The race is between lookup_get_idr_uobject and
uverbs_idr_remove_uobj -> uverbs_uobject_put.

We deliberately do not call sychronize_rcu after the idr_remove in
uverbs_idr_remove_uobj for performance reasons, instead we call
kfree_rcu() during uverbs_uobject_put.

However, this means we can obtain pointers to uobj's that have
already been released and must protect against krefing them
using kref_get_unless_zero.

==================================================================
BUG: KASAN: use-after-free in copy_ah_attr_from_uverbs.isra.2+0x860/0xa00
Read of size 4 at addr ffff88005fda1ac8 by task syz-executor2/441

CPU: 1 PID: 441 Comm: syz-executor2 Not tainted 4.15.0-rc2+ #56
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
Call Trace:
dump_stack+0x8d/0xd4
print_address_description+0x73/0x290
kasan_report+0x25c/0x370
? copy_ah_attr_from_uverbs.isra.2+0x860/0xa00
copy_ah_attr_from_uverbs.isra.2+0x860/0xa00
? uverbs_try_lock_object+0x68/0xc0
? modify_qp.isra.7+0xdc4/0x10e0
modify_qp.isra.7+0xdc4/0x10e0
ib_uverbs_modify_qp+0xfe/0x170
? ib_uverbs_query_qp+0x970/0x970
? __lock_acquire+0xa11/0x1da0
ib_uverbs_write+0x55a/0xad0
? ib_uverbs_query_qp+0x970/0x970
? ib_uverbs_query_qp+0x970/0x970
? ib_uverbs_open+0x760/0x760
? futex_wake+0x147/0x410
? sched_clock_cpu+0x18/0x180
? check_prev_add+0x1680/0x1680
? do_futex+0x3b6/0xa30
? sched_clock_cpu+0x18/0x180
__vfs_write+0xf7/0x5c0
? ib_uverbs_open+0x760/0x760
? kernel_read+0x110/0x110
? lock_acquire+0x370/0x370
? __fget+0x264/0x3b0
vfs_write+0x18a/0x460
SyS_write+0xc7/0x1a0
? SyS_read+0x1a0/0x1a0
? trace_hardirqs_on_thunk+0x1a/0x1c
entry_SYSCALL_64_fastpath+0x18/0x85
RIP: 0033:0x448e29
RSP: 002b:00007f443fee0c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f443fee16bc RCX: 0000000000448e29
RDX: 0000000000000078 RSI: 00000000209f8000 RDI: 0000000000000012
RBP: 000000000070bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000008e98 R14: 00000000006ebf38 R15: 0000000000000000

Allocated by task 1:
kmem_cache_alloc_trace+0x16c/0x2f0
mlx5_alloc_cmd_msg+0x12e/0x670
cmd_exec+0x419/0x1810
mlx5_cmd_exec+0x40/0x70
mlx5_core_mad_ifc+0x187/0x220
mlx5_MAD_IFC+0xd7/0x1b0
mlx5_query_mad_ifc_gids+0x1f3/0x650
mlx5_ib_query_gid+0xa4/0xc0
ib_query_gid+0x152/0x1a0
ib_query_port+0x21e/0x290
mlx5_port_immutable+0x30f/0x490
ib_register_device+0x5dd/0x1130
mlx5_ib_add+0x3e7/0x700
mlx5_add_device+0x124/0x510
mlx5_register_interface+0x11f/0x1c0
mlx5_ib_init+0x56/0x61
do_one_initcall+0xa3/0x250
kernel_init_freeable+0x309/0x3b8
kernel_init+0x14/0x180
ret_from_fork+0x24/0x30

Freed by task 1:
kfree+0xeb/0x2f0
mlx5_free_cmd_msg+0xcd/0x140
cmd_exec+0xeba/0x1810
mlx5_cmd_exec+0x40/0x70
mlx5_core_mad_ifc+0x187/0x220
mlx5_MAD_IFC+0xd7/0x1b0
mlx5_query_mad_ifc_gids+0x1f3/0x650
mlx5_ib_query_gid+0xa4/0xc0
ib_query_gid+0x152/0x1a0
ib_query_port+0x21e/0x290
mlx5_port_immutable+0x30f/0x490
ib_register_device+0x5dd/0x1130
mlx5_ib_add+0x3e7/0x700
mlx5_add_device+0x124/0x510
mlx5_register_interface+0x11f/0x1c0
mlx5_ib_init+0x56/0x61
do_one_initcall+0xa3/0x250
kernel_init_freeable+0x309/0x3b8
kernel_init+0x14/0x180
ret_from_fork+0x24/0x30

