This stresses the lockdep code in some ways specifically useful
to ww_mutexes. It adds checks for most of the common locking
errors.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: robclark@gmail.com
Cc: rostedt@goodmis.org
Cc: daniel@ffwll.ch
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20130620113124.4001.23186.stgit@patserSigned-off-by: Ingo Molnar <mingo@kernel.org>

Injects EDEADLK conditions at pseudo-random interval, with
exponential backoff up to UINT_MAX (to ensure that every lock
operation still completes in a reasonable time).

This way we can test the wound slowpath even for ww mutex users
where contention is never expected, and the ww deadlock
avoidance algorithm is only needed for correctness against
malicious userspace. An example would be protecting kernel
modesetting properties, which thanks to single-threaded X isn't
really expected to contend, ever.

I've looked into using the CONFIG_FAULT_INJECTION
infrastructure, but decided against it for two reasons:

- EDEADLK handling is mandatory for ww mutex users and should
  never affect the outcome of a syscall. This is in contrast to -ENOMEM
  injection. So fine configurability isn't required.

- The fault injection framework only allows to set a simple
  probability for failure. Now the probability that a ww mutex acquire
  stage with N locks will never complete (due to too many injected
  EDEADLK backoffs) is zero. But the expected number of ww_mutex_lock
  operations for the completely uncontended case would be O(exp(N)).
  The per-acuiqire ctx exponential backoff solution choosen here only
  results in O(log N) overhead due to injection and so O(log N * N)
  lock operations. This way we can fail with high probability (and so
  have good test coverage even for fancy backoff and lock acquisition
  paths) without running into patalogical cases.

Note that EDEADLK will only ever be injected when we managed to
acquire the lock. This prevents any behaviour changes for users
which rely on the EALREADY semantics.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: rostedt@goodmis.org
Cc: daniel@ffwll.ch
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20130620113117.4001.21681.stgit@patserSigned-off-by: Ingo Molnar <mingo@kernel.org>

Wound/wait mutexes are used when other multiple lock
acquisitions of a similar type can be done in an arbitrary
order. The deadlock handling used here is called wait/wound in
the RDBMS literature: The older tasks waits until it can acquire
the contended lock. The younger tasks needs to back off and drop
all the locks it is currently holding, i.e. the younger task is
wounded.

For full documentation please read Documentation/ww-mutex-design.txt.

References: https://lwn.net/Articles/548909/Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Rob Clark <robdclark@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: rostedt@goodmis.org
Cc: daniel@ffwll.ch
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/51C8038C.9000106@canonical.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

This will allow me to call functions that have multiple
arguments if fastpath fails. This is required to support ticket
mutexes, because they need to be able to pass an extra argument
to the fail function.

Originally I duplicated the functions, by adding
__mutex_fastpath_lock_retval_arg. This ended up being just a
duplication of the existing function, so a way to test if
fastpath was called ended up being better.

This also cleaned up the reservation mutex patch some by being
able to call an atomic_set instead of atomic_xchg, and making it
easier to detect if the wrong unlock function was previously
used.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: robclark@gmail.com
Cc: rostedt@goodmis.org
Cc: daniel@ffwll.ch
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20130620113105.4001.83929.stgit@patserSigned-off-by: Ingo Molnar <mingo@kernel.org>

Pull s390 fixes from Martin Schwidefsky:
 "A couple of last-minute fixes: a build regression for !SMP, a recent
  memory detection patch caused kdump to break, a regression in regard
  to sscanf vs reboot from FCP, and two fixes in the DMA mapping code
  for PCI"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/ipl: Fix FCP WWPN and LUN format strings for read
  s390/mem_detect: fix memory hole handling
  s390/dma: support debug_dma_mapping_error
  s390/dma: fix mapping_error detection
  s390/irq: Only define synchronize_irq() on SMP

Pull powerpc bugfix from Ben Herrenschmidt:
 "This is a fix for a regression causing a freescale "83xx" based
  platforms to crash on boot due to some PCI breakage"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/pci: Fix boot panic on mpc83xx (regression)

Pull fuse bugfix from Miklos Szeredi:
 "This fixes a race between fallocate() and truncate()"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: hold i_mutex in fuse_file_fallocate()

Pull spi updates from Mark Brown:
 "A few last minute SPI updates: fix a missized allocation and use
  atomic allocations in atomic context in the PXA driver, and fix the
  checking of return codes in the S3C64xx driver which caused spurious
  errors under heavy load."

