This reverts commit 85c8555f ("KVM: check for !is_zero_pfn() in
kvm_is_mmio_pfn()") and renames the function to kvm_is_reserved_pfn.

The problem being addressed by the patch above was that some ARM code
based the memory mapping attributes of a pfn on the return value of
kvm_is_mmio_pfn(), whose name indeed suggests that such pfns should
be mapped as device memory.

However, kvm_is_mmio_pfn() doesn't do quite what it says on the tin,
and the existing non-ARM users were already using it in a way which
suggests that its name should probably have been 'kvm_is_reserved_pfn'
from the beginning, e.g., whether or not to call get_page/put_page on
it etc. This means that returning false for the zero page is a mistake
and the patch above should be reverted.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Instead of using kvm_is_mmio_pfn() to decide whether a host region
should be stage 2 mapped with device attributes, add a new static
function kvm_is_device_pfn() that disregards RAM pages with the
reserved bit set, as those should usually not be mapped as device
memory.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

If we detect another vCPU is running we just exit and return 0 as if we
succesfully created the VGIC, but the VGIC wouldn't actual be created.

This shouldn't break in-kernel behavior because the kernel will not
observe the failed the attempt to create the VGIC, but userspace could
be rightfully confused.

Cc: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When running on a system with a GICv3, we currenly don't allow the guest
to access the system register interface of the GICv3.  We do this by
clearing the ICC_SRE_EL2.Enable, which causes all guest accesses to
ICC_SRE_EL1 to trap to EL2 and causes all guest accesses to other ICC_
registers to cause an undefined exception in the guest.

However, we currently don't handle the trap of guest accesses to
ICC_SRE_EL1 and will spill out a warning.  The trap just needs to handle
the access as RAZ/WI, and a guest that tries to prod this register and
set ICC_SRE_EL1.SRE=1, must read back the value (which Linux already
does) to see if it succeeded, and will thus observe that ICC_SRE_EL1.SRE
was not set.

Add the simple trap handler in the sorted table of the system registers.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
[ardb: added cp15 handling]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Currently if using a 48-bit VA, tearing down the hyp page tables (which
can happen in the absence of a GICH or GICV resource) results in the
rather nasty splat below, evidently becasue we access a table that
doesn't actually exist.

Commit 38f791a4 (arm64: KVM: Implement 48 VA support for KVM EL2
and Stage-2) added a pgd_none check to __create_hyp_mappings to account
for the additional level of tables, but didn't add a corresponding check
to unmap_range, and this seems to be the source of the problem.

This patch adds the missing pgd_none check, ensuring we don't try to
access tables that don't exist.

Original splat below:

kvm [1]: Using HYP init bounce page @83fe94a000
kvm [1]: Cannot obtain GICH resource
Unable to handle kernel paging request at virtual address ffff7f7fff000000
pgd = ffff800000770000
[ffff7f7fff000000] *pgd=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.18.0-rc2+ #89
task: ffff8003eb500000 ti: ffff8003eb45c000 task.ti: ffff8003eb45c000
PC is at unmap_range+0x120/0x580
LR is at free_hyp_pgds+0xac/0xe4
pc : [<ffff80000009b768>] lr : [<ffff80000009cad8>] pstate: 80000045
sp : ffff8003eb45fbf0
x29: ffff8003eb45fbf0 x28: ffff800000736000
x27: ffff800000735000 x26: ffff7f7fff000000
x25: 0000000040000000 x24: ffff8000006f5000
x23: 0000000000000000 x22: 0000007fffffffff
x21: 0000800000000000 x20: 0000008000000000
x19: 0000000000000000 x18: ffff800000648000
x17: ffff800000537228 x16: 0000000000000000
x15: 000000000000001f x14: 0000000000000000
x13: 0000000000000001 x12: 0000000000000020
x11: 0000000000000062 x10: 0000000000000006
x9 : 0000000000000000 x8 : 0000000000000063
x7 : 0000000000000018 x6 : 00000003ff000000
x5 : ffff800000744188 x4 : 0000000000000001
x3 : 0000000040000000 x2 : ffff800000000000
x1 : 0000007fffffffff x0 : 000000003fffffff

