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2014-12-19Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull NOHZ update from Thomas Gleixner: "Remove the call into the nohz idle code from the fake 'idle' thread in the powerclamp driver along with the export of those functions which was smuggeled in via the thermal tree. People have tried to hack around it in the nohz core code, but it just violates all rightful assumptions of that code about the only valid calling context (i.e. the proper idle task). The powerclamp trainwreck will still work, it just wont get the benefit of long idle sleeps" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick/powerclamp: Remove tick_nohz_idle abuse
2014-12-19tick/powerclamp: Remove tick_nohz_idle abuseThomas Gleixner
commit 4dbd27711cd9 "tick: export nohz tick idle symbols for module use" was merged via the thermal tree without an explicit ack from the relevant maintainers. The exports are abused by the intel powerclamp driver which implements a fake idle state from a sched FIFO task. This causes all kinds of wreckage in the NOHZ core code which rightfully assumes that tick_nohz_idle_enter/exit() are only called from the idle task itself. Recent changes in the NOHZ core lead to a failure of the powerclamp driver and now people try to hack completely broken and backwards workarounds into the NOHZ core code. This is completely unacceptable and just papers over the real problem. There are way more subtle issues lurking around the corner. The real solution is to fix the powerclamp driver by rewriting it with a sane concept, but that's beyond the scope of this. So the only solution for now is to remove the calls into the core NOHZ code from the powerclamp trainwreck along with the exports. Fixes: d6d71ee4a14a "PM: Introduce Intel PowerClamp Driver" Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Pan Jacob jun <jacob.jun.pan@intel.com> Cc: LKP <lkp@01.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Zhang Rui <rui.zhang@intel.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1412181110110.17382@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-12-15Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linuxLinus Torvalds
Pull drm updates from Dave Airlie: "Highlights: - AMD KFD driver merge This is the AMD HSA interface for exposing a lowlevel interface for GPGPU use. They have an open source userspace built on top of this interface, and the code looks as good as it was going to get out of tree. - Initial atomic modesetting work The need for an atomic modesetting interface to allow userspace to try and send a complete set of modesetting state to the driver has arisen, and been suffering from neglect this past year. No more, the start of the common code and changes for msm driver to use it are in this tree. Ongoing work to get the userspace ioctl finished and the code clean will probably wait until next kernel. - DisplayID 1.3 and tiled monitor exposed to userspace. Tiled monitor property is now exposed for userspace to make use of. - Rockchip drm driver merged. - imx gpu driver moved out of staging Other stuff: - core: panel - MIPI DSI + new panels. expose suggested x/y properties for virtual GPUs - i915: Initial Skylake (SKL) support gen3/4 reset work start of dri1/ums removal infoframe tracking fixes for lots of things. - nouveau: tegra k1 voltage support GM204 modesetting support GT21x memory reclocking work - radeon: CI dpm fixes GPUVM improvements Initial DPM fan control - rcar-du: HDMI support added removed some support for old boards slave encoder driver for Analog Devices adv7511 - exynos: Exynos4415 SoC support - msm: a4xx gpu support atomic helper conversion - tegra: iommu support universal plane support ganged-mode DSI support - sti: HDMI i2c improvements - vmwgfx: some late fixes. - qxl: use suggested x/y properties" * 'drm-next' of git://people.freedesktop.org/~airlied/linux: (969 commits) drm: sti: fix module compilation issue drm/i915: save/restore GMBUS freq across suspend/resume on gen4 drm: sti: correctly cleanup CRTC and planes drm: sti: add HQVDP plane drm: sti: add cursor plane drm: sti: enable auxiliary CRTC drm: sti: fix delay in VTG programming drm: sti: prepare sti_tvout to support auxiliary crtc drm: sti: use drm_crtc_vblank_{on/off} instead of drm_vblank_{on/off} drm: sti: fix hdmi avi infoframe drm: sti: remove event lock while disabling vblank drm: sti: simplify gdp code drm: sti: clear all mixer control drm: sti: remove gpio for HDMI hot plug detection drm: sti: allow to change hdmi ddc i2c adapter drm/doc: Document drm_add_modes_noedid() usage drm/i915: Remove '& 0xffff' from the mask given to WA_REG() drm/i915: Invert the mask and val arguments in wa_add() and WA_REG() drm: Zero out DRM object memory upon cleanup drm/i915/bdw: Fix the write setting up the WIZ hashing mode ...
2014-12-12Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree update from Jiri Kosina: "Usual stuff: documentation updates, printk() fixes, etc" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (24 commits) intel_ips: fix a type in error message cpufreq: cpufreq-dt: Move newline to end of error message ps3rom: fix error return code treewide: fix typo in printk and Kconfig ARM: dts: bcm63138: change "interupts" to "interrupts" Replace mentions of "list_struct" to "list_head" kernel: trace: fix printk message scsi: mpt2sas: fix ioctl in comment zbud, zswap: change module author email clocksource: Fix 'clcoksource' typo in comment arm: fix wording of "Crotex" in CONFIG_ARCH_EXYNOS3 help gpio: msm-v1: make boolean argument more obvious usb: Fix typo in usb-serial-simple.c PCI: Fix comment typo 'COMFIG_PM_OPS' powerpc: Fix comment typo 'CONIFG_8xx' powerpc: Fix comment typos 'CONFiG_ALTIVEC' clk: st: Spelling s/stucture/structure/ isci: Spelling s/stucture/structure/ usb: gadget: zero: Spelling s/infrastucture/infrastructure/ treewide: Fix company name in module descriptions ...
