock and will account for suspend time. To keep it NMI safe since we're accessing from tracing, we're not using a separate timekeeper with updates to monotonic clock and boot offset protected with seqlocks. This has the following minor side effects: (1) Its possible that a timestamp be taken after the boot offset is updated but before the timekeeper is updated. If this happens, the new boot offset is added to the old timekeeping making the clock appear to update slightly earlier: CPU 0 CPU 1 timekeeping_inject_sleeptime64() __timekeeping_inject_sleeptime(tk, delta); timestamp(); timekeeping_update(tk, TK_CLEAR_NTP...); (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be partially updated. Since the tk->offs_boot update is a rare event, this should be a rare occurrence which postprocessing should be able to handle. Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1480372524-15181-6-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * posix-timers: Make them configurableNicolas Pitre2016-11-164-5/+137
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some embedded systems have no use for them. This removes about 25KB from the kernel binary size when configured out. Corresponding syscalls are routed to a stub logging the attempt to use those syscalls which should be enough of a clue if they were disabled without proper consideration. They are: timer_create, timer_gettime: timer_getoverrun, timer_settime, timer_delete, clock_adjtime, setitimer, getitimer, alarm. The clock_settime, clock_gettime, clock_getres and clock_nanosleep syscalls are replaced by simple wrappers compatible with CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only which should cover the vast majority of use cases with very little code. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Richard Cochran <richardcochran@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Michal Marek <mmarek@suse.com> Cc: Edward Cree <ecree@solarflare.com> Link: http://lkml.kernel.org/r/1478841010-28605-7-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * posix_cpu_timers: Move the add_device_randomness() call to a proper placeNicolas Pitre2016-11-161-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no logical relation between add_device_randomness() and posix_cpu_timers_exit(). Let's move the former to where the later is called. This way, when posix-cpu-timers.c is compiled out, there is no need to worry about not losing a call to add_device_randomness(). Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Richard Cochran <richardcochran@gmail.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Michal Marek <mmarek@suse.com> Cc: Edward Cree <ecree@solarflare.com> Link: http://lkml.kernel.org/r/1478841010-28605-6-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timer: Move sys_alarm from timer.c to itimer.cNicolas Pitre2016-11-162-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the only user of alarm_setitimer to itimer.c where it is defined. This allows for making alarm_setitimer static, and dropping it from the build when __ARCH_WANT_SYS_ALARM is not defined. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Richard Cochran <richardcochran@gmail.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Michal Marek <mmarek@suse.com> Cc: Edward Cree <ecree@solarflare.com> Link: http://lkml.kernel.org/r/1478841010-28605-5-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timers: Fix documentation for schedule_timeout() and similarDouglas Anderson2016-10-262-10/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The documentation for schedule_timeout(), schedule_hrtimeout(), and schedule_hrtimeout_range() all claim that the routines couldn't possibly return early if the task state was TASK_UNINTERRUPTIBLE. This is simply not true since wake_up_process() will cause those routines to exit early. We cannot make schedule_[hr]timeout() loop until the timeout expires if the task state is uninterruptible because we have users which rely on the existing and designed behaviour. Make the documentation match the (correct) implementation. schedule_hrtimeout() returns -EINTR even when a uninterruptible task was woken up. This might look strange, but making the return code depend on the state is too much of an effort as it would affect all the call sites. There is no value in doing so, but we spell it out clearly in the documentation. Suggested-by: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: huangtao@rock-chips.com Cc: heiko@sntech.de Cc: broonie@kernel.org Cc: briannorris@chromium.org Cc: Andreas Mohr <andi@lisas.de> Cc: linux-rockchip@lists.infradead.org Cc: tony.xie@rock-chips.com Cc: John Stultz <john.stultz@linaro.org> Cc: linux@roeck-us.net Cc: tskd08@gmail.com Link: http://lkml.kernel.org/r/1477065531-30342-2-git-send-email-dianders@chromium.