Process swapper/0 (pid: 1, stack limit = 0xffff8003eb45c058)
Stack: (0xffff8003eb45fbf0 to 0xffff8003eb460000)
fbe0:                                     eb45fcb0 ffff8003 0009cad8 ffff8000
fc00: 00000000 00000080 00736140 ffff8000 00736000 ffff8000 00000000 00007c80
fc20: 00000000 00000080 006f5000 ffff8000 00000000 00000080 00743000 ffff8000
fc40: 00735000 ffff8000 006d3030 ffff8000 006fe7b8 ffff8000 00000000 00000080
fc60: ffffffff 0000007f fdac1000 ffff8003 fd94b000 ffff8003 fda47000 ffff8003
fc80: 00502b40 ffff8000 ff000000 ffff7f7f fdec6000 00008003 fdac1630 ffff8003
fca0: eb45fcb0 ffff8003 ffffffff 0000007f eb45fd00 ffff8003 0009b378 ffff8000
fcc0: ffffffea 00000000 006fe000 ffff8000 00736728 ffff8000 00736120 ffff8000
fce0: 00000040 00000000 00743000 ffff8000 006fe7b8 ffff8000 0050cd48 00000000
fd00: eb45fd60 ffff8003 00096070 ffff8000 006f06e0 ffff8000 006f06e0 ffff8000
fd20: fd948b40 ffff8003 0009a320 ffff8000 00000000 00000000 00000000 00000000
fd40: 00000ae0 00000000 006aa25c ffff8000 eb45fd60 ffff8003 0017ca44 00000002
fd60: eb45fdc0 ffff8003 0009a33c ffff8000 006f06e0 ffff8000 006f06e0 ffff8000
fd80: fd948b40 ffff8003 0009a320 ffff8000 00000000 00000000 00735000 ffff8000
fda0: 006d3090 ffff8000 006aa25c ffff8000 00735000 ffff8000 006d3030 ffff8000
fdc0: eb45fdd0 ffff8003 000814c0 ffff8000 eb45fe50 ffff8003 006aaac4 ffff8000
fde0: 006ddd90 ffff8000 00000006 00000000 006d3000 ffff8000 00000095 00000000
fe00: 006a1e90 ffff8000 00735000 ffff8000 006d3000 ffff8000 006aa25c ffff8000
fe20: 00735000 ffff8000 006d3030 ffff8000 eb45fe50 ffff8003 006fac68 ffff8000
fe40: 00000006 00000006 fe293ee6 ffff8003 eb45feb0 ffff8003 004f8ee8 ffff8000
fe60: 004f8ed4 ffff8000 00735000 ffff8000 00000000 00000000 00000000 00000000
fe80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
fea0: 00000000 00000000 00000000 00000000 00000000 00000000 000843d0 ffff8000
fec0: 004f8ed4 ffff8000 00000000 00000000 00000000 00000000 00000000 00000000
fee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ff00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ff20: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ff40: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ff60: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ff80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffa0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000005 00000000
ffe0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Call trace:
[<ffff80000009b768>] unmap_range+0x120/0x580
[<ffff80000009cad4>] free_hyp_pgds+0xa8/0xe4
[<ffff80000009b374>] kvm_arch_init+0x268/0x44c
[<ffff80000009606c>] kvm_init+0x24/0x260
[<ffff80000009a338>] arm_init+0x18/0x24
[<ffff8000000814bc>] do_one_initcall+0x88/0x1a0
[<ffff8000006aaac0>] kernel_init_freeable+0x148/0x1e8
[<ffff8000004f8ee4>] kernel_init+0x10/0xd4
Code: 8b000263 92628479 d1000720 eb01001f (f9400340)
---[ end trace 3bc230562e926fa4 ]---
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jungseok Lee <jungseoklee85@gmail.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull nfsd bugfixes from Bruce Fields:
 "These fix one mishandling of the case when security labels are
  configured out, and two races in the 4.1 backchannel code"

* 'for-3.18' of git://linux-nfs.org/~bfields/linux:
  nfsd: Fix slot wake up race in the nfsv4.1 callback code
  SUNRPC: Fix locking around callback channel reply receive
  nfsd: correctly define v4.2 support attributes

Pull aio fix from Ben LaHaise:
 "Dirty page accounting fix for aio"

* git://git.kvack.org/~bcrl/aio-fixes:
  aio: fix uncorrent dirty pages accouting when truncating AIO ring buffer

Pull powerpc fixes from Ben Herrenschmidt:
 "This series fix a nasty issue with radeon adapters on powerpc servers,
  it's all CC'ed stable and has the relevant maintainers ack's/reviews.