The buggy address belongs to the object at ffff88005fda1ab0
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes inside of
32-byte region [ffff88005fda1ab0, ffff88005fda1ad0)
The buggy address belongs to the page:
page:00000000d5655c19 count:1 mapcount:0 mapping: (null)
index:0xffff88005fda1fc0
flags: 0x4000000000000100(slab)
raw: 4000000000000100 0000000000000000 ffff88005fda1fc0 0000000180550008
raw: ffffea00017f6780 0000000400000004 ffff88006c803980 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88005fda1980: fc fc fb fb fb fb fc fc fb fb fb fb fc fc fb fb
ffff88005fda1a00: fb fb fc fc fb fb fb fb fc fc 00 00 00 00 fc fc
ffff88005fda1a80: fb fb fb fb fc fc fb fb fb fb fc fc fb fb fb fb
ffff88005fda1b00: fc fc 00 00 00 00 fc fc fb fb fb fb fc fc fb fb
ffff88005fda1b80: fb fb fc fc fb fb fb fb fc fc fb fb fb fb fc fc
==================================================================@

Cc: syzkaller <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org> # 4.11
Fixes: 38321256 ("IB/core: Add support for idr types")
Reported-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

This clarifies the design intention that time between allocate and
commit has the uobj exclusive to the caller. We already guarantee
this by delaying publishing the uobj pointer via idr_insert,
fd_install, list_add, etc.

Additionally holding the usecnt lock during this period provides
extra clarity and more protection against future mistakes.

Fixes: 38321256 ("IB/core: Add support for idr types")
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

If the same attribute is listed twice by the user in the ioctl attribute
list then error unwind can cause the kernel to deref garbage.

This happens when an object with WRITE access is sent twice. The second
parse properly fails but corrupts the state required for the error unwind
it triggers.

Fixing this by making duplicates in the attribute list invalid. This is
not something we need to support.

The ioctl interface is currently recommended to be disabled in kConfig.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

32 bit processes running on a 64 bit kernel call compat_ioctl so that
implementations can revise any structure layout issues. Point compat_ioctl
at our normal ioctl because:

- All our structures are designed to be the same on 32 and 64 bit, ie we
  use __aligned_u64 when required and are careful to manage padding.

- Any pointers are stored in u64's and userspace is expected
  to prepare them properly.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

This has no impact on the structure layout since these structs already
have their u64s already properly aligned, but it does document that we
have this requirement for 32 bit compatibility.
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

Fix a bug in uverbs_ioctl_merge that looked at the object's iterator
number instead of the method's iterator number when merging methods.

While we're at it, make the uverbs_ioctl_merge code a bit more clear
and faster.

Fixes: 118620d3 ('IB/core: Add uverbs merge trees functionality')
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

The union approach will get the endianness wrong sometimes if the kernel's
pointer size is 32 bits resulting in EFAULTs when trying to copy to/from
user.
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

The rule for the API is pointers less than 8 bytes are inlined into
the .data field of the attribute. Fix the creation of the driver udata
struct to follow this rule and point to the .data itself when the size
is less than 8 bytes.

Otherwise if the UHW struct is less than 8 bytes the driver will get
EFAULT during copy_from_user.
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

This fixes several bugs around the copy_to/from user path:
 - copy_to used the user provided size of the attribute
   and could copy data beyond the end of the kernel buffer into
   userspace.
 - copy_from didn't know the size of the kernel buffer and
   could have left kernel memory unexpectedly un-initialized.
 - copy_from did not use the user length to determine if the
   attribute data is inlined or not.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

Resource tracking of XRCD objects is not implemented in current
version of restrack and hence can be removed.

Fixes: 02d8883f ("RDMA/restrack: Add general infrastructure to track RDMA resources")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

netdev_wait_allrefs() could rebroadcast NETDEV_UNREGISTER event
multiple times until all refs are gone, which will result in calling
ipoib_delete_debug_files multiple times and printing a warning.

Remove the WARN_ONCE since checks of NULL pointers before calling
debugfs_remove are not needed.

Fixes: 771a5258 ("IB/IPoIB: ibX: failed to create mcg debug file")
Signed-off-by: Alaa Hleihel <alaa@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

except, again, POLLFREE and POLL_BUSY_LOOP.

With this, we finally get to the promised end result:

 - POLL{IN,OUT,...} are plain integers and *not* in __poll_t, so any
   stray instances of ->poll() still using those will be caught by
   sparse.