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timers: Fix usleep_range() in the context of wake_up_process()Douglas Anderson2016-10-261-12/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Users of usleep_range() expect that it will _never_ return in less time than the minimum passed parameter. However, nothing in the code ensures this, when the sleeping task is woken by wake_up_process() or any other mechanism which can wake a task from uninterruptible state. Neither usleep_range() nor schedule_hrtimeout_range*() have any protection against wakeups. schedule_hrtimeout_range*() is designed this way despite the fact that the API documentation does not mention it. msleep() already has code to handle this case since it will loop as long as there was still time left. usleep_range() has no such loop, add it. Presumably this problem was not detected before because usleep_range() is only used in a few places and the function is mostly used in contexts which are not exposed to wakeups of any form. An effort was made to look for users relying on the old behavior by looking for usleep_range() in the same file as wake_up_process(). No problems were found by this search, though it is conceivable that someone could have put the sleep and wakeup in two different files. An effort was made to ask several upstream maintainers if they were aware of people relying on wake_up_process() to wake up usleep_range(). No maintainers were aware of that but they were aware of many people relying on usleep_range() never returning before the minimum. Reported-by: Tao Huang <huangtao@rock-chips.com> Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: heiko@sntech.de Cc: broonie@kernel.org Cc: briannorris@chromium.org Cc: Andreas Mohr <andi@lisas.de> Cc: linux-rockchip@lists.infradead.org Cc: tony.xie@rock-chips.com Cc: John Stultz <john.stultz@linaro.org> Cc: djkurtz@chromium.org Cc: linux@roeck-us.net Cc: tskd08@gmail.com Link: http://lkml.kernel.org/r/1477065531-30342-1-git-send-email-dianders@chromium.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds2016-12-121-19/+14
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull smp hotplug updates from Thomas Gleixner: "This is the final round of converting the notifier mess to the state machine. The removal of the notifiers and the related infrastructure will happen around rc1, as there are conversions outstanding in other trees. The whole exercise removed about 2000 lines of code in total and in course of the conversion several dozen bugs got fixed. The new mechanism allows to test almost every hotplug step standalone, so usage sites can exercise all transitions extensively. There is more room for improvement, like integrating all the pointlessly different architecture mechanisms of synchronizing, setting cpus online etc into the core code" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits) tracing/rb: Init the CPU mask on allocation soc/fsl/qbman: Convert to hotplug state machine soc/fsl/qbman: Convert to hotplug state machine zram: Convert to hotplug state machine KVM/PPC/Book3S HV: Convert to hotplug state machine arm64/cpuinfo: Convert to hotplug state machine arm64/cpuinfo: Make hotplug notifier symmetric mm/compaction: Convert to hotplug state machine iommu/vt-d: Convert to hotplug state machine mm/zswap: Convert pool to hotplug state machine mm/zswap: Convert dst-mem to hotplug state machine mm/zsmalloc: Convert to hotplug state machine mm/vmstat: Convert to hotplug state machine mm/vmstat: Avoid on each online CPU loops mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead() tracing/rb: Convert to hotplug state machine oprofile/nmi timer: Convert to hotplug state machine net/iucv: Use explicit clean up labels in iucv_init() x86/pci/amd-bus: Convert to hotplug state machine x86/oprofile/nmi: Convert to hotplug state machine ...
| * | sched/nohz: Convert to hotplug state machineSebastian Andrzej Siewior2016-11-221-19/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Install the callbacks via the state machine. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: rt@linuxtronix.de Link: http://lkml.kernel.org/r/20161117183541.8588-14-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2016-12-121-2/+2
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main scheduler changes in this cycle were: - support Intel Turbo Boost Max Technology 3.0 (TBM3) by introducig a notion of 'better cores', which the scheduler will prefer to schedule single threaded workloads on. (Tim Chen, Srinivas Pandruvada) - enhance the handling of asymmetric capacity CPUs further (Morten Rasmussen) - improve/fix load handling when moving tasks between task groups (Vincent Guittot) - simplify and clean up the cputime code (Stanislaw Gruszka) - improve mass fork()ed task spread a.k.a. hackbench speedup (Vincent Guittot) - make struct kthread kmalloc()ed and related fixes (Oleg Nesterov) - add uaccess atomicity debugging (when using access_ok() in the wrong context), under CONFIG_DEBUG_ATOMIC_SLEEP=y (Peter Zijlstra) - implement various fixes, cleanups and other enhancements (Daniel Bristot de Oliveira, Martin Schwidefsky, Rafael J. Wysocki)" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) sched/core: Use load_avg for selecting idlest group sched/core: Fix find_idlest_group() for fork kthread: Don't abuse kthread_create_on_cpu() in __kthread_create_worker() kthread: Don't use to_live_kthread() in kthread_[un]park() kthread: Don't use to_live_kthread() in kthread_stop() Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function" kthread: Make struct kthread kmalloc'ed x86/uaccess, sched/preempt: Verify access_ok() context sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO x86/sched: Use #include <linux/mutex.h> instead of #include <asm/mutex.h> cpufreq/intel_pstate: Use CPPC to get max performance acpi/bus: Set _OSC for diverse core support acpi/bus: Enable HWP CPPC objects x86/sched: Add SD_ASYM_PACKING flags to x86 ITMT CPU x86/sysctl: Add sysctl for ITMT scheduling feature x86: Enable Intel Turbo Boost Max Technology 3.0 x86/topology: Define x86's arch_update_cpu_topology sched: Extend scheduler's asym packing sched/fair: Clean up the tunable parameter definitions ...
