When userspace sends KVM_SET_LAPIC, KVM schedules a check between
the vCPU's IRR and ISR and the IOAPIC redirection table, in order
to re-establish the IOAPIC's dest_map (the list of CPUs servicing
the real-time clock interrupt with the corresponding vectors).

However, __rtc_irq_eoi_tracking_restore_one was forgetting to
set dest_map->vectors.  Because of this, the IOAPIC did not process
the real-time clock interrupt EOI, ioapic->rtc_status.pending_eoi
got stuck at a non-zero value, and further RTC interrupts were
reported to userspace as coalesced.

Fixes: 9e4aabe2
Fixes: 4d99ba89
Cc: stable@vger.kernel.org
Cc: Joerg Roedel <jroedel@suse.de>
Cc: David Gilbert <dgilbert@redhat.com>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Pull uaccess fixes from Al Viro:
 "Fixes for broken uaccess primitives - mostly lack of proper zeroing
  in copy_from_user()/get_user()/__get_user(), but for several
  architectures there's more (broken clear_user() on frv and
  strncpy_from_user() on hexagon)"

* 'uaccess-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  avr32: fix copy_from_user()
  microblaze: fix __get_user()
  microblaze: fix copy_from_user()
  m32r: fix __get_user()
  blackfin: fix copy_from_user()
  sparc32: fix copy_from_user()
  sh: fix copy_from_user()
  sh64: failing __get_user() should zero
  score: fix copy_from_user() and friends
  score: fix __get_user/get_user
  s390: get_user() should zero on failure
  ppc32: fix copy_from_user()
  parisc: fix copy_from_user()
  openrisc: fix copy_from_user()
  nios2: fix __get_user()
  nios2: copy_from_user() should zero the tail of destination
  mn10300: copy_from_user() should zero on access_ok() failure...
  mn10300: failing __get_user() and get_user() should zero
  mips: copy_from_user() must zero the destination on access_ok() failure
  ARC: uaccess: get_user to zero out dest in cause of fault
  ...

Pull xen regression fix from David Vrabel:
 "Fix SMP boot in arm guests"

* tag 'for-linus-4.8b-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  arm/xen: fix SMP guests boot

Commit 88e957d6 ("xen: introduce xen_vcpu_id mapping") broke SMP
ARM guests on Xen. When FIFO-based event channels are in use (this is
the default), evtchn_fifo_alloc_control_block() is called on
CPU_UP_PREPARE event and this happens before we set up xen_vcpu_id
mapping in xen_starting_cpu. Temporary fix the issue by setting direct
Linux CPU id <-> Xen vCPU id mapping for all possible CPUs at boot. We
don't currently support kexec/kdump on Xen/ARM so these ids always
match.

In future, we have several ways to solve the issue, e.g.:

- Eliminate all hypercalls from CPU_UP_PREPARE, do them from the
  starting CPU. This can probably be done for both x86 and ARM and, if
  done, will allow us to get Xen's idea of vCPU id from CPUID/MPIDR on
  the starting CPU directly, no messing with ACPI/device tree
  required.

- Save vCPU id information from ACPI/device tree on ARM and use it to
  initialize xen_vcpu_id mapping. This is the same trick we currently
  do on x86.
Reported-by: NJulien Grall <julien.grall@arm.com>
Tested-by: NWei Chen <Wei.Chen@arm.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: NStefano Stabellini <sstabellini@kernel.org>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

really ugly, but apparently avr32 compilers turns access_ok() into
something so bad that they want it in assembler.  Left that way,
zeroing added in inline wrapper.

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It could be done in exception-handling bits in __get_user_b() et.al.,
but the surgery involved would take more knowledge of sh64 details
than I have or _want_ to have.

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* should zero on any failure
* __get_user() should use __copy_from_user(), not copy_from_user()

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

should clear on access_ok() failures.  Also remove the useless
range truncation logics.

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... that should zero on faults.  Also remove the <censored> helpful
logics wrt range truncation copied from ppc32.  Where it had ever
been needed only in case of copy_from_user() *and* had not been merged
into the mainline until a month after the need had disappeared.
A decade before openrisc went into mainline, I might add...

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

a) should not leave crap on fault
b) should _not_ require access_ok() in any cases.

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Al reported potential issue with ARC get_user() as it wasn't clearing
out destination pointer in case of fault due to bad address etc.

Verified using following

| {
|  	u32 bogus1 = 0xdeadbeef;
|	u64 bogus2 = 0xdead;
|	int rc1, rc2;
|
|  	pr_info("Orig values %x %llx\n", bogus1, bogus2);
|	rc1 = get_user(bogus1, (u32 __user *)0x40000000);
|	rc2 = get_user(bogus2, (u64 __user *)0x50000000);
|	pr_info("access %d %d, new values %x %llx\n",
|		rc1, rc2, bogus1, bogus2);
| }

| [ARCLinux]# insmod /mnt/kernel-module/qtn.ko
| Orig values deadbeef dead
| access -14 -14, new values 0 0
Reported-by: NAl Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Acked-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It's -EFAULT, not -1 (and contrary to the comment in there,
__strnlen_user() can return 0 - on faults).

Cc: stable@vger.kernel.org
Acked-by: NRichard Kuo <rkuo@codeaurora.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It should check access_ok().  Otherwise a bunch of places turn into
trivially exploitable rootholes.