2014-12-11Merge branch 'for-3.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu Pull percpu updates from Tejun Heo: "Nothing interesting. A patch to convert the remaining __get_cpu_var() users, another to fix non-critical off-by-one in an assertion and a cosmetic conversion to lockless_dereference() in percpu-ref. The back-merge from mainline is to receive lockless_dereference()" * 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: Replace smp_read_barrier_depends() with lockless_dereference() percpu: Convert remaining __get_cpu_var uses in 3.18-rcX percpu: off by one in BUG_ON()
2014-12-10Merge branch 'timers-2038-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more 2038 timer work from Thomas Gleixner: "Two more patches for the ongoing 2038 work: - New accessors to clock MONOTONIC and REALTIME seconds This is a seperate branch as Arnd has follow up work depending on this" * 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Provide y2038 safe accessor to the seconds portion of CLOCK_REALTIME timekeeping: Provide fast accessor to the seconds part of CLOCK_MONOTONIC
2014-12-10Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer core updates from Thomas Gleixner: "The time(r) departement provides: - more infrastructure work on the year 2038 issue - a few fixes in the Armada SoC timers - the usual pile of fixlets and improvements" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: armada-370-xp: Use the reference clock on A375 SoC watchdog: orion: Use the reference clock on Armada 375 SoC clocksource: armada-370-xp: Add missing clock enable time: Fix sign bug in NTP mult overflow warning time: Remove timekeeping_inject_sleeptime() rtc: Update suspend/resume timing to use 64bit time rtc/lib: Provide y2038 safe rtc_tm_to_time()/rtc_time_to_tm() replacement time: Fixup comments to reflect usage of timespec64 time: Expose get_monotonic_coarse64() for in-kernel uses time: Expose getrawmonotonic64 for in-kernel uses time: Provide y2038 safe mktime() replacement time: Provide y2038 safe timekeeping_inject_sleeptime() replacement time: Provide y2038 safe do_settimeofday() replacement time: Complete NTP adjustment threshold judging conditions time: Avoid possible NTP adjustment mult overflow. time: Rename udelay_test.c to test_udelay.c clocksource: sirf: Remove hard-coded clock rate
2014-12-09Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "These are the main changes in this cycle: - Streamline RCU's use of per-CPU variables, shifting from "cpu" arguments to functions to "this_"-style per-CPU variable accessors. - signal-handling RCU updates. - real-time updates. - torture-test updates. - miscellaneous fixes. - documentation updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits) rcu: Fix FIXME in rcu_tasks_kthread() rcu: More info about potential deadlocks with rcu_read_unlock() rcu: Optimize cond_resched_rcu_qs() rcu: Add sparse check for RCU_INIT_POINTER() documentation: memory-barriers.txt: Correct example for reorderings documentation: Add atomic_long_t to atomic_ops.txt documentation: Additional restriction for control dependencies documentation: Document RCU self test boot params rcutorture: Fix rcu_torture_cbflood() memory leak rcutorture: Remove obsolete kversion param in kvm.sh rcutorture: Remove stale test configurations rcutorture: Enable RCU self test in configs rcutorture: Add early boot self tests torture: Run Linux-kernel binary out of results directory cpu: Avoid puts_pending overflow rcu: Remove "cpu" argument to rcu_cleanup_after_idle() rcu: Remove "cpu" argument to rcu_prepare_for_idle() rcu: Remove "cpu" argument to rcu_needs_cpu() rcu: Remove "cpu" argument to rcu_note_context_switch() rcu: Remove "cpu" argument to rcu_preempt_check_callbacks() ...
2014-12-05drm/i915: compute wait_ioctl timeout correctlyDaniel Vetter
We've lost the +1 required for correct timeouts in commit 5ed0bdf21a85d78e04f89f15ccf227562177cbd9 Author: Thomas Gleixner <tglx@linutronix.de> Date: Wed Jul 16 21:05:06 2014 +0000 drm: i915: Use nsec based interfaces Use ktime_get_raw_ns() and get rid of the back and forth timespec conversions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: John Stultz <john.stultz@linaro.org> So fix this up by reinstating our handrolled _timeout function. While at it bother with handling MAX_JIFFIES. v2: Convert to usecs (we don't care about the accuracy anyway) first to avoid overflow issues Dave Gordon spotted. v3: Drop the explicit MAX_JIFFY_OFFSET check, usecs_to_jiffies should take care of that already. It might be a bit too enthusiastic about it though. v4: Chris has a much nicer color, so use his implementation. This requires to export nsec_to_jiffies from time.c. Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dave Gordon <david.s.gordon@intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82749 Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Acked-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2014-11-25time: Fix sign bug in NTP mult overflow warningJohn Stultz
In commit 6067dc5a8c2b ("time: Avoid possible NTP adjustment mult overflow") a new check was added to watch for adjustments that could cause a mult overflow. Unfortunately the check compares a signed with unsigned value and ignored the case where the adjustment was negative, which causes spurious warn-ons on some systems (and seems like it would result in problematic time adjustments there as well, due to the early return). Thus this patch adds a check to make sure the adjustment is positive before we check for an overflow, and resovles the issue in my testing. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Debugged-by: pang.xunlei <pang.xunlei@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1416890145-30048-1-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-11-22Merge branch 'master' into for-3.19Tejun Heo
Pull in to receive 54ef6df3f3f1 ("rcu: Provide counterpart to rcu_dereference() for non-RCU situations"). Signed-off-by: Tejun Heo <tj@kernel.org>
2014-11-21time: Fixup comments to reflect usage of timespec64John Stultz
Fix up a few comments that weren't updated when the functions were converted to use timespec64 structures. Acked-by: Arnd Bergmann <arnd.bergmann@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Expose get_monotonic_coarse64() for in-kernel usesJohn Stultz