| * | | sched/cputime: Simplify task_cputime()Stanislaw Gruszka2016-11-151-2/+2
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now since fetch_task_cputime() has no other users than task_cputime(), its code could be used directly in task_cputime(). Moreover since only 2 task_cputime() calls of 17 use a NULL argument, we can add dummy variables to those calls and remove NULL checks from task_cputimes(). Also remove NULL checks from task_cputimes_scaled(). Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1479175612-14718-5-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* / / clocksource: export the clocks_calc_mult_shift to use by timestamp codeMurali Karicheri2016-12-071-0/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The CPSW CPTS driver is capable of doing timestamping on tx/rx packets and requires to know mult and shift factors for timestamp conversion from raw value to nanoseconds (ptp clock). Now these mult and shift factors are calculated manually and provided through DT, which makes very hard to support of a lot number of platforms, especially if CPTS refclk is not the same for some kind of boards and depends on efuse settings (Keystone 2 platforms). Hence, export clocks_calc_mult_shift() to allow drivers like CPSW CPTS (and other ptp drivesr) to benefit from automaitc calculation of mult and shift factors. Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* | timers: Prevent base clock corruption when forwardingThomas Gleixner2016-10-251-13/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a timer is enqueued we try to forward the timer base clock. This mechanism has two issues: 1) Forwarding a remote base unlocked The forwarding function is called from get_target_base() with the current timer base lock held. But if the new target base is a different base than the current base (can happen with NOHZ, sigh!) then the forwarding is done on an unlocked base. This can lead to corruption of base->clk. Solution is simple: Invoke the forwarding after the target base is locked. 2) Possible corruption due to jiffies advancing This is similar to the issue in get_net_timer_interrupt() which was fixed in the previous patch. jiffies can advance between check and assignement and therefore advancing base->clk beyond the next expiry value. So we need to read jiffies into a local variable once and do the checks and assignment with the local copy. Fixes: a683f390b93f("timers: Forward the wheel clock whenever possible") Reported-by: Ashton Holmes <scoopta@gmail.com> Reported-by: Michael Thayer <michael.thayer@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Michal Necasek <michal.necasek@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: knut.osmundsen@oracle.com Cc: stable@vger.kernel.org Cc: stern@rowland.harvard.edu Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161022110552.253640125@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | timers: Prevent base clock rewind when forwarding clockThomas Gleixner2016-10-251-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ashton and Michael reported, that kernel versions 4.8 and later suffer from USB timeouts which are caused by the timer wheel rework. This is caused by a bug in the base clock forwarding mechanism, which leads to timers expiring early. The scenario which leads to this is: run_timers() while (jiffies >= base->clk) { collect_expired_timers(); base->clk++; expire_timers(); } So base->clk = jiffies + 1. Now the cpu goes idle: idle() get_next_timer_interrupt() nextevt = __next_time_interrupt(); if (time_after(nextevt, base->clk)) base->clk = jiffies; jiffies has not advanced since run_timers(), so this assignment effectively decrements base->clk by one. base->clk is the index into the timer wheel arrays. So let's assume the following state after the base->clk increment in run_timers(): jiffies = 0 base->clk = 1 A timer gets enqueued with an expiry delta of 63 ticks (which is the case with the USB timeout and HZ=250) so the resulting bucket index is: base->clk + delta = 1 + 63 = 64 The timer goes into the first wheel level. The array size is 64 so it ends up in bucket 0, which is correct as it takes 63 ticks to advance base->clk to index into bucket 0 again. If the cpu goes idle before jiffies advance, then the bug in the forwarding mechanism sets base->clk back to 0, so the next invocation of run_timers() at the next tick will index into bucket 0 and therefore expire the timer 62 ticks too early. Instead of blindly setting base->clk to jiffies we must make the forwarding conditional on jiffies > base->clk, but we cannot use jiffies for this as we might run into the following issue: if (time_after(jiffies, base->clk) { if (time_after(nextevt, base->clk)) base->clk = jiffies; jiffies can increment between the check and the assigment far enough to advance beyond nextevt. So we need to use a stable value for checking. get_next_timer_interrupt() has the basej argument which is the jiffies value snapshot taken in the calling code. So we can just that. Thanks to Ashton for bisecting and providing trace data! Fixes: a683f390b93f ("timers: Forward the wheel clock whenever possible") Reported-by: Ashton Holmes <scoopta@gmail.com> Reported-by: Michael Thayer <michael.thayer@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Michal Necasek <michal.necasek@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: knut.osmundsen@oracle.com