  Basically, some (radeon) adapters have issues with MSI addresses above
  1T (only support 40-bits).  We had powerpc specific quirk but it only
  listed a specific revision of an adapter that we shipped with our
  machines and didn't properly handle the audio function which some
  distros enable nowadays.

  So we made the quirk generic and fixed both the graphic and audio
  drivers properly to use it.

  Without that, ppc64 server machines will crash at boot with a radeon
  adapter.

  Note: This has been brewing for a while, it just needed a last respin
  which got delayed due to us moving ozlabs to a new location in town
  and other such things taking priority"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/pci: Remove unused force_32bit_msi quirk
  powerpc/pseries: Honor the generic "no_64bit_msi" flag
  powerpc/powernv: Honor the generic "no_64bit_msi" flag
  sound/radeon: Move 64-bit MSI quirk from arch to driver
  gpu/radeon: Set flag to indicate broken 64-bit MSI
  PCI/MSI: Add device flag indicating that 64-bit MSIs don't work
  ALSA: hda - Limit 40bit DMA for AMD HDMI controllers

Merge tag 'hwmon-for-linus-v3.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull a hwmon fix from Guenter Roeck:
 "Fix hwmon registration problem in g762 driver"

* tag 'hwmon-for-linus-v3.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (g762) fix call to devm_hwmon_device_register_with_groups()

Pull clock fixes from Mike Turquette:
 "The fixes for the clock framework are all regressions in drivers, plus
  a single fix in one of the basic clock templates.  No fixes to the
  core this time around.

  As with most clock driver fixes these run the gamut from fixing a
  build warning to fixing wrecked memory timings, with a little USB
  tossed in for fun"

* tag 'clk-fixes-for-linus' of https://git.linaro.org/people/mike.turquette/linux:
  clk: pxa: fix pxa27x CCCR bit usage
  clk-divider: Fix READ_ONLY when divider > 1
  clk: qcom: Fix duplicate rbcpr clock name
  clk: at91: usb: fix at91sam9x5 recalc, round and set rate
  clk: at91: usb: fix at91rm9200 round and set rate

This is now fully replaced with the generic "no_64bit_msi" one
that is set by the respective drivers directly.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Instead of the arch specific quirk which we are deprecating
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org>

Instead of the arch specific quirk which we are deprecating
and that drivers don't understand.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org>

A number of radeon cards have a HW limitation causing them to be
unable to generate the full 64-bit of address bits for MSIs. This
breaks MSIs on some platforms such as POWER machines.

We used to have a powerpc specific quirk to address that on a
single card, but this doesn't scale very well, this is better
put under control of the drivers who know precisely what a given
HW revision can do.

We now have a generic quirk in the PCI code. We should set it
appropriately for all radeon's from the audio driver.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
CC: <stable@vger.kernel.org>

Some radeon ASICs don't support all 64 address bits of MSIs despite
advertising support for 64-bit MSIs in their configuration space.

This breaks on systems such as IBM POWER7/8, where 64-bit MSIs can
be assigned with some of the high address bits set.

This makes use of the newly introduced "no_64bit_msi" flag in structure
pci_dev to allow the MSI allocation code to fallback to 32-bit MSIs
on those adapters.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
CC: <stable@vger.kernel.org>
---

Adding Alex's review tag. Patch to the driver is identical to the
reviewed one, I dropped the arch/powerpc hunk rewrote the subject
and cset comment.

This can be set by quirks/drivers to be used by the architecture code
that assigns the MSI addresses.