Adds a timespec64 based get_monotonic_coarse64() implementation that can be used as we convert internal users of get_monotonic_coarse away from using timespecs. Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Expose getrawmonotonic64 for in-kernel usesJohn Stultz
Adds a timespec64 based getrawmonotonic64() implementation that can be used as we convert internal users of getrawmonotonic away from using timespecs. Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Provide y2038 safe mktime() replacementpang.xunlei
As part of addressing "y2038 problem" for in-kernel uses, this patch adds safe mktime64() using time64_t. After this patch, mktime() is deprecated and all its call sites will be fixed using mktime64(), after that it can be removed. Signed-off-by: pang.xunlei <pang.xunlei@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Provide y2038 safe timekeeping_inject_sleeptime() replacementpang.xunlei
As part of addressing "y2038 problem" for in-kernel uses, this patch adds timekeeping_inject_sleeptime64() using timespec64. After this patch, timekeeping_inject_sleeptime() is deprecated and all its call sites will be fixed using the new interface, after that it can be removed. NOTE: timekeeping_inject_sleeptime() is safe actually, but we want to eliminate timespec eventually, so comes this patch. Signed-off-by: pang.xunlei <pang.xunlei@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Provide y2038 safe do_settimeofday() replacementpang.xunlei
The kernel uses 32-bit signed value(time_t) for seconds elapsed 1970-01-01:00:00:00, thus it will overflow at 2038-01-19 03:14:08 on 32-bit systems. This is widely known as the y2038 problem. As part of addressing "y2038 problem" for in-kernel uses, this patch adds safe do_settimeofday64() using timespec64. After this patch, do_settimeofday() is deprecated and all its call sites will be fixed using do_settimeofday64(), after that it can be removed. Signed-off-by: pang.xunlei <pang.xunlei@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Complete NTP adjustment threshold judging conditionspang.xunlei
The clocksource mult-adjustment threshold is [mult-maxadj, mult+maxadj], timekeeping_adjust() only deals with the upper threshold, but misses the lower threshold. This patch adds the lower threshold judging condition. Signed-off-by: pang.xunlei <pang.xunlei@linaro.org> [jstultz: Minor fix for > 80 char line] Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Avoid possible NTP adjustment mult overflow.pang.xunlei
Ideally, __clocksource_updatefreq_scale, selects the largest shift value possible for a clocksource. This results in the mult memember of struct clocksource being particularly large, although not so large that NTP would adjust the clock to cause it to overflow. That said, nothing actually prohibits an overflow from occuring, its just that it "shouldn't" occur. So while very unlikely, and so far never observed, the value of (cs->mult+cs->maxadj) may have a chance to reach very near 0xFFFFFFFF, so there is a possibility it may overflow when doing NTP positive adjustment See the following detail: When NTP slewes the clock, kernel goes through update_wall_time()->...->timekeeping_apply_adjustment(): tk->tkr.mult += mult_adj; Since there is no guard against it, its possible tk->tkr.mult may overflow during this operation. This patch avoids any possible mult overflow by judging the overflow case before adding mult_adj to mult, also adds the WARNING message when capturing such case. Signed-off-by: pang.xunlei <pang.xunlei@linaro.org> [jstultz: Reworded commit message] Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-21time: Rename udelay_test.c to test_udelay.cJohn Stultz
Kees requested that this test module be renamed for consistency sake, so this patch renames the udelay_test.c file (recently added to tip/timers/core for 3.17) to test_udelay.c Cc: Kees Cook <keescook@chromium.org> Cc: Greg KH <greg@kroah.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Linux-Next <linux-next@vger.kernel.org> Cc: David Riley <davidriley@chromium.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-11-20Merge Linus' tree to be be to apply submitted patches to newer code thanJiri Kosina
current trivial.git base
2014-11-20Merge branch 'rcu/next' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Streamline RCU's use of per-CPU variables, shifting from "cpu" arguments to functions to "this_"-style per-CPU variable accessors. - Signal-handling RCU updates. - Real-time updates. - Torture-test updates. - Miscellaneous fixes. - Documentation updates. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-11-16sched/cputime: Fix cpu_timer_sample_group() double accountingPeter Zijlstra
While looking over the cpu-timer code I found that we appear to add the delta for the calling task twice, through: cpu_timer_sample_group() thread_group_cputimer() thread_group_cputime() times->sum_exec_runtime += task_sched_runtime(); *sample = cputime.sum_exec_runtime + task_delta_exec(); Which would make the sample run ahead, making the sleep short. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rik van Riel <riel@redhat.com> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20141112113737.GI10476@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-11-03rcu: Remove "cpu" argument to rcu_needs_cpu()Paul E. McKenney
The "cpu" argument to rcu_needs_cpu() is always the current CPU, so drop it. This in turn allows the "cpu" argument to rcu_cpu_has_callbacks() to be removed, which allows the uses of "cpu" in both functions to be replaced with a this_cpu_ptr(). Again, the anticipated cross-CPU uses of these functions has been replaced by NO_HZ_FULL. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
2014-11-03rcu: Remove "cpu" argument to rcu_check_callbacks()Paul E. McKenney
The "cpu" argument was kept around on the off-chance that RCU might offload scheduler-clock interrupts. However, this offload approach has been replaced by NO_HZ_FULL, which offloads -all- RCU processing from qualifying CPUs. It is therefore time to remove the "cpu" argument to rcu_check_callbacks(), which this commit does. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