* tag 'spi-v3.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi/pxa2xx: fix memory corruption due to wrong size used in devm_kzalloc()
  spi/pxa2xx: use GFP_ATOMIC in sg table allocation
  spi: s3c64xx: Fix pm_runtime_get_sync() return value check

The following commit caused a fatal oops when booting on mpc83xx with
a non-express PCI bus (regardless of whether a PCI device is present):

commit 50d8f87d
Author: Rojhalat Ibrahim <imr@rtschenk.de>
Date:   Mon Apr 8 10:15:28 2013 +0200

    powerpc/fsl-pci Make PCIe hotplug work with Freescale PCIe controllers

    Up to now the PCIe link status on Freescale PCIe controllers was only
    checked once at boot time. So hotplug did not work. With this patch the
    link status is checked on every config read. PCIe devices not present at
    boot time are found after doing 'echo 1 >/sys/bus/pci/rescan'.
Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

This patch fixes the issue by calling setup_indirect_pci for all device types.
fsl_indirect_read_config is now only used for booke/86xx PCIe controllers.
Reported-by: Michael Guntsche <mike@it-loops.com>
Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Signed-off-by: Scott Wood <scottwood@freescale.com>

The following git commit changed the behavior of sscanf:

commit 53809751
Author: Jan Beulich <JBeulich@suse.com>
Date:   Mon Dec 17 16:01:31 2012 -0800
    sscanf: don't ignore field widths for numeric conversions

This broke the WWPN and LUN sysfs attributes for s390 reipl and dump
on panic.

Example:

$ echo 0x0123456701234567 > /sys/firmware/reipl/fcp/wwpn
$ cat /sys/firmware/reipl/fcp/wwpn
0x0001234567012345

So fix this and use format strings that work also with the
new sscanf implementation:

$ echo 0x012345670123456789 > /sys/firmware/reipl/fcp/wwpn
$ cat /sys/firmware/reipl/fcp/wwpn
0x0123456701234567

Cc: stable@vger.kernel.org # 3.8+
Reviewed-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Fix new kernel-doc warning in fs/splice.c:

  Warning(fs/splice.c:1298): No description found for parameter 'opos'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull input subsystem updates from Dmitry Torokhov:
 "A few small fixups for cyttsp, wacom and xpad drivers"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: xpad - fix for "Mad Catz Street Fighter IV FightPad" controllers
  Input: wacom - add a new stylus (0x100802) for Intuos5 and Cintiqs
  Input: add missing dependencies on CONFIG_HAS_IOMEM
  Input: cyttsp - fix swapped mfg_stat and mfg_cmd registers
  Input: cyttsp - add missing handshake
  Input: cyttsp - fix memcpy size param

Pull ARM SoC fixes from Arnd Bergmann:
 "These are two fixes that came in this week, one for a regression we
  introduced in 3.10 in the GIC interrupt code, and the other one fixes
  a typo in newly introduced code"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  irqchip: gic: call gic_cpu_init() as well in CPU_STARTING_FROZEN case
  ARM: dts: Correct the base address of pinctrl_3 on Exynos5250

Merge tag 'driver-core-3.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fix from Greg Kroah-Hartman:
 "Here's a single patch for the firmware core that resolves a reported
  oops in the firmware core that people have been hitting."

* tag 'driver-core-3.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  firmware loader: fix use-after-free by double abort

Pull USB fixes from Greg Kroah-Hartman:
 "Here are two USB patches for 3.10.

  One updates the Kconfig wording for CONFIG_USB_PHY to make it,
  hopefully, more obvious what this option is (I know you complained
  about this when it hit the tree.) The other is a new device id for a
  driver"

* tag 'usb-3.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: serial: ti_usb_3410_5052: new device id for Abbot strip port cable
  usb: phy: Improve Kconfig help for CONFIG_USB_PHY

Pul tty fixes from Greg Kroah-Hartman:
 "Here are two tty core fixes that resolve some regressions that have
  been reported recently.  Both tiny fixes, but needed"

* tag 'tty-3.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: Fix transient pty write() EIO
  tty/vt: Return EBUSY if deallocating VT1 and it is busy

Pull SCSI target fixes from Nicholas Bellinger:
 "Included is the recent tcm_qla2xxx residual underrun length fix from
  Roland, along with Joern's iscsi-target patch for session_lock
  breakage within iscsit_stop_time2retain_timer() code.  Both are CC'ed
  to stable.

  The remaining two are specific to recent iscsi-target + iser
  conversion changes.  One drops some left-over debug noise, and Andy's
  patch fixes configfs attribute handling during an explicit network
  portal feature bit disable when iser-target is unsupported."

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  iscsi-target: Remove left over v3.10-rc debug printks
  target/iscsi: Fix op=disable + error handling cases in np_store_iser
  tcm_qla2xxx: Fix residual for underrun commands that fail
  target/iscsi: don't corrupt bh_count in iscsit_stop_time2retain_timer()

Pull media fixes from Mauro Carvalho Chehab:
 "Another set of fixes for Kernel 3.10.