We additionally add verification in the core MSI code that the values
assigned by the architecture do satisfy the limitation in order to fail
gracefully if they don't (ie. the arch hasn't been updated to deal with
that quirk yet).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

AMD/ATI HDMI controller chip models, we already have a filter to lower
to 32bit DMA, but the rest are supposed to be working with 64bit
although the hardware doesn't really work with 63bit but only with 40
or 48bit DMA.  In this patch, we take 40bit DMA for safety for the
AMD/ATI controllers as the graphics drivers does.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org>

x86 call do_notify_resume on paranoid returns if TIF_UPROBE is set but
not on non-paranoid returns.  I suspect that this is a mistake and that
the code only works because int3 is paranoid.

Setting _TIF_NOTIFY_RESUME in the uprobe code was probably a workaround
for the x86 bug.  With that bug fixed, we can remove _TIF_NOTIFY_RESUME
from the uprobes code.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Chris bisected a NULL pointer deference in task_sched_runtime() to
commit 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime()
inconsistency'.

Chris observed crashes in atop or other /proc walking programs when he
started fork bombs on his machine.  He assumed that this is a new exit
race, but that does not make any sense when looking at that commit.

What's interesting is that, the commit provides update_curr callbacks
for all scheduling classes except stop_task and idle_task.

While nothing can ever hit that via the clock_nanosleep() and
clock_gettime() interfaces, which have been the target of the commit in
question, the author obviously forgot that there are other code paths
which invoke task_sched_runtime()

do_task_stat(()
 thread_group_cputime_adjusted()
   thread_group_cputime()
     task_cputime()
       task_sched_runtime()
        if (task_current(rq, p) && task_on_rq_queued(p)) {
          update_rq_clock(rq);
          up->sched_class->update_curr(rq);
        }

If the stats are read for a stomp machine task, aka 'migration/N' and
that task is current on its cpu, this will happily call the NULL pointer
of stop_task->update_curr.  Ooops.

Chris observation that this happens faster when he runs the fork bomb
makes sense as the fork bomb will kick migration threads more often so
the probability to hit the issue will increase.

Add the missing update_curr callbacks to the scheduler classes stop_task
and idle_task.  While idle tasks cannot be monitored via /proc we have
other means to hit the idle case.

Fixes: 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency'
Reported-by: Chris Mason <clm@fb.com>
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge x86-64 iret fixes from Andy Lutomirski:
 "This addresses the following issues:

   - an unrecoverable double-fault triggerable with modify_ldt.
   - invalid stack usage in espfix64 failed IRET recovery from IST
     context.
   - invalid stack usage in non-espfix64 failed IRET recovery from IST
     context.

  It also makes a good but IMO scary change: non-espfix64 failed IRET
  will now report the correct error.  Hopefully nothing depended on the
  old incorrect behavior, but maybe Wine will get confused in some
  obscure corner case"

* emailed patches from Andy Lutomirski <luto@amacapital.net>:
  x86_64, traps: Rework bad_iret
  x86_64, traps: Stop using IST for #SS
  x86_64, traps: Fix the espfix64 #DF fixup and rewrite it in C

It's possible for iretq to userspace to fail.  This can happen because
of a bad CS, SS, or RIP.

Historically, we've handled it by fixing up an exception from iretq to
land at bad_iret, which pretends that the failed iret frame was really
the hardware part of #GP(0) from userspace.  To make this work, there's
an extra fixup to fudge the gs base into a usable state.

This is suboptimal because it loses the original exception.  It's also
buggy because there's no guarantee that we were on the kernel stack to
begin with.  For example, if the failing iret happened on return from an
NMI, then we'll end up executing general_protection on the NMI stack.
This is bad for several reasons, the most immediate of which is that
general_protection, as a non-paranoid idtentry, will try to deliver
signals and/or schedule from the wrong stack.

This patch throws out bad_iret entirely.  As a replacement, it augments
the existing swapgs fudge into a full-blown iret fixup, mostly written
in C.  It's should be clearer and more correct.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On a 32-bit kernel, this has no effect, since there are no IST stacks.