2014-10-29percpu: Convert remaining __get_cpu_var uses in 3.18-rcXChristoph Lameter
During the 3.18 merge period additional __get_cpu_var uses were added. The patch converts these to this_cpu_ptr(). Signed-off-by: Christoph Lameter <cl@linux.com> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-10-29timekeeping: Provide y2038 safe accessor to the seconds portion of ↵Heena Sirwani
CLOCK_REALTIME ktime_get_real_seconds() is the replacement function for get_seconds() returning the seconds portion of CLOCK_REALTIME in a time64_t. For 64bit the function is equivivalent to get_seconds(), but for 32bit it protects the readout with the timekeeper sequence count. This is required because 32-bit machines cannot access 64-bit tk->xtime_sec variable atomically. [tglx: Massaged changelog and added docbook comment ] Signed-off-by: Heena Sirwani <heenasirwani@gmail.com> Reviewed-by: Arnd Bergman <arnd@arndb.de> Cc: John Stultz <john.stultz@linaro.org> Cc: opw-kernel@googlegroups.com Link: http://lkml.kernel.org/r/7adcfaa8962b8ad58785d9a2456c3f77d93c0ffb.1414578445.git.heenasirwani@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-29timekeeping: Provide fast accessor to the seconds part of CLOCK_MONOTONICHeena Sirwani
This is the counterpart to get_seconds() based on CLOCK_MONOTONIC. The use case for this interface are kernel internal coarse grained timestamps which do neither require the nanoseconds fraction of current time nor the CLOCK_REALTIME properties. Such timestamps can currently only retrieved by calling ktime_get_ts64() and using the tv_sec field of the returned timespec64. That's inefficient as it involves the read of the clocksource, math operations and must be protected by the timekeeper sequence counter. To avoid the sequence counter protection we restrict the return value to unsigned 32bit on 32bit machines. This covers ~136 years of uptime and therefor an overflow is not expected to hit anytime soon. To avoid math in the function we calculate the current seconds portion of CLOCK_MONOTONIC when the timekeeper gets updated in tk_update_ktime_data() similar to the CLOCK_REALTIME counterpart xtime_sec. [ tglx: Massaged changelog, simplified and commented the update function, added docbook comment ] Signed-off-by: Heena Sirwani <heenasirwani@gmail.com> Reviewed-by: Arnd Bergman <arnd@arndb.de> Cc: John Stultz <john.stultz@linaro.org> Cc: opw-kernel@googlegroups.com Link: http://lkml.kernel.org/r/da0b63f4bdf3478909f92becb35861197da3a905.1414578445.git.heenasirwani@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-29clocksource: Fix 'clcoksource' typo in commentJames Hartley
Simple typo in a comment, so fix it. Signed-off-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-10-25clockevents: Prevent shift out of boundsThomas Gleixner
Andrey reported that on a kernel with UBSan enabled he found: UBSan: Undefined behaviour in ../kernel/time/clockevents.c:75:34 I guess it should be 1ULL here instead of 1U: (!ismax || evt->mult <= (1U << evt->shift))) That's indeed the correct solution because shift might be 32. Reported-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-25posix-timers: Fix stack info leak in timer_create()Mathias Krause
If userland creates a timer without specifying a sigevent info, we'll create one ourself, using a stack local variable. Particularly will we use the timer ID as sival_int. But as sigev_value is a union containing a pointer and an int, that assignment will only partially initialize sigev_value on systems where the size of a pointer is bigger than the size of an int. On such systems we'll copy the uninitialized stack bytes from the timer_create() call to userland when the timer actually fires and we're going to deliver the signal. Initialize sigev_value with 0 to plug the stack info leak. Found in the PaX patch, written by the PaX Team. Fixes: 5a9fa7307285 ("posix-timers: kill ->it_sigev_signo and...") Signed-off-by: Mathias Krause <minipli@googlemail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Brad Spengler <spender@grsecurity.net> Cc: PaX Team <pageexec@freemail.hu> Cc: <stable@vger.kernel.org> # v2.6.28+ Link: http://lkml.kernel.org/r/1412456799-32339-1-git-send-email-minipli@googlemail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-15Merge branch 'for-3.18-consistent-ops' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu Pull percpu consistent-ops changes from Tejun Heo: "Way back, before the current percpu allocator was implemented, static and dynamic percpu memory areas were allocated and handled separately and had their own accessors. The distinction has been gone for many years now; however, the now duplicate two sets of accessors remained with the pointer based ones - this_cpu_*() - evolving various other operations over time. During the process, we also accumulated other inconsistent operations. This pull request contains Christoph's patches to clean up the duplicate accessor situation. __get_cpu_var() uses are replaced with with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr(). Unfortunately, the former sometimes is tricky thanks to C being a bit messy with the distinction between lvalues and pointers, which led to a rather ugly solution for cpumask_var_t involving the introduction of this_cpu_cpumask_var_ptr(). This converts most of the uses but not all. Christoph will follow up with the remaining conversions in this merge window and hopefully remove the obsolete accessors" * 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits) irqchip: Properly fetch the per cpu offset percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write. percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t Revert "powerpc: Replace __get_cpu_var uses" percpu: Remove __this_cpu_ptr clocksource: Replace __this_cpu_ptr with raw_cpu_ptr sparc: Replace __get_cpu_var uses avr32: Replace __get_cpu_var with __this_cpu_write blackfin: Replace __get_cpu_var uses tile: Use this_cpu_ptr() for hardware counters tile: Replace __get_cpu_var uses powerpc: Replace __get_cpu_var uses alpha: Replace __get_cpu_var ia64: Replace __get_cpu_var uses s390: cio driver &__get_cpu_var replacements s390: Replace __get_cpu_var uses mips: Replace __get_cpu_var uses MIPS: Replace __get_cpu_var uses in FPU emulator. arm: Replace __this_cpu_ptr with raw_cpu_ptr ...