 - eventpoll.c and select.c warning-free wrt __poll_t

 - no more kernel-side definitions of POLL... - userland ones are
   visible through the entire kernel (and used pretty much only for
   mangle/demangle)

 - same behavior as after the first series (i.e. sparc et.al. epoll(2)
   working correctly).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull more poll annotation updates from Al Viro:
 "This is preparation to solving the problems you've mentioned in the
  original poll series.

  After this series, the kernel is ready for running

      for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
            L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
            for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
      done

  as a for bulk search-and-replace.

  After that, the kernel is ready to apply the patch to unify
  {de,}mangle_poll(), and then get rid of kernel-side POLL... uses
  entirely, and we should be all done with that stuff.

  Basically, that's what you suggested wrt KPOLL..., except that we can
  use EPOLL... instead - they already are arch-independent (and equal to
  what is currently kernel-side POLL...).

  After the preparations (in this series) switch to returning EPOLL...
  from ->poll() instances is completely mechanical and kernel-side
  POLL... can go away. The last step (killing kernel-side POLL... and
  unifying {de,}mangle_poll() has to be done after the
  search-and-replace job, since we need userland-side POLL... for
  unified {de,}mangle_poll(), thus the cherry-pick at the last step.

  After that we will have:

   - POLL{IN,OUT,...} *not* in __poll_t, so any stray instances of
     ->poll() still using those will be caught by sparse.

   - eventpoll.c and select.c warning-free wrt __poll_t

   - no more kernel-side definitions of POLL... - userland ones are
     visible through the entire kernel (and used pretty much only for
     mangle/demangle)

   - same behavior as after the first series (i.e. sparc et.al. epoll(2)
     working correctly)"

* 'work.poll2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  annotate ep_scan_ready_list()
  ep_send_events_proc(): return result via esed->res
  preparation to switching ->poll() to returning EPOLL...
  add EPOLLNVAL, annotate EPOLL... and event_poll->event
  use linux/poll.h instead of asm/poll.h
  xen: fix poll misannotation
  smc: missing poll annotations

Pull xtense fix from Max Filippov:
 "Build fix for xtensa architecture with KASAN enabled"

* tag 'xtensa-20180211' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: fix build with KASAN

Pull nios2 update from Ley Foon Tan:

 - clean up old Kconfig options from defconfig

 - remove leading 0x and 0s from bindings notation in dts files

* tag 'nios2-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2:
  nios2: defconfig: Cleanup from old Kconfig options
  nios2: dts: Remove leading 0x and 0s from bindings notation

The commit 917538e2 ("kasan: clean up KASAN_SHADOW_SCALE_SHIFT
usage") removed KASAN_SHADOW_SCALE_SHIFT definition from
include/linux/kasan.h and added it to architecture-specific headers,
except for xtensa. This broke the xtensa build with KASAN enabled.
Define KASAN_SHADOW_SCALE_SHIFT in arch/xtensa/include/asm/kasan.h

Reported by: kbuild test robot <fengguang.wu@intel.com>
Fixes: 917538e2 ("kasan: clean up KASAN_SHADOW_SCALE_SHIFT usage")
Acked-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Remove old, dead Kconfig option INET_LRO. It is gone since
commit 7bbf3cae ("ipv4: Remove inet_lro library").
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>

Improve the DTS files by removing all the leading "0x" and zeros to fix the
following dtc warnings:

Warning (unit_address_format): Node /XXX unit name should not have leading "0x"

and

Warning (unit_address_format): Node /XXX unit name should not have leading 0s

Converted using the following command:

find . -type f \( -iname *.dts -o -iname *.dtsi \) -exec sed -E -i -e "s/@0x([0-9a-fA-F\.]+)\s?\{/@\L\1 \{/g" -e "s/@0+([0-9a-fA-F\.]+)\s?\{/@\L\1 \{/g" {} +

For simplicity, two sed expressions were used to solve each warnings separately.

To make the regex expression more robust a few other issues were resolved,
namely setting unit-address to lower case, and adding a whitespace before the
the opening curly brace:

https://elinux.org/Device_Tree_Linux#Linux_conventions

This is a follow up to commit 4c9847b7 ("dt-bindings: Remove leading 0x from bindings notation")
Reported-by: David Daney <ddaney@caviumnetworks.com>
Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>

Pull PCI fix from Bjorn Helgaas:
 "Fix a POWER9/powernv INTx regression from the merge window (Alexey