On a 64-bit kernel, #SS can only happen in user code, on a failed iret
to user space, a canonical violation on access via RSP or RBP, or a
genuine stack segment violation in 32-bit kernel code.  The first two
cases don't need IST, and the latter two cases are unlikely fatal bugs,
and promoting them to double faults would be fine.

This fixes a bug in which the espfix64 code mishandles a stack segment
violation.

This saves 4k of memory per CPU and a tiny bit of code.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There's nothing special enough about the espfix64 double fault fixup to
justify writing it in assembly.  Move it to C.

This also fixes a bug: if the double fault came from an IST stack, the
old asm code would return to a partially uninitialized stack frame.

Fixes: 3891a04aSigned-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull ARM SoC fixes from Olof Johansson:
 "A collection of fixes this week:

   - A set of clock fixes for shmobile platforms
   - A fix for tegra that moves serial port labels to be per board.
     We're choosing to merge this for 3.18 because the labels will start
     being parsed in 3.19, and without this change serial port numbers
     that used to be stable since the dawn of time will change numbers.
   - A few other DT tweaks for Tegra.
   - A fix for multi_v7_defconfig that makes it stop spewing cpufreq
     errors on Arndale (Exynos)"

* tag 'armsoc-for-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: multi_v7_defconfig: fix failure setting CPU voltage by enabling dependent I2C controller
  ARM: tegra: roth: Fix SD card VDD_IO regulator
  ARM: tegra: Remove eMMC vmmc property for roth/tn7
  ARM: dts: tegra: move serial aliases to per-board
  ARM: tegra: Add serial port labels to Tegra124 DT
  ARM: shmobile: kzm9g legacy: Set i2c clks_per_count to 2
  ARM: shmobile: r8a7740 dtsi: Correct IIC0 parent clock
  ARM: shmobile: r8a7790: Fix SD3CKCR address to device tree
  ARM: shmobile: r8a7740 legacy: Correct IIC0 parent clock
  ARM: shmobile: r8a7740 legacy: Add missing INTCA clock for irqpin module
  ARM: shmobile: r8a7790: Fix SD3CKCR address
  ARM: dts: sun6i: Re-parent ahb1_mux to pll6 as required by dma controller

Pull percpu fix from Tejun Heo:
 "This contains one patch to fix a race condition which can lead to
  percpu_ref using a percpu pointer which is corrupted with a set DEAD
  bit.  The bug was introduced while separating out the ATOMIC mode flag
  from the DEAD flag.  The fix is pretty straight forward.

  I just committed the patch to the percpu tree but am sending out the
  pull request early as I'll be on vacation for a week.  The patch
  should be fairly safe and while the latency will be higher I'll be
  checking emails"

* 'for-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu-ref: fix DEAD flag contamination of percpu pointer

Pull btrfs deadlock fix from Chris Mason:
 "This has a fix for a long standing deadlock that we've been trying to
  nail down for a while.  It ended up being a bad interaction with the
  fair reader/writer locks and the order btrfs reacquires locks in the
  btree"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: fix lockups from btrfs_clear_path_blocking

While decoupling ATOMIC and DEAD flags, f47ad457 ("percpu_ref:
decouple switching to percpu mode and reinit") updated
__ref_is_percpu() so that it only tests ATOMIC flag to determine
whether the ref is in percpu mode or not; however, while DEAD implies
ATOMIC, the two flags are set separately during percpu_ref_kill() and
if __ref_is_percpu() races percpu_ref_kill(), it may see DEAD w/o
ATOMIC.  Because __ref_is_percpu() returns @ref->percpu_count_ptr
value verbatim as the percpu pointer after testing ATOMIC, the pointer
may now be contaminated with the DEAD flag.

This can be fixed by clearing the flag bits before returning the
pointer which was the fix proposed by Shaohua; however, as DEAD
implies ATOMIC, we can just test for both flags at once and avoid the
explicit masking.