2014-10-14Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Martin Schwidefsky: "This patch set contains the main portion of the changes for 3.18 in regard to the s390 architecture. It is a bit bigger than usual, mainly because of a new driver and the vector extension patches. The interesting bits are: - Quite a bit of work on the tracing front. Uprobes is enabled and the ftrace code is reworked to get some of the lost performance back if CONFIG_FTRACE is enabled. - To improve boot time with CONFIG_DEBIG_PAGEALLOC, support for the IPTE range facility is added. - The rwlock code is re-factored to improve writer fairness and to be able to use the interlocked-access instructions. - The kernel part for the support of the vector extension is added. - The device driver to access the CD/DVD on the HMC is added, this will hopefully come in handy to improve the installation process. - Add support for control-unit initiated reconfiguration. - The crypto device driver is enhanced to enable the additional AP domains and to allow the new crypto hardware to be used. - Bug fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (39 commits) s390/ftrace: simplify enabling/disabling of ftrace_graph_caller s390/ftrace: remove 31 bit ftrace support s390/kdump: add support for vector extension s390/disassembler: add vector instructions s390: add support for vector extension s390/zcrypt: Toleration of new crypto hardware s390/idle: consolidate idle functions and definitions s390/nohz: use a per-cpu flag for arch_needs_cpu s390/vtime: do not reset idle data on CPU hotplug s390/dasd: add support for control unit initiated reconfiguration s390/dasd: fix infinite loop during format s390/mm: make use of ipte range facility s390/setup: correct 4-level kernel page table detection s390/topology: call set_sched_topology early s390/uprobes: architecture backend for uprobes s390/uprobes: common library for kprobes and uprobes s390/rwlock: use the interlocked-access facility 1 instructions s390/rwlock: improve writer fairness s390/rwlock: remove interrupt-enabling rwlock variant. s390/mm: remove change bit override support ...
2014-10-13Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes in this cycle were: - Optimized support for Intel "Cluster-on-Die" (CoD) topologies (Dave Hansen) - Various sched/idle refinements for better idle handling (Nicolas Pitre, Daniel Lezcano, Chuansheng Liu, Vincent Guittot) - sched/numa updates and optimizations (Rik van Riel) - sysbench speedup (Vincent Guittot) - capacity calculation cleanups/refactoring (Vincent Guittot) - Various cleanups to thread group iteration (Oleg Nesterov) - Double-rq-lock removal optimization and various refactorings (Kirill Tkhai) - various sched/deadline fixes ... and lots of other changes" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits) sched/dl: Use dl_bw_of() under rcu_read_lock_sched() sched/fair: Delete resched_cpu() from idle_balance() sched, time: Fix build error with 64 bit cputime_t on 32 bit systems sched: Improve sysbench performance by fixing spurious active migration sched/x86: Fix up typo in topology detection x86, sched: Add new topology for multi-NUMA-node CPUs sched/rt: Use resched_curr() in task_tick_rt() sched: Use rq->rd in sched_setaffinity() under RCU read lock sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask' sched: Use dl_bw_of() under RCU read lock sched/fair: Remove duplicate code from can_migrate_task() sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW sched: print_rq(): Don't use tasklist_lock sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock() sched: Fix the task-group check in tg_has_rt_tasks() sched/fair: Leverage the idle state info when choosing the "idlest" cpu sched: Let the scheduler see CPU idle states sched/deadline: Fix inter- exclusive cpusets migrations sched/deadline: Clear dl_entity params when setscheduling to different class sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault() ...
2014-10-09Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "Nothing really exciting this time: - a few fixlets in the NOHZ code - a new ARM SoC timer abomination. One should expect that we have enough of them already, but they insist on inventing new ones. - the usual bunch of ARM SoC timer updates. That feels like herding cats" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: arm_arch_timer: Consolidate arch_timer_evtstrm_enable clocksource: arm_arch_timer: Enable counter access for 32-bit ARM clocksource: arm_arch_timer: Change clocksource name if CP15 unavailable clocksource: sirf: Disable counter before re-setting it clocksource: cadence_ttc: Add support for 32bit mode clocksource: tcb_clksrc: Sanitize IRQ request clocksource: arm_arch_timer: Discard unavailable timers correctly clocksource: vf_pit_timer: Support shutdown mode ARM: meson6: clocksource: Add Meson6 timer support ARM: meson: documentation: Add timer documentation clocksource: sh_tmu: Document r8a7779 binding clocksource: sh_mtu2: Document r7s72100 binding clocksource: sh_cmt: Document SoC specific bindings timerfd: Remove an always true check nohz: Avoid tick's double reprogramming in highres mode nohz: Fix spurious periodic tick behaviour in low-res dynticks mode
2014-10-09Merge branch 'timers-nohz-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Ingo Molnar: "Main changes: - Fix the deadlock reported by Dave Jones et al - Clean up and fix nohz_full interaction with arch abilities - nohz init code consolidation/cleanup" * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: nohz: nohz full depends on irq work self IPI support nohz: Consolidate nohz full init code arm64: Tell irq work about self IPI support arm: Tell irq work about self IPI support x86: Tell irq work about self IPI support irq_work: Force raised irq work to run on irq work interrupt irq_work: Introduce arch_irq_work_has_interrupt() nohz: Move nohz full init call to tick init
2014-10-09s390/nohz: use a per-cpu flag for arch_needs_cpuMartin Schwidefsky