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* copy_from_user() on access_ok() failure ought to zero the destination
* none of those primitives should skip the access_ok() check in case of
small constant size.

Cc: stable@vger.kernel.org
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

both for access_ok() failures and for faults halfway through

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pull x86 fixes from Ingo Molnar:
 "Three fixes:

   - AMD microcode loading fix with randomization

   - an lguest tooling fix

   - and an APIC enumeration boundary condition fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/apic: Fix num_processors value in case of failure
  tools/lguest: Don't bork the terminal in case of wrong args
  x86/microcode/AMD: Fix load of builtin microcode with randomized memory

Pull scheduler fix from Ingo Molnar:
 "A try_to_wake_up() memory ordering race fix causing a busy-loop in
  ttwu()"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Fix a race between try_to_wake_up() and a woken up task

Pull perf fixes from Ingo Molnar:
 "This contains:

   - a set of fixes found by directed-random perf fuzzing efforts by
     Vince Weaver, Alexander Shishkin and Peter Zijlstra

   - a cqm driver crash fix

   - an AMD uncore driver use after free fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Fix PEBSv3 record drain
  perf/x86/intel/bts: Kill a silly warning
  perf/x86/intel/bts: Fix BTS PMI detection
  perf/x86/intel/bts: Fix confused ordering of PMU callbacks
  perf/core: Fix aux_mmap_count vs aux_refcount order
  perf/core: Fix a race between mmap_close() and set_output() of AUX events
  perf/x86/amd/uncore: Prevent use after free
  perf/x86/intel/cqm: Check cqm/mbm enabled state in event init
  perf/core: Remove WARN from perf_event_read()

Pull locking fix from Ingo Molnar:
 "Another lockless_dereference() Sparse fix"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/barriers: Don't use sizeof(void) in lockless_dereference()

Pull EFI fixes from Ingo Molnar:
 "This contains a Xen fix, an arm64 fix and a race condition /
  robustization set of fixes related to ExitBootServices() usage and
  boundary conditions"

* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Use efi_exit_boot_services()
  efi/libstub: Use efi_exit_boot_services() in FDT
  efi/libstub: Introduce ExitBootServices helper
  efi/libstub: Allocate headspace in efi_get_memory_map()
  efi: Fix handling error value in fdt_find_uefi_params
  efi: Make for_each_efi_memory_desc_in_map() cope with running on Xen

Pull MD fixes from Shaohua Li:
 "A few bug fixes for MD:

   - Guoqing fixed a bug compiling md-cluster in kernel

   - I fixed a potential deadlock in raid5-cache superblock write, a
     hang in raid5 reshape resume and a race condition introduced in
     rc4"

* tag 'md/4.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  raid5: fix a small race condition
  md-cluster: make md-cluster also can work when compiled into kernel
  raid5: guarantee enough stripes to avoid reshape hang
  raid5-cache: fix a deadlock in superblock write

Pull crypto bugfix from Herbert Xu:
 "Fix a bug in the cryptd code that may lead to crashes"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: cryptd - initialize child shash_desc on import

Pull clk fixes from Stephen Boyd:
 "Some small fixes for the new sunxi clk driver introduced this merge
  window"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: sunxi-ng: Fix wrong reset register offsets
  clk: sunxi-ng: nk: Make ccu_nk_find_best static
  clk: sunxi-ng: Fix inverted test condition in ccu_helper_wait_for_lock
  clk: sunxi: Fix return value check in sun8i_a23_mbus_setup()
  clk: sunxi: pll2: Fix return value check in sun4i_pll2_setup()

Pull KVM fixes from Paolo Bonzini:
 - s390: nested virt fixes (new 4.8 feature)
 - x86: fixes for 4.8 regressions
 - ARM: two small bugfixes

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm-arm: Unmap shadow pagetables properly
  x86, clock: Fix kvm guest tsc initialization
  arm: KVM: Fix idmap overlap detection when the kernel is idmap'ed
  KVM: lapic: adjust preemption timer correctly when goes TSC backward
  KVM: s390: vsie: fix riccbd
  KVM: s390: don't use current->thread.fpu.* when accessing registers

Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

  Stable patches:
   - We must serialise LAYOUTGET and LAYOUTRETURN to ensure correct
     state accounting
   - Fix the CREATE_SESSION slot number

  Bugfixes:
   - sunrpc: fix a UDP memory accounting regression
   - NFS: Fix an error reporting regression in nfs_file_write()
   - pNFS: Fix further layout stateid issues
   - RPC/rdma: Revert 3d4cf35b ("xprtrdma: Reply buffer
     exhaustion...")
   - RPC/rdma: Fix receive buffer accounting"

* tag 'nfs-for-4.8-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv4.1: Fix the CREATE_SESSION slot number accounting
  xprtrdma: Fix receive buffer accounting
  xprtrdma: Revert 3d4cf35b ("xprtrdma: Reply buffer exhaustion...")
  pNFS: Don't forget the layout stateid if there are outstanding LAYOUTGETs
  pNFS: Clear out all layout segments if the server unsets lrp->res.lrs_present
  pNFS: Fix pnfs_set_layout_stateid() to clear NFS_LAYOUT_INVALID_STID
  pNFS: Ensure LAYOUTGET and LAYOUTRETURN are properly serialised
  NFS: Fix error reporting in nfs_file_write()
  sunrpc: fix UDP memory accounting