Update __ref_is_percpu() so that it tests that both ATOMIC and DEAD
are clear before returning @ref->percpu_count_ptr as the percpu
pointer.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-Reviewed-by: Shaohua Li <shli@kernel.org>
Link: http://lkml.kernel.org/r/995deb699f5b873c45d667df4add3b06f73c2c25.1416638887.git.shli@kernel.org
Fixes: f47ad457 ("percpu_ref: decouple switching to percpu mode and reinit")

Pull timer fix from Thomas Gleixner:
 "A single bugfix for an init order problem in the sun4i subarch
  clockevents code"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clockevent: sun4i: Fix race condition in the probe code

Pull vfs fixes from Al Viro:
 "Assorted fixes, most in overlayfs land"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ovl: ovl_dir_fsync() cleanup
  ovl: update MAINTAINERS
  ovl: pass dentry into ovl_dir_read_merged()
  ovl: use lockless_dereference() for upperdentry
  ovl: allow filenames with comma
  ovl: fix race in private xattr checks
  ovl: fix remove/copy-up race
  ovl: rename filesystem type to "overlay"
  isofs: avoid unused function warning
  vfs: fix reference leak in d_prune_aliases()

Pull networking fixes from David Miller:

 1) Fix BUG when decrypting empty packets in mac80211, from Ronald Wahl.

 2) nf_nat_range is not fully initialized and this is copied back to
    userspace, from Daniel Borkmann.

 3) Fix read past end of b uffer in netfilter ipset, also from Dan
    Carpenter.

 4) Signed integer overflow in ipv4 address mask creation helper
    inet_make_mask(), from Vincent BENAYOUN.

 5) VXLAN, be2net, mlx4_en, and qlcnic need ->ndo_gso_check() methods to
    properly describe the device's capabilities, from Joe Stringer.

 6) Fix memory leaks and checksum miscalculations in openvswitch, from
    Pravin B SHelar and Jesse Gross.

 7) FIB rules passes back ambiguous error code for unreachable routes,
    making behavior confusing for userspace.  Fix from Panu Matilainen.

 8) ieee802154fake_probe() doesn't release resources properly on error,
    from Alexey Khoroshilov.

 9) Fix skb_over_panic in add_grhead(), from Daniel Borkmann.

10) Fix access of stale slave pointers in bonding code, from Nikolay
    Aleksandrov.

11) Fix stack info leak in PPP pptp code, from Mathias Krause.

12) Cure locking bug in IPX stack, from Jiri Bohac.

13) Revert SKB fclone memory freeing optimization that is racey and can
    allow accesses to freed up memory, from Eric Dumazet.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (71 commits)
  tcp: Restore RFC5961-compliant behavior for SYN packets
  net: Revert "net: avoid one atomic operation in skb_clone()"
  virtio-net: validate features during probe
  cxgb4 : Fix DCB priority groups being returned in wrong order
  ipx: fix locking regression in ipx_sendmsg and ipx_recvmsg
  openvswitch: Don't validate IPv6 label masks.
  pptp: fix stack info leak in pptp_getname()
  brcmfmac: don't include linux/unaligned/access_ok.h
  cxgb4i : Don't block unload/cxgb4 unload when remote closes TCP connection
  ipv6: delete protocol and unregister rtnetlink when cleanup
  net/mlx4_en: Add VXLAN ndo calls to the PF net device ops too
  bonding: fix curr_active_slave/carrier with loadbalance arp monitoring
  mac80211: minstrel_ht: fix a crash in rate sorting
  vxlan: Inline vxlan_gso_check().
  can: m_can: update to support CAN FD features
  can: m_can: fix incorrect error messages
  can: m_can: add missing delay after setting CCCR_INIT bit
  can: m_can: fix not set can_dlc for remote frame
  can: m_can: fix possible sleep in napi poll
  can: m_can: add missing message RAM initialization
  ...

Pull drm fixes from Dave Airlie:
 "Just two radeon and two intel fixes: endian and regression fixes"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: fix endian swapping in vbios fetch for tdp table
  drm/radeon: disable native backlight control on pre-r6xx asics (v2)
  drm/i915: Kick fbdev before vgacon
  drm/i915: drop WaSetupGtModeTdRowDispatch:snb

Pull sound fixes from Takashi Iwai:
 "This batch ended up as a relatively high volume due to pending ASoC
  fixes.  But most of fixes there are trivial and/or device- specific
  fixes and quirks, so safe to apply.  The only (ASoC) core fixes are
  the DPCM race fix and the machine-driver matching fix for
  componentization"