Move the nohz_delay bit from the s390_idle data structure to the per-cpu flags. Clear the nohz delay flag in __cpu_disable and remove the cpu hotplug notifier that used to do this. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-09-19sched, cleanup, treewide: Remove set_current_state(TASK_RUNNING) after ↵Kirill Tkhai
schedule() schedule(), io_schedule() and schedule_timeout() always return with TASK_RUNNING state set, so one more setting is unnecessary. (All places in patch are visible good, only exception is kiblnd_scheduler() from: drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c Its schedule() is one line above standard 3 lines of unified diff) No places where set_current_state() is used for mb(). Signed-off-by: Kirill Tkhai <ktkhai@parallels.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/1410529254.3569.23.camel@tkhai Cc: Alasdair Kergon <agk@redhat.com> Cc: Anil Belur <askb23@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: David Airlie <airlied@linux.ie> Cc: David Howells <dhowells@redhat.com> Cc: Dmitry Eremin <dmitry.eremin@intel.com> Cc: Frank Blaschka <blaschka@linux.vnet.ibm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Isaac Huang <he.huang@intel.com> Cc: James E.J. Bottomley <JBottomley@parallels.com> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: J. Bruce Fields <bfields@fieldses.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Liang Zhen <liang.zhen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Masaru Nomura <massa.nomura@gmail.com> Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: Oleg Drokin <green@linuxhacker.ru> Cc: Peng Tao <bergwolf@gmail.com> Cc: Richard Weinberger <richard@nod.at> Cc: Robert Love <robert.w.love@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Trond Myklebust <trond.myklebust@primarydata.com> Cc: Ursula Braun <ursula.braun@de.ibm.com> Cc: Zi Shen Lim <zlim.lnx@gmail.com> Cc: devel@driverdev.osuosl.org Cc: dm-devel@redhat.com Cc: dri-devel@lists.freedesktop.org Cc: fcoe-devel@open-fcoe.org Cc: jfs-discussion@lists.sourceforge.net Cc: linux390@de.ibm.com Cc: linux-afs@lists.infradead.org Cc: linux-cris-kernel@axis.com Cc: linux-kernel@vger.kernel.org Cc: linux-nfs@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linux-raid@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: qla2xxx-upstream@qlogic.com Cc: user-mode-linux-devel@lists.sourceforge.net Cc: user-mode-linux-user@lists.sourceforge.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-13nohz: nohz full depends on irq work self IPI supportFrederic Weisbecker
The nohz full functionality depends on IRQ work to trigger its own interrupts. As it's used to restart the tick, we can't rely on the tick fallback for irq work callbacks, ie: we can't use the tick to restart the tick itself. Lets reject the full dynticks initialization if that arch support isn't available. As a side effect, this makes sure that nohz kick is never called from the tick. That otherwise would result in illegal hrtimer self-cancellation and lockup. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-09-13nohz: Consolidate nohz full init codeFrederic Weisbecker
The supports for CONFIG_NO_HZ_FULL_ALL=y and the nohz_full= kernel parameter both have their own way to do the same thing: allocate full dynticks cpumasks, fill them and initialize some state variables. Lets consolidate that all in the same place. While at it, convert some regular printk message to warnings when fundamental allocations fail. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-09-13irq_work: Force raised irq work to run on irq work interruptFrederic Weisbecker
The nohz full kick, which restarts the tick when any resource depend on it, can't be executed anywhere given the operation it does on timers. If it is called from the scheduler or timers code, chances are that we run into a deadlock. This is why we run the nohz full kick from an irq work. That way we make sure that the kick runs on a virgin context. However if that's the case when irq work runs in its own dedicated self-ipi, things are different for the big bunch of archs that don't support the self triggered way. In order to support them, irq works are also handled by the timer interrupt as fallback. Now when irq works run on the timer interrupt, the context isn't blank. More precisely, they can run in the context of the hrtimer that runs the tick. But the nohz kick cancels and restarts this hrtimer and cancelling an hrtimer from itself isn't allowed. This is why we run in an endless loop: Kernel panic - not syncing: Watchdog detected hard LOCKUP on cpu 2 CPU: 2 PID: 7538 Comm: kworker/u8:8 Not tainted 3.16.0+ #34 Workqueue: btrfs-endio-write normal_work_helper [btrfs] ffff880244c06c88 000000001b486fe1 ffff880244c06bf0 ffffffff8a7f1e37 ffffffff8ac52a18 ffff880244c06c78 ffffffff8a7ef928 0000000000000010 ffff880244c06c88 ffff880244c06c20 000000001b486fe1 0000000000000000 Call Trace: <NMI[<ffffffff8a7f1e37>] dump_stack+0x4e/0x7a [<ffffffff8a7ef928>] panic+0xd4/0x207 [<ffffffff8a1450e8>] watchdog_overflow_callback+0x118/0x120 [<ffffffff8a186b0e>] __perf_event_overflow+0xae/0x350 [<ffffffff8a184f80>] ? perf_event_task_disable+0xa0/0xa0 [<ffffffff8a01a4cf>] ? x86_perf_event_set_period+0xbf/0x150 [<ffffffff8a187934>] perf_event_overflow+0x14/0x20 [<ffffffff8a020386>] intel_pmu_handle_irq+0x206/0x410 [<ffffffff8a01937b>] perf_event_nmi_handler+0x2b/0x50 [<ffffffff8a007b72>] nmi_handle+0xd2/0x390 [<ffffffff8a007aa5>] ? nmi_handle+0x5/0x390 [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 [<ffffffff8a008062>] default_do_nmi+0x72/0x1c0 [<ffffffff8a008268>] do_nmi+0xb8/0x100 [<ffffffff8a7ff66a>] end_repeat_nmi+0x1e/0x2e [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 <<EOE><IRQ[<ffffffff8a0ccd2f>] lock_acquired+0xaf/0x450 [<ffffffff8a0f74c5>] ? lock_hrtimer_base.isra.20+0x25/0x50 [<ffffffff8a7fc678>] _raw_spin_lock_irqsave+0x78/0x90 [<ffffffff8a0f74c5>] ? lock_hrtimer_base.isra.20+0x25/0x50 [<ffffffff8a0f74c5>] lock_hrtimer_base.isra.20+0x25/0x50 [<ffffffff8a0f7723>] hrtimer_try_to_cancel+0x33/0x1e0 [<ffffffff8a0f78ea>] hrtimer_cancel+0x1a/0x30 [<ffffffff8a109237>] tick_nohz_restart+0x17/0x90 [<ffffffff8a10a213>] __tick_nohz_full_check+0xc3/0x100 [<ffffffff8a10a25e>] nohz_full_kick_work_func+0xe/0x10 [<ffffffff8a17c884>] irq_work_run_list+0x44/0x70 [<ffffffff8a17c8da>] irq_work_run+0x2a/0x50 [<ffffffff8a0f700b>] update_process_times+0x5b/0x70 [<ffffffff8a109005>] tick_sched_handle.isra.21+0x25/0x60 [<ffffffff8a109b81>] tick_sched_timer+0x41/0x60 [<ffffffff8a0f7aa2>] __run_hrtimer+0x72/0x470 [<ffffffff8a109b40>] ? tick_sched_do_timer+0xb0/0xb0 [<ffffffff8a0f8707>] hrtimer_interrupt+0x117/0x270 [<ffffffff8a034357>] local_apic_timer_interrupt+0x37/0x60 [<ffffffff8a80010f>] smp_apic_timer_interrupt+0x3f/0x50 [<ffffffff8a7fe52f>] apic_timer_interrupt+0x6f/0x80 To fix this we force non-lazy irq works to run on irq work self-IPIs when available. That ability of the arch to trigger irq work self IPIs is available with arch_irq_work_has_interrupt(). Reported-by: Catalin Iacob <iacobcatalin@gmail.com> Reported-by: Dave Jones <davej@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-09-13nohz: Move nohz full init call to tick initFrederic Weisbecker
This way we unbloat a bit main.c and more importantly we initialize nohz full after init_IRQ(). This dependency will be needed in further patches because nohz full needs irq work to raise its own IRQ. Information about the support for this ability on ARM64 is obtained on init_IRQ() which initialize the pointer to __smp_call_function. Since tick_init() is called right after init_IRQ(), this is a good place to call tick_nohz_init() and prepare for that dependency. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-09-12alarmtimer: Lock k_itimer during timer callbackRichard Larocque
Locks the k_itimer's it_lock member when handling the alarm timer's expiry callback. The regular posix timers defined in posix-timers.c have this lock held during timout processing because their callbacks are routed through posix_timer_fn(). The alarm timers follow a different path, so they ought to grab the lock somewhere else. Cc: stable@vger.kernel.org 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: Sharvil Nanavati <sharvil@google.com> Signed-off-by: Richard Larocque <rlarocque@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-09-12alarmtimer: Do not signal SIGEV_NONE timersRichard Larocque
Avoids sending a signal to alarm timers created with sigev_notify set to SIGEV_NONE by checking for that special case in the timeout callback. The regular posix timers avoid sending signals to SIGEV_NONE timers by not scheduling any callbacks for them in the first place. Although it would be possible to do something similar for alarm timers, it's simpler to handle this as a special case in the timeout. Prior to this patch, the alarm timer would ignore the sigev_notify value and try to deliver signals to the process anyway. Even worse, the sanity check for the value of sigev_signo is skipped when SIGEV_NONE was specified, so the signal number could be bogus. If sigev_signo was an unitialized value (as it often would be if SIGEV_NONE is used), then it's hard to predict which signal will be sent. Cc: stable@vger.kernel.org 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: Sharvil Nanavati <sharvil@google.com> Signed-off-by: Richard Larocque <rlarocque@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-09-12alarmtimer: Return relative times in timer_gettimeRichard Larocque
Returns the time remaining for an alarm timer, rather than the time at which it is scheduled to expire. If the timer has already expired or it is not currently scheduled, the it_value's members are set to zero. This new behavior matches that of the other posix-timers and the POSIX specifications. This is a change in user-visible behavior, and may break existing applications. Hopefully, few users rely on the old incorrect behavior. Cc: stable@vger.kernel.org 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: Sharvil Nanavati <sharvil@google.com> Signed-off-by: Richard Larocque <rlarocque@google.com> [jstultz: minor style tweak] Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-09-12jiffies: Fix timeval conversion to jiffiesAndrew Hunter
timeval_to_jiffies tried to round a timeval up to an integral number of jiffies, but the logic for doing so was incorrect: intervals corresponding to exactly N jiffies would become N+1. This manifested itself particularly repeatedly stopping/starting an itimer: setitimer(ITIMER_PROF, &val, NULL); setitimer(ITIMER_PROF, NULL, &val); would add a full tick to val, _even if it was exactly representable in terms of jiffies_ (say, the result of a previous rounding.) Doing this repeatedly would cause unbounded growth in val. So fix the math. Here's what was wrong with the conversion: we essentially computed (eliding seconds) jiffies = usec * (NSEC_PER_USEC/TICK_NSEC) by using scaling arithmetic, which took the best approximation of NSEC_PER_USEC/TICK_NSEC with denominator of 2^USEC_JIFFIE_SC = x/(2^USEC_JIFFIE_SC), and computed: jiffies = (usec * x) >> USEC_JIFFIE_SC and rounded this calculation up in the intermediate form (since we can't necessarily exactly represent TICK_NSEC in usec.) But the scaling arithmetic is a (very slight) *over*approximation of the true value; that is, instead of dividing by (1 usec/ 1 jiffie), we effectively divided by (1 usec/1 jiffie)-epsilon (rounding down). This would normally be fine, but we want to round timeouts up, and we did so by adding 2^USEC_JIFFIE_SC - 1 before the shift; this would be fine if our division was exact, but dividing this by the slightly smaller factor was equivalent to adding just _over_ 1 to the final result (instead of just _under_ 1, as desired.) In particular, with HZ=1000, we consistently computed that 10000 usec was 11 jiffies; the same was true for any exact multiple of TICK_NSEC. We could possibly still round in the intermediate form, adding something less than 2^USEC_JIFFIE_SC - 1, but easier still is to convert usec->nsec, round in nanoseconds, and then convert using time*spec*_to_jiffies. This adds one constant multiplication, and is not observably slower in microbenchmarks on recent x86 hardware. Tested: the following program: int main() { struct itimerval zero = {{0, 0}, {0, 0}}; /* Initially set to 10 ms. */ struct itimerval initial = zero; initial.it_interval.tv_usec = 10000; setitimer(ITIMER_PROF, &initial, NULL); /* Save and restore several times. */ for (size_t i = 0; i < 10; ++i) { struct itimerval prev; setitimer(ITIMER_PROF, &zero, &prev); /* on old kernels, this goes up by TICK_USEC every iteration */ printf("previous value: %ld %ld %ld %ld\n", prev.it_interval.tv_sec, prev.it_interval.tv_usec, prev.it_value.tv_sec, prev.it_value.tv_usec); setitimer(ITIMER_PROF, &prev, NULL); } return 0; } Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Paul Turner <pjt@google.