Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

... without bothering with copy_..._user()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Just have copy_page_{to,from}_iter() fall back to kmap_atomic +
copy_{to,from}_iter() + kunmap_atomic() in ITER_BVEC case.  As
the matter of fact, that's what we want to do for any iov_iter
kind that isn't blocking - e.g. ITER_KVEC will also go that way
once we recognize it on iov_iter.c primitives level
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

same as iterate_all_kinds, but iterator is moved to the position past
the last byte we'd handled.

iov_iter_advance() converted to it
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

iterate_all_kinds(iter, size, ident, step_iovec, step_bvec)
iterates through the ranges covered by iter (up to size bytes total),
repeating step_iovec or step_bvec for each of those.  ident is
declared in expansion of that thing, either as struct iovec or
struct bvec, and it contains the range we are currently looking
at.  step_bvec should be a void expression, step_iovec - a size_t
one, with non-zero meaning "stop here, that many bytes from this
range left".  In the end, the amount actually handled is stored
in size.

iov_iter_copy_from_user_atomic() and iov_iter_alignment() converted
to it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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

Pull x86 fixes from Thomas Gleixner:
 "Misc fixes:
   - gold linker build fix
   - noxsave command line parsing fix
   - bugfix for NX setup
   - microcode resume path bug fix
   - _TIF_NOHZ versus TIF_NOHZ bugfix as discussed in the mysterious
     lockup thread"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, syscall: Fix _TIF_NOHZ handling in syscall_trace_enter_phase1
  x86, kaslr: Handle Gold linker for finding bss/brk
  x86, mm: Set NX across entire PMD at boot
  x86, microcode: Update BSPs microcode on resume
  x86: Require exact match for 'noxsave' command line option

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: two NUMA fixes, two cputime fixes and an RCU/lockdep fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency
  sched/cputime: Fix cpu_timer_sample_group() double accounting
  sched/numa: Avoid selecting oneself as swap target
  sched/numa: Fix out of bounds read in sched_init_numa()
  sched: Remove lockdep check in sched_move_task()

Pull perf fixes from Ingo Molnar:
 "Misc fixes: two Intel uncore driver fixes, a CPU-hotplug fix and a
  build dependencies fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/uncore: Fix boot crash on SBOX PMU on Haswell-EP
  perf/x86/intel/uncore: Fix IRP uncore register offsets on Haswell EP
  perf: Fix corruption of sibling list with hotplug
  perf/x86: Fix embarrasing typo

Pull core fix from Ingo Molnar:
 "Fix GENMASK macro shift overflow"

Nobody seems to currently use GENMASK() to fill every single last bit
(which is what overflows) in-tree, and gcc would warn about it, so we
have that going for us.  But apparently there are pending changes that
want this.

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  bitops: Fix shift overflow in GENMASK macros

Commit c3ae62af ("tcp: should drop incoming frames without ACK
flag set") was created to mitigate a security vulnerability in which a
local attacker is able to inject data into locally-opened sockets by
using TCP protocol statistics in procfs to quickly find the correct
sequence number.

This broke the RFC5961 requirement to send a challenge ACK in response
to spurious RST packets, which was subsequently fixed by commit
7b514a88 ("tcp: accept RST without ACK flag").

Unfortunately, the RFC5961 requirement that spurious SYN packets be
handled in a similar manner remains broken.

RFC5961 section 4 states that:

   ... the handling of the SYN in the synchronized state SHOULD be
   performed as follows:

   1) If the SYN bit is set, irrespective of the sequence number, TCP
      MUST send an ACK (also referred to as challenge ACK) to the remote
      peer:

      <SEQ=SND.NXT><ACK=RCV.NXT><CTL=ACK>

      After sending the acknowledgment, TCP MUST drop the unacceptable
      segment and stop processing further.

   By sending an ACK, the remote peer is challenged to confirm the loss
   of the previous connection and the request to start a new connection.
   A legitimate peer, after restart, would not have a TCB in the
   synchronized state.  Thus, when the ACK arrives, the peer should send
   a RST segment back with the sequence number derived from the ACK
   field that caused the RST.

   This RST will confirm that the remote peer has indeed closed the
   previous connection.  Upon receipt of a valid RST, the local TCP
   endpoint MUST terminate its connection.  The local TCP endpoint
   should then rely on SYN retransmission from the remote end to
   re-establish the connection.

This patch lets SYN packets through the discard added in c3ae62af,
so that spurious SYN packets are properly dealt with as per the RFC.

The challenge ACK is sent unconditionally and is rate-limited, so the
original vulnerability is not reintroduced by this patch.
Signed-off-by: Calvin Owens <calvinowens@fb.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Not sure what I was thinking, but doing anything after
releasing a refcount is suicidal or/and embarrassing.

By the time we set skb->fclone to SKB_FCLONE_FREE, another cpu
could have released last reference and freed whole skb.

We potentially corrupt memory or trap if CONFIG_DEBUG_PAGEALLOC is set.
Reported-by: Chris Mason <clm@fb.com>
Fixes: ce1a4ea3 ("net: avoid one atomic operation in skb_clone()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>