* tag 'sound-3.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda - fix the mic mute led problem for Latitude E5550
  ALSA: hda - move DELL_WMI_MIC_MUTE_LED to the tail in the quirk chain
  ASoC: wm_adsp: Avoid attempt to free buffers that might still be in use
  ALSA: usb-audio: Set the Control Selector to SU_SELECTOR_CONTROL for UAC2
  ALSA: usb-audio: Add ctrl message delay quirk for Marantz/Denon devices
  ASoC: sgtl5000: Fix SMALL_POP bit definition
  ASoC: cs42l51: re-hook of_match_table pointer
  ASoC: rt5670: change dapm routes of PLL connection
  ASoC: rt5670: correct the incorrect default values
  ASoC: samsung: Add MODULE_DEVICE_TABLE for Snow
  ASoC: max98090: Correct pclk divisor settings
  ASoC: dpcm: Fix race between FE/BE updates and trigger
  ASoC: Fix snd_soc_find_dai() matching component by name
  ASoC: rsnd: remove unsupported PAUSE flag
  ASoC: fsi: remove unsupported PAUSE flag
  ASoC: rt5645: Mark RT5645_TDM_CTRL_3 as readable
  ASoC: rockchip-i2s: fix infinite loop in rockchip_snd_rxctrl
  ASoC: es8328-i2c: Fix i2c_device_id name field in es8328_id
  ASoC: fsl_asrc: Add reg_defaults for regmap to fix kernel dump

Pull ACPI power management fix from Rafael Wysocki:
 "This is just a one-liner fixing a regression introduced in 3.13 that
  broke system suspend on some Chromebooks.

  On those machines there are ACPI device objects for some I2C devices
  that can wake up the system from sleep states, but that is done via a
  platform-specific mechanism and the ACPI objects don't contain any
  wakeup-related information.  When we started to use ACPI power
  management with those devices (which happened during the 3.13 cycle),
  their configuration confused the ACPI PM layer that returned error
  codes from suspend callbacks for them causing system suspend to fail.

  However, the ACPI PM layer can safely ignore the wakeup setting from a
  device driver if the ACPI object corresponding to the device in
  question doesn't contain wakeup information in which case the driver
  itself is responsible for setting up the device for system wakeup"

* tag 'pm+acpi-3.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / PM: Ignore wakeup setting if the ACPI companion can't wake up

Pull devicetree fixes from Rob Herring:
 "DeviceTree fixes for 3.18:

   - two fixes for OF selftest code
   - fix for PowerPC address parsing to disable work-around except on
     old PowerMACs
   - fix a crash when earlycon is enabled, but no device is found
   - DT documentation fixes and missing vendor prefixes

  All but the doc updates are also for stable"

* tag 'devicetree-fixes-for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  of/selftest: Fix testing when /aliases is missing
  of/selftest: Fix off-by-one error in removal path
  documentation: pinctrl bindings: Fix trivial typo 'abitrary'
  devicetree: bindings: Add vendor prefix for Micron Technology, Inc.
  of: Add vendor prefix for Chips&Media, Inc.
  of/base: Fix PowerPC address parsing hack
  devicetree: vendor-prefixes.txt: fix whitespace
  of: Fix crash if an earlycon driver is not found
  of/irq: Drop obsolete 'interrupts' vs 'interrupts-extended' text
  of: Spelling s/stucture/structure/
  devicetree: bindings: add sandisk to the vendor prefixes

Pull PCI fixes from Bjorn Helgaas:
 "These are fixes for an issue with 64-bit PCI bus addresses on 32-bit
  PAE kernels, an APM X-Gene problem (it depended on a generic change we
  removed before merging), a fix for my hotplug device configuration
  changes, and a devicetree documentation update.