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Reviewed-by: Paul Turner <pjt@google.com> Reported-by: Aaron Jacobs <jacobsa@google.com> Signed-off-by: Andrew Hunter <ahh@google.com> [jstultz: Tweaked to apply to 3.17-rc] Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-09-08time, signal: Protect resource use statistics with seqlockRik van Riel
Both times() and clock_gettime(CLOCK_PROCESS_CPUTIME_ID) have scalability issues on large systems, due to both functions being serialized with a lock. The lock protects against reporting a wrong value, due to a thread in the task group exiting, its statistics reporting up to the signal struct, and that exited task's statistics being counted twice (or not at all). Protecting that with a lock results in times() and clock_gettime() being completely serialized on large systems. This can be fixed by using a seqlock around the events that gather and propagate statistics. As an additional benefit, the protection code can be moved into thread_group_cputime(), slightly simplifying the calling functions. In the case of posix_cpu_clock_get_task() things can be simplified a lot, because the calling function already ensures that the task sticks around, and the rest is now taken care of in thread_group_cputime(). This way the statistics reporting code can run lockless. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Daeseok Youn <daeseok.youn@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guillaume Morin <guillaume@morinfr.org> Cc: Ionut Alexa <ionut.m.alexa@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: umgwanakikbuti@gmail.com Cc: fweisbec@gmail.com Cc: srao@redhat.com Cc: lwoodman@redhat.com Cc: atheurer@redhat.com Link: http://lkml.kernel.org/r/20140816134010.26a9b572@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-06timekeeping: Update timekeeper before updating vsyscall and pvclockThomas Gleixner
The update_walltime() code works on the shadow timekeeper to make the seqcount protected region as short as possible. But that update to the shadow timekeeper does not update all timekeeper fields because it's sufficient to do that once before it becomes life. One of these fields is tkr.base_mono. That stays stale in the shadow timekeeper unless an operation happens which copies the real timekeeper to the shadow. The update function is called after the update calls to vsyscall and pvclock. While not correct, it did not cause any problems because none of the invoked update functions used base_mono. commit cbcf2dd3b3d4 (x86: kvm: Make kvm_get_time_and_clockread() nanoseconds based) changed that in the kvm pvclock update function, so the stale mono_base value got used and caused kvm-clock to malfunction. Put the update where it belongs and fix the issue. Reported-by: Chris J Arges <chris.j.arges@canonical.com> Reported-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409050000570.3333@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-09-04nohz: Restore NMI safe local irq work for local nohz kickFrederic Weisbecker
The local nohz kick is currently used by perf which needs it to be NMI-safe. Recent commit though (7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9) changed its implementation to fire the local kick using the remote kick API. It was convenient to make the code more generic but the remote kick isn't NMI-safe. As a result: WARNING: CPU: 3 PID: 18062 at kernel/irq_work.c:72 irq_work_queue_on+0x11e/0x140() CPU: 3 PID: 18062 Comm: trinity-subchil Not tainted 3.16.0+ #34 0000000000000009 00000000903774d1 ffff880244e06c00 ffffffff9a7f1e37 0000000000000000 ffff880244e06c38 ffffffff9a0791dd ffff880244fce180 0000000000000003 ffff880244e06d58 ffff880244e06ef8 0000000000000000 Call Trace: <NMI> [<ffffffff9a7f1e37>] dump_stack+0x4e/0x7a [<ffffffff9a0791dd>] warn_slowpath_common+0x7d/0xa0 [<ffffffff9a07930a>] warn_slowpath_null+0x1a/0x20 [<ffffffff9a17ca1e>] irq_work_queue_on+0x11e/0x140 [<ffffffff9a10a2c7>] tick_nohz_full_kick_cpu+0x57/0x90 [<ffffffff9a186cd5>] __perf_event_overflow+0x275/0x350 [<ffffffff9a184f80>] ? perf_event_task_disable+0xa0/0xa0 [<ffffffff9a01a4cf>] ? x86_perf_event_set_period+0xbf/0x150 [<ffffffff9a187934>] perf_event_overflow+0x14/0x20 [<ffffffff9a020386>] intel_pmu_handle_irq+0x206/0x410 [<ffffffff9a0b54d3>] ? arch_vtime_task_switch+0x63/0x130 [<ffffffff9a01937b>] perf_event_nmi_handler+0x2b/0x50 [<ffffffff9a007b72>] nmi_handle+0xd2/0x390 [<ffffffff9a007aa5>] ? nmi_handle+0x5/0x390 [<ffffffff9a0d131b>] ? lock_release+0xab/0x330 [<ffffffff9a008062>] default_do_nmi+0x72/0x1c0 [<ffffffff9a0c925f>] ? cpuacct_account_field+0xcf/0x200 [<ffffffff9a008268>] do_nmi+0xb8/0x100 Lets fix this by restoring the use of local irq work for the nohz local kick. Reported-by: Catalin Iacob <iacobcatalin@gmail.com> Reported-and-tested-by: Dave Jones <davej@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-08-26scheduler: Replace __get_cpu_var with this_cpu_ptrChristoph Lameter
Convert all uses of __get_cpu_var for address calculation to use this_cpu_ptr instead. [Uses of __get_cpu_var with cpumask_var_t are no longer handled by this patch] Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>