  This series contain:
   - two Kbuild fixes for randconfig
   - a buffer overflow when using rtl28xuu with r820t tuner
   - one clk fixup on exynos4-is driver"

* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  [media] Fix build when drivers are builtin and frontend modules
  [media] s5p makefiles: don't override other selections on obj-[ym]
  [media] exynos4-is: Fix FIMC-IS clocks initialization
  [media] rtl28xxu: fix buffer overflow when probing Rafael Micro r820t tuner

Pull vfs fixes from Al Viro:
 "Several fixes for bugs caught while looking through f_pos (ab)users"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  aout32 coredump compat fix
  splice: don't pass the address of ->f_pos to methods
  mconsole: we'd better initialize pos before passing it to vfs_read()...

dump_seek() does SEEK_CUR, not SEEK_SET; native binfmt_aout
handles it correctly (seeks by PAGE_SIZE - sizeof(struct user),
getting the current position to PAGE_SIZE), compat one seeks
by PAGE_SIZE and ends up at PAGE_SIZE + already written...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull x86 fixes from Peter Anvin:
 "This series fixes a couple of build failures, and fixes MTRR cleanup
  and memory setup on very specific memory maps.

  Finally, it fixes triggering backtraces on all CPUs, which was
  inadvertently disabled on x86."

* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Fix dummy variable buffer allocation
  x86: Fix trigger_all_cpu_backtrace() implementation
  x86: Fix section mismatch on load_ucode_ap
  x86: fix build error and kconfig for ia32_emulation and binfmt
  range: Do not add new blank slot with add_range_with_merge
  x86, mtrr: Fix original mtrr range get for mtrr_cleanup

Pull drm radeon fixes from Dave Airlie:
 "One core fix, but mostly radeon fixes for s/r and big endian UVD
  support, and a fix to stop the GPU being reset for no good reason, and
  crashing people's machines."

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: update lockup tracking when scheduling in empty ring
  drm/prime: Honor requested file flags when exporting a buffer
  drm/radeon: fix UVD on big endian
  drm/radeon: fix write back suspend regression with uvd v2
  drm/radeon: do not try to uselessly update virtual memory pagetable

Pull ACPI fixes from Rafael Wysocki:

 - Fix for a regression causing a failure to turn on some devices on
   some systems during initialization introduced by a recent revert of
   an ACPI PM change that broke something else.  Fortunately, we know
   exactly what devices are affected, so we can add a fix just for them
   leaving everyone else alone.

 - ACPI power resources initialization fix preventing a NULL pointer
   from being dereferenced in the acpi_add_power_resource() error code
   path.

 - ACPI dock station driver fix that adds missing locking to
   write_undock().

 - ACPI resources allocation fix changing the scope of an old workaround
   so that it doesn't affect systems that aren't actually buggy.  This
   was reported a couple of days ago to fix DMA problems on some new
   platforms so we need it in -stable.  From Mika Westerberg.

* tag 'acpi-3.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / LPSS: Power up LPSS devices during enumeration
  ACPI / PM: Fix error code path for power resources initialization
  ACPI / dock: Take ACPI scan lock in write_undock()
  ACPI / resources: call acpi_get_override_irq() only for legacy IRQ resources

Pull KVM fixes from Paolo Bonzini:
 "Three one-line fixes for my first pull request; one for x86 host, one
  for x86 guest, one for PPC"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  x86: kvmclock: zero initialize pvclock shared memory area
  kvm/ppc/booke: Delay kvmppc_lazy_ee_enable
  KVM: x86: remove vcpu's CPL check in host-invoked XCR set

Pull crypto fix from Herbert Xu:
 "This fixes an unaligned crash in XTS mode when using aseni_intel"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: aesni_intel - fix accessing of unaligned memory

Pull Ceph fix from Sage Weil:
 "This fixes a problem preventing the kernel and userland librbd
  libraries from sharing data with the new format 2 images"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  rbd: use the correct length for format 2 object names

 * Don't leak random kernel memory to EFI variable NVRAM when attempting
   to initiate garbage collection. Also, free the kernel memory when
   we're done with it instead of leaking - Ben Hutchings
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

ACPI part of the driver accidentally used sizeof(*ssp) instead of the
correct sizeof(*pdata). This leads to nasty memory corruptions like the one
below:

    BUG: unable to handle kernel paging request at 0000000749fd30b8
    IP: [<ffffffff813fe8a1>] __list_del_entry+0x31/0xd0
    PGD 0
    Oops: 0000 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 0 PID: 30 Comm: kworker/0:1 Not tainted 3.10.0-rc6v3.10-rc6_sdhci_modprobe+ #443
    task: ffff8801483a0940 ti: ffff88014839e000 task.ti: ffff88014839e000
    RIP: 0010:[<ffffffff813fe8a1>]  [<ffffffff813fe8a1>] __list_del_entry+0x31/0xd0
    RSP: 0000:ffff88014839fde8  EFLAGS: 00010046
    RAX: ffff880149fd30b0 RBX: ffff880149fd3040 RCX: dead000000200200
    RDX: 0000000749fd30b0 RSI: ffff880149fd3058 RDI: ffff88014834d640
    RBP: ffff88014839fde8 R08: ffff88014834d640 R09: 0000000000000001
    R10: ffff8801483a0940 R11: 0000000000000001 R12: ffff880149fd3040
    R13: ffffffff810e0b30 R14: ffff8801483a0940 R15: ffff88014834d640
    FS:  0000000000000000(0000) GS:ffff880149e00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000168 CR3: 0000000001e0b000 CR4: 00000000001407f0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    Stack:
     ffff88014839fe48 ffffffff810e0baf ffffffff81120abd ffff88014839fe20
     ffff8801483a0940 ffff8801483a0940 ffff8801483a0940 ffff8801486b1c90
     ffff88014834d640 ffffffff810e0b30 0000000000000000 0000000000000000
    Call Trace:
     [<ffffffff810e0baf>] worker_thread+0x7f/0x390
     [<ffffffff81120abd>] ? trace_hardirqs_on+0xd/0x10
     [<ffffffff810e0b30>] ? manage_workers.isra.22+0x2b0/0x2b0
     [<ffffffff810e6c09>] kthread+0xd9/0xe0
     [<ffffffff810f93df>] ? local_clock+0x3f/0x50
     [<ffffffff810e6b30>] ? kthread_create_on_node+0x110/0x110
     [<ffffffff818c5dec>] ret_from_fork+0x7c/0xb0
     [<ffffffff810e6b30>] ? kthread_create_on_node+0x110/0x110

Fix this by using the right structure size in devm_kzalloc().
Reported-by: Jerome Blin <jerome.blin@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org # 3.9+

1. Check for allocation failure
2. Clear the buffer contents, as they may actually be written to flash
3. Don't leak the buffer

Compile-tested only.

[ Tested successfully on my buggy ASUS machine - Matt ]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Reported-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Writing 0 when iser was not previously enabled, so succeed but do
nothing so that user-space code doesn't need a try: catch block
when ib_isert logic is not available.

Also, return actual error from add_network_portal using PTR_ERR
during op=enable failure.
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

One user visible fix to stop misreport GPU hangs and subsequent resets.
* 'drm-fixes-3.10' of git://people.freedesktop.org/~agd5f/linux:
  drm/radeon: update lockup tracking when scheduling in empty ring

There might be issue with lockup detection when scheduling on an
empty ring that have been sitting idle for a while. Thus update
the lockup tracking data when scheduling new work in an empty ring.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Tested-by: Andy Lutomirski <luto@amacapital.net>
Cc: stable@vger.kernel.org
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Pull scheduler fixes from Ingo Molnar:
 "Two smaller fixes - plus a context tracking tracing fix that is a bit
  bigger"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tracing/context-tracking: Add preempt_schedule_context() for tracing
  sched: Fix clear NOHZ_BALANCE_KICK
  sched/x86: Construct all sibling maps if smt

Pull perf fixes from Ingo Molnar:
 "Four fixes.  The mmap ones are unfortunately larger than desired -
  fuzzing uncovered bugs that needed perf context life time management
  changes to fix properly"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix broken PEBS-LL support on SNB-EP/IVB-EP
  perf: Fix mmap() accounting hole
  perf: Fix perf mmap bugs
  kprobes: Fix to free gone and unused optprobes

Pull cpu idle fixes from Thomas Gleixner:
 - Add a missing irq enable. Fallout of the idle conversion
 - Fix stackprotector wreckage caused by the idle conversion

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  idle: Enable interrupts in the weak arch_cpu_idle() implementation
  idle: Add the stack canary init to cpu_startup_entry()

Pull timer fixes from Thomas Gleixner:
 - Fix inconstinant clock usage in virtual time accounting
 - Fix a build error in KVM caused by the NOHZ work
 - Remove a pointless timekeeping duty assignment which breaks NOHZ
 - Use a proper notifier return value to avoid random behaviour

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick: Remove useless timekeeping duty attribution to broadcast source
  nohz: Fix notifier return val that enforce timekeeping
  kvm: Move guest entry/exit APIs to context_tracking
  vtime: Use consistent clocks among nohz accounting