  Resource management:
    - Support 64-bit bridge windows if we have 64-bit dma_addr_t (Yinghai Lu)

  PCI device hotplug:
    - Apply _HPX Link Control settings to all devices with a link (Yinghai Lu)

  Generic host bridge driver:
    - Add DT binding for "linux,pci-domain" property (Lucas Stach)

  APM X-Gene:
    - Assign resources to bus before adding new devices (Duc Dang)"

* tag 'pci-v3.18-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Support 64-bit bridge windows if we have 64-bit dma_addr_t
  PCI: Apply _HPX Link Control settings to all devices with a link
  PCI: Add missing DT binding for "linux,pci-domain" property
  PCI: xgene: Assign resources to bus before adding new devices

Pull SCSI target fixes from Nicholas Bellinger:
 "Here are the target-pending fixes queued for v3.18-rc6.

  The highlights include:

   - target-core OOPs fix with tcm_qla2xxx + vxworks FC initiators +
     zero length SCSI commands having a transfer direction set.  (Roland
     + Craig Watson)

   - vhost-scsi OOPs fix to explicitly prevent WWPN endpoint configfs
     group removal while qemu still has an active reference.  (Paolo +
     nab)

   - ib_srpt fix for RDMA hardware with lower srp_sq_size limits.
     (Bart)

   - two ib_isert work-arounds for running on ocrdma hardware (Or + Sagi
     + Chris)

   - iscsi-target discovery portal typo + SPC-3 PR Preempt SA key
     matching fix (Steve)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  IB/isert: Adjust CQ size to HW limits
  target: return CONFLICT only when SA key unmatched
  iser-target: Handle DEVICE_REMOVAL event on network portal listener correctly
  ib_isert: Add max_send_sge=2 minimum for control PDU responses
  srp-target: Retry when QP creation fails with ENOMEM
  iscsi-target: return the correct port in SendTargets
  vhost-scsi: Take configfs group dependency during VHOST_SCSI_SET_ENDPOINT
  target: Don't call TFO->write_pending if data_length == 0

Pull dmaengine fixes from Vinod Koul:
 "We have couple of fixes for dmaengine queued up:
   - dma mempcy fix for dma configuration of sun6i by Maxime
   - pl330 fixes: First the fixing allocation for data buffers by Liviu
     and then Jon's fixe for fifo width and usage"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: Fix allocation size for PL330 data buffer depth.
  dmaengine: pl330: Limit MFIFO usage for memcpy to avoid exhausting entries
  dmaengine: pl330: Align DMA memcpy operations to MFIFO width
  dmaengine: sun6i: Fix memcpy operation

Pull MIPS fixes from Ralf Baechle:
 "More 3.18 fixes for MIPS:

   - backtraces were not quite working on on 64-bit kernels
   - loongson needs a different cache coherency setting
   - Loongson 3 is a MIPS64 R2 version but due to erratum we treat is an
     older architecture revision.
   - fix build errors due to undefined references to __node_distances
     for certain configurations.
   - fix instruction decodig in the jump label code.
   - for certain configurations copy_{from,to}_user destroy the content
     of $3 so that register needs to be marked as clobbed by the calling
     code.
   - Hardware Table Walker fixes.
   - fill the delay slot of the last instruction of memcpy otherwise
     whatever ends up there randomly might have undesirable effects.
   - ensure get_user/__get_user always zero the variable to be read even
     in case of an error"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: jump_label.c: Handle the microMIPS J instruction encoding
  MIPS: jump_label.c: Correct the span of the J instruction
  MIPS: Zero variable read by get_user / __get_user in case of an error.
  MIPS: lib: memcpy: Restore NOP on delay slot before returning to caller
  MIPS: tlb-r4k: Add missing HTW stop/start sequences
  MIPS: asm: uaccess: Add v1 register to clobber list on EVA
  MIPS: oprofile: Fix backtrace on 64-bit kernel
  MIPS: Loongson: Set Loongson-3's ISA level to MIPS64R1
  MIPS: Loongson: Fix the write-combine CCA value setting
  MIPS: IP27: Fix __node_distances undefined error
  MIPS: Loongson3: Fix __node_distances undefined error

Pull powerpc fix from Michael Ellerman:
 "One fix from Scott, he says:

  This patch fixes a crash (introduced in v3.18-rc1) in the FSL MSI driver
  when threaded IRQs are enabled"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
  powerpc/fsl_msi: mark the msi cascade handler IRQF_NO_THREAD