Cc: stable@vger.kernel.org Cc: stern@rowland.harvard.edu Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161022110552.175308322@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | timers: Lock base for same bucket optimizationThomas Gleixner2016-10-251-11/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linus stumbled over the unlocked modification of the timer expiry value in mod_timer() which is an optimization for timers which stay in the same bucket - due to the bucket granularity - despite their expiry time getting updated. The optimization itself still makes sense even if we take the lock, because in case that the bucket stays the same, we avoid the pointless queue/enqueue dance. Make the check and the modification of timer->expires protected by the base lock and shuffle the remaining code around so we can keep the lock held when we actually have to requeue the timer to a different bucket. Fixes: f00c0afdfa62 ("timers: Implement optimization for same expiry time in mod_timer()") Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610241711220.4983@nanos Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org>
* | timers: Plug locking race vs. timer migrationThomas Gleixner2016-10-251-1/+8
|/ | | | | | | | | | | | | | | | | | Linus noticed that lock_timer_base() lacks a READ_ONCE() for accessing the timer flags. As a consequence the compiler is allowed to reload the flags between the initial check for TIMER_MIGRATION and the following timer base computation and the spin lock of the base. While this has not been observed (yet), we need to make sure that it never happens. Fixes: 0eeda71bc30d ("timer: Replace timer base by a cpu index") Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610241711220.4983@nanos Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org>
* alarmtimer: Remove unused but set variableTobias Klauser2016-10-171-2/+0
| | | | | | | | | | | | | | Remove the set but unused variable base in alarm_clock_get to fix the following warning when building with 'W=1': kernel/time/alarmtimer.c: In function ‘alarm_timer_create’: kernel/time/alarmtimer.c:545:21: warning: variable ‘base’ set but not used [-Wunused-but-set-variable] Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161017094702.10873-1-tklauser@distanz.ch Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge tag 'gcc-plugins-v4.9-rc1' of ↵Linus Torvalds2016-10-151-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc plugins update from Kees Cook: "This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals" * tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: latent_entropy: Mark functions with __latent_entropy gcc-plugins: Add latent_entropy plugin
| * latent_entropy: Mark functions with __latent_entropyEmese Revfy2016-10-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The __latent_entropy gcc attribute can be used only on functions and variables. If it is on a function then the plugin will instrument it for gathering control-flow entropy. If the attribute is on a variable then the plugin will initialize it with random contents. The variable must be an integer, an integer array type or a structure with integer fields. These specific functions have been selected because they are init functions (to help gather boot-time entropy), are called at unpredictable times, or they have variable loops, each of which provide some level of latent entropy. Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: expanded commit message] Signed-off-by: Kees Cook <keescook@chromium.org>
* | timekeeping: Fix __ktime_get_fast_ns() regressionJohn Stultz2016-10-051-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit 27727df240c7 ("Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING"), I changed the logic to open-code the timekeeping_get_ns() function, but I forgot to include the unit conversion from cycles to nanoseconds, breaking the function's output, which impacts users like perf. This results in bogus perf timestamps like: swapper 0 [000] 253.427536: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426573: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426687: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426800: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.426905: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427022: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427127: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427239: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427346: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 254.427463: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 255.426572: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) Instead of more reasonable expected timestamps like: swapper 0 [000] 39.953768: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.064839: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.175956: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.287103: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.398217: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.509324: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.620437: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.731546: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.842654: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 40.953772: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) swapper 0 [000] 41.064881: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms]) Add the proper use of timekeeping_delta_to_ns() to convert the cycle delta to nanoseconds as needed. Thanks to Brendan and Alexei for finding this quickly after the v4.8 release. Unfortunately the problematic commit has landed in some -stable trees so they'll need this fix as well. Many apologies for this mistake. I'll be looking to add a perf-clock sanity test to the kselftest timers tests soon. Fixes: 27727df240c7 "timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING" Reported-by: Brendan Gregg <bgregg@netflix.com> Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Tested-and-reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable <stable@vger.kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1475636148-26539-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | tick/nohz: Prevent stopping the tick on an offline CPUWanpeng Li2016-09-131-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | can_stop_full_tick() has no check for offline cpus. So it allows to stop the tick on an offline cpu from the interrupt return path, which is wrong and subsequently makes irq_work_needs_cpu() warn about being called for an offline cpu. Commit f7ea0fd639c2c4 ("tick: Don't invoke tick_nohz_stop_sched_tick() if the cpu is offline") added prevention for can_stop_idle_tick(), but forgot to do the same in can_stop_full_tick(). Add it. [ tglx: Massaged changelog ] Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1473245473-4463-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'linus' into timers/core, to refresh the branchIngo Molnar2016-09-081-1/+2
|\| | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * tick/nohz: Fix softlockup on scheduler stalls in kvm guestWanpeng Li2016-09-021-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tick_nohz_start_idle() is prevented to be called if the idle tick can't be stopped since commit 1f3b0f8243cb934 ("tick/nohz: Optimize nohz idle enter"). As a result, after suspend/resume the host machine, full dynticks kvm guest will softlockup: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 26s! [swapper/0:0] Call Trace: default_idle+0x31/0x1a0 arch_cpu_idle+0xf/0x20 default_idle_call+0x2a/0x50 cpu_startup_entry+0x39b/0x4d0 rest_init+0x138/0x140 ? rest_init+0x5/0x140 start_kernel+0x4c1/0x4ce ? set_init_arg+0x55/0x55 ? early_idt_handler_array+0x120/0x120 x86_64_start_reservations+0x24/0x26 x86_64_start_kernel+0x142/0x14f In addition, cat /proc/stat | grep cpu in guest or host: cpu 398 16 5049 15754 5490 0 1 46 0 0 cpu0 206 5 450 0 0 0 1 14 0 0 cpu1 81 0 3937 3149 1514 0 0 9 0 0 cpu2 45 6 332 6052 2243 0 0 11 0 0 cpu3 65 2 328 6552 1732 0 0 11 0 0 The idle and iowait states are weird 0 for cpu0(housekeeping). The bug is present in both guest and host kernels, and they both have cpu0's idle and iowait states issue, however, host kernel's suspend/resume path etc will touch watchdog to avoid the softlockup. - The watchdog will not be touched in tick_nohz_stop_idle path (need be touched since the scheduler stall is expected) if idle_active flags are not detected. - The idle and iowait states will not be accounted when exit idle loop (resched or interrupt) if idle start time and idle_active flags are not set. This patch fixes it by reverting commit 1f3b0f8243cb934 since can't stop idle tick doesn't mean can't be idle. Fixes: 1f3b0f8243cb934 ("tick/nohz: Optimize nohz idle enter") Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Sanjeev Yadav<sanjeev.yadav@spreadtrum.com> Cc: Gaurav Jindal<gaurav.jindal@spreadtrum.com> Cc: stable@vger.kernel.org Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/1472798303-4154-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | time: Avoid undefined behaviour in ktime_add_safe()Vegard Nossum2016-08-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I ran into this: ================================================================================ UBSAN: Undefined behaviour in kernel/time/hrtimer.c:310:16 signed integer overflow: 9223372036854775807 + 50000 cannot be represented in type 'long long int' CPU: 2 PID: 4798 Comm: trinity-c2 Not tainted 4.8.0-rc1+ #91 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 0000000000000000 ffff88010ce6fb88 ffffffff82344740 0000000041b58ab3 ffffffff84f97a20 ffffffff82344694 ffff88010ce6fbb0 ffff88010ce6fb60 000000000000c350 ffff88010ce6f968 dffffc0000000000 ffffffff857bc320 Call Trace: [<ffffffff82344740>] dump_stack+0xac/0xfc [<ffffffff82344694>] ? _atomic_dec_and_lock+0xc4/0xc4 [<ffffffff8242df78>] ubsan_epilogue+0xd/0x8a [<ffffffff8242e6b4>] handle_overflow+0x202/0x23d [<ffffffff8242e4b2>] ? val_to_string.constprop.6+0x11e/0x11e [<ffffffff8236df71>] ? timerqueue_add+0x151/0x410 [<ffffffff81485c48>] ? hrtimer_start_range_ns+0x3b8/0x1380 [<ffffffff81795631>] ? memset+0x31/0x40 [<ffffffff8242e6fd>] __ubsan_handle_add_overflow+0xe/0x10 [<ffffffff81488ac9>] hrtimer_nanosleep+0x5d9/0x790 [<ffffffff814884f0>] ? hrtimer_init_sleeper+0x80/0x80 [<ffffffff813a9ffb>] ? __might_sleep+0x5b/0x260 [<ffffffff8148be10>] common_nsleep+0x20/0x30 [<ffffffff814906c7>] SyS_clock_nanosleep+0x197/0x210 [<ffffffff81490530>] ? SyS_clock_getres+0x150/0x150 [<ffffffff823c7113>] ? __this_cpu_preempt_check+0x13/0x20 [<ffffffff8162ef60>] ? __context_tracking_exit.part.3+0x30/0x1b0 [<ffffffff81490530>] ? SyS_clock_getres+0x150/0x150 [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0 [<ffffffff845f85aa>] entry_SYSCALL64_slow_path+0x25/0x25 ================================================================================ Add a new ktime_add_unsafe() helper which doesn't check for overflow, but doesn't throw a UBSAN warning when it does overflow either. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
* | time: Avoid undefined behaviour in timespec64_add_safe()Vegard Nossum2016-08-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I ran into this: ================================================================================ UBSAN: Undefined behaviour in kernel/time/time.c:783:2 signed integer overflow: 5273 + 9223372036854771711 cannot be represented in type 'long int' CPU: 0 PID: 17363 Comm: trinity-c0 Not tainted 4.8.0-rc1+ #88 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 0000000000000000 ffff88011457f8f0 ffffffff82344f50 0000000041b58ab3 ffffffff84f98080 ffffffff82344ea4 ffff88011457f918 ffff88011457f8c8 ffff88011457f8e0 7fffffffffffefff ffff88011457f6d8 dffffc0000000000 Call Trace: [<ffffffff82344f50>] dump_stack+0xac/0xfc [<ffffffff82344ea4>] ? _atomic_dec_and_lock+0xc4/0xc4 [<ffffffff8242f4c8>] ubsan_epilogue+0xd/0x8a [<ffffffff8242fc04>] handle_overflow+0x202/0x23d [<ffffffff8242fa02>] ? val_to_string.constprop.6+0x11e/0x11e [<ffffffff823c7837>] ? debug_smp_processor_id+0x17/0x20 [<ffffffff8131b581>] ? __sigqueue_free.part.13+0x51/0x70 [<ffffffff8146d4e0>] ? rcu_is_watching+0x110/0x110 [<ffffffff8242fc4d>] __ubsan_handle_add_overflow+0xe/0x10 [<ffffffff81476ef8>] timespec64_add_safe+0x298/0x340 [<ffffffff81476c60>] ? timespec_add_safe+0x330/0x330 [<ffffffff812f7990>] ? wait_noreap_copyout+0x1d0/0x1d0 [<ffffffff8184bf18>] poll_select_set_timeout+0xf8/0x170 [<ffffffff8184be20>] ? poll_schedule_timeout+0x2b0/0x2b0 [<ffffffff813aa9bb>] ? __might_sleep+0x5b/0x260 [<ffffffff833c8a87>] __sys_recvmmsg+0x107/0x790 [<ffffffff833c8980>] ? SyS_recvmsg+0x20/0x20 [<ffffffff81486378>] ? hrtimer_start_range_ns+0x3b8/0x1380 [<ffffffff845f8bfb>] ? _raw_spin_unlock_irqrestore+0x3b/0x60 [<ffffffff8148bcea>] ? do_setitimer+0x39a/0x8e0 [<ffffffff813aa9bb>] ? __might_sleep+0x5b/0x260 [<ffffffff833c9110>] ? __sys_recvmmsg+0x790/0x790 [<ffffffff833c91e9>] SyS_recvmmsg+0xd9/0x160 [<ffffffff833c9110>] ? __sys_recvmmsg+0x790/0x790 [<ffffffff823c7853>] ? __this_cpu_preempt_check+0x13/0x20 [<ffffffff8162f680>] ? __context_tracking_exit.part.3+0x30/0x1b0 [<ffffffff833c9110>] ? __sys_recvmmsg+0x790/0x790 [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0 [<ffffffff845f936a>] entry_SYSCALL64_slow_path+0x25/0x25 ================================================================================ Line 783 is this: 783 set_normalized_timespec64(&res, lhs.tv_sec + rhs.tv_sec, 784 lhs.tv_nsec + rhs.tv_nsec); In other words, since lhs.tv_sec and rhs.tv_sec are both time64_t, this is a signed addition which will cause undefined behaviour on overflow. Note that this is not currently a huge concern since the kernel should be built with -fno-strict-overflow by default, but could be a problem in the future, a problem with older compilers, or other compilers than gcc. The easiest way to avoid the overflow is to cast one of the arguments to unsigned (so the addition will be done using unsigned arithmetic). Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
* | timekeeping: Prints the amounts of time spent during suspendRuchi Kandoi2016-08-311-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In addition to keeping a histogram of suspend times, also print out the time spent in suspend to dmesg. This helps to keep track of suspend time while debugging using kernel logs. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com> [jstultz: Tweaked commit message] Signed-off-by: John Stultz <john.stultz@linaro.org>
* | clocksource: Defer override invalidation unless clock is unstableKyle Walker2016-08-311-3/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clocksources don't get the VALID_FOR_HRES flag until they have been checked by a watchdog. However, when using an override, the clocksource_select logic will clear the override value if the clocksource is not marked VALID_FOR_HRES during that inititial check. When using the boot arguments clocksource=<foo>, this selection can run before the watchdog, and can cause the override to be incorrectly cleared. To address this condition, the override_name is only invalidated for unstable clocksources. Otherwise, the override is left intact until after the watchdog has validated the clocksource as stable/unstable. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Kyle Walker <kwalker@redhat.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
* | hrtimer: Spelling fixesPratyush Patel2016-08-311-2/+2
|/ | | | | | | | | | | | Fix a minor spelling error. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Pratyush Patel <pratyushpatel.1995@gmail.com> [jstultz: Added commit message] Signed-off-by: John Stultz <john.stultz@linaro.org>
* timekeeping: Cap array access in timekeeping_debugJohn Stultz2016-08-241-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It was reported that hibernation could fail on the 2nd attempt, where the system hangs at hibernate() -> syscore_resume() -> i8237A_resume() -> claim_dma_lock(), because the lock has already been taken. However there is actually no other process would like to grab this lock on that problematic platform. Further investigation showed that the problem is triggered by setting /sys/power/pm_trace to 1 before the 1st hibernation. Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend, and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller than 1970) to the release date of that motherboard during POST stage, thus after resumed, it may seem that the system had a significant long sleep time which is a completely meaningless value. Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the sleep time happened to be set to 1, fls() returns 32 and we add 1 to sleep_time_bin[32], which causes an out of bounds array access and therefor memory being overwritten. As depicted by System.map: 0xffffffff81c9d080 b sleep_time_bin 0xffffffff81c9d100 B dma_spin_lock the dma_spin_lock.val is set to 1, which caused this problem. This patch adds a sanity check in tk_debug_account_sleep_time() to ensure we don't index past the sleep_time_bin array. [jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the issue slightly differently, but borrowed his excelent explanation of the issue here.] Fixes: 5c83545f24ab "power: Add option to log time spent in suspend" Reported-by: Janek Kozicki <cosurgi@gmail.com> Reported-by: Chen Yu <yu.c.chen@intel.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: linux-pm@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Xunlei Pang <xpang@redhat.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: stable <stable@vger.kernel.org> Cc: Zhang Rui <rui.zhang@intel.com> Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPINGJohn Stultz2016-08-241-1/+4
| | | | | | | | | | | | | | | | | | | | | When I added some extra sanity checking in timekeeping_get_ns() under CONFIG_DEBUG_TIMEKEEPING, I missed that the NMI safe __ktime_get_fast_ns() method was using timekeeping_get_ns(). Thus the locking added to the debug checks broke the NMI-safety of __ktime_get_fast_ns(). This patch open-codes the timekeeping_get_ns() logic for __ktime_get_fast_ns(), so can avoid any deadlocks in NMI. Fixes: 4ca22c2648f9 "timekeeping: Add warnings when overflows or underflows are observed" Reported-by: Steven Rostedt <rostedt@goodmis.org> Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: stable <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1471993702-29148-2-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* timers: Fix get_next_timer_interrupt() computationChris Metcalf2016-08-091-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The tick_nohz_stop_sched_tick() routine is not properly canceling the sched timer when nothing is pending, because get_next_timer_interrupt() is no longer returning KTIME_MAX in that case. This causes periodic interrupts when none are needed. When determining the next interrupt time, we first use __next_timer_interrupt() to get the first expiring timer in the timer wheel. If no timer is found, we return the base clock value plus NEXT_TIMER_MAX_DELTA to indicate there is no timer in the timer wheel. Back in get_next_timer_interrupt(), we set the "expires" value by converting the timer wheel expiry (in ticks) to a nsec value. But we don't want to do this if the timer wheel expiry value indicates no timer; we want to return KTIME_MAX. Prior to commit 500462a9de65 ("timers: Switch to a non-cascading wheel") we checked base->active_timers to see if any timers were active, and if not, we didn't touch the expiry value and so properly returned KTIME_MAX. Now we don't have active_timers. To fix this, we now just check the timer wheel expiry value to see if it is "now + NEXT_TIMER_MAX_DELTA", and if it is, we don't try to compute a new value based on it, but instead simply let the KTIME_MAX value in expires remain. Fixes: 500462a9de65 "timers: Switch to a non-cascading wheel" Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1470688147-22287-1-git-send-email-cmetcalf@mellanox.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds2016-07-292-58/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull smp hotplug updates from Thomas Gleixner: "This is the next part of the hotplug rework. - Convert all notifiers with a priority assigned - Convert all CPU_STARTING/DYING notifiers The final removal of the STARTING/DYING infrastructure will happen when the merge window closes. Another 700 hundred line of unpenetrable maze gone :)" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits) timers/core: Correct callback order during CPU hot plug leds/trigger/cpu: Move from CPU_STARTING to ONLINE level powerpc/numa: Convert to hotplug state machine arm/perf: Fix hotplug state machine conversion irqchip/armada: Avoid unused function warnings ARC/time: Convert to hotplug state machine clocksource/atlas7: Convert to hotplug state machine clocksource/armada-370-xp: Convert to hotplug state machine clocksource/exynos_mct: Convert to hotplug state machine clocksource/arm_global_timer: Convert to hotplug state machine rcu: Convert rcutree to hotplug state machine KVM/arm/arm64/vgic-new: Convert to hotplug state machine smp/cfd: Convert core to hotplug state machine x86/x2apic: Convert to CPU hotplug state machine profile: Convert to hotplug state machine timers/core: Convert to hotplug state machine hrtimer: Convert to hotplug state machine x86/tboot: Convert to hotplug state machine arm64/armv8 deprecated: Convert to hotplug state machine hwtracing/coresight-etm4x: Convert to hotplug state machine ...
| * timers/core: Convert to hotplug state machineRichard Cochran2016-07-151-23/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When tearing down, call timers_dead_cpu() before notify_dead(). There is a hidden dependency between: - timers - block multiqueue - rcutree If timers_dead_cpu() comes later than blk_mq_queue_reinit_notify() that latter function causes a RCU stall. Signed-off-by: Richard Cochran <rcochran@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153337.566790058@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * hrtimer: Convert to hotplug state machineThomas Gleixner2016-07-151-35/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Split out the clockevents callbacks instead of piggybacking them on hrtimers. This gets rid of a POST_DEAD user. See commit: 54e88fad223c ("sched: Make sure timers have migrated before killing the migration_thread") We just move the callback state to the proper place in the state machine. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153337.485419196@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2016-07-2512-526/+741
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "This update provides the following changes: - The rework of the timer wheel which addresses the shortcomings of the current wheel (cascading, slow search for next expiring timer, etc). That's the first major change of the wheel in almost 20 years since Finn implemted it. - A large overhaul of the clocksource drivers init functions to consolidate the Device Tree initialization - Some more Y2038 updates - A capability fix for timerfd - Yet another clock chip driver - The usual pile of updates, comment improvements all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (130 commits) tick/nohz: Optimize nohz idle enter clockevents: Make clockevents_subsys static clocksource/drivers/time-armada-370-xp: Fix return value check timers: Implement optimization for same expiry time in mod_timer() timers: Split out index calculation timers: Only wake softirq if necessary timers: Forward the wheel clock whenever possible timers/nohz: Remove pointless tick_nohz_kick_tick() function timers: Optimize collect_expired_timers() for NOHZ timers: Move __run_timers() function timers: Remove set_timer_slack() leftovers timers: Switch to a non-cascading wheel timers: Reduce the CPU index space to 256k timers: Give a few structs and members proper names hlist: Add hlist_is_singular_node() helper signals: Use hrtimer for sigtimedwait() timers: Remove the deprecated mod_timer_pinned() API timers, net/ipv4/inet: Initialize connection request timers as pinned timers, drivers/tty/mips_ejtag: Initialize the poll timer as pinned timers, drivers/tty/metag_da: Initialize the poll timer as pinned ...
| * | tick/nohz: Optimize nohz idle enterGaurav Jindal2016-07-191-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tick_nohz_start_idle is called before checking whether the idle tick can be stopped. If the tick cannot be stopped, calling tick_nohz_start_idle() is pointless and just wasting CPU cycles. Only invoke tick_nohz_start_idle() when can_stop_idle_tick() returns true. A short one minute observation of the effect on ARM64 shows a reduction of calls by 1.5% thus optimizing the idle entry sequence. [tglx: Massaged changelog ] Co-developed-by: Sanjeev Yadav<sanjeev.yadav@spreadtrum.com> Signed-off-by: Gaurav Jindal<gaurav.jindal@spreadtrum.com> Link: http://lkml.kernel.org/r/20160714120416.GB21099@gaurav.jindal@spreadtrum.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | clockevents: Make clockevents_subsys staticBen Dooks2016-07-191-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | The clockevents_subsys struct is used for sysfs support and is not declared or used outside the file it is defined in. Fix the following warning by making it static: kernel/time/clockevents.c:648:17: warning: symbol 'clockevents_subsys' was not declared. Should it be static? Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Cc: linux-kernel@lists.codethink.co.uk Link: http://lkml.kernel.org/r/1466178974-7105-1-git-send-email-ben.dooks@codethink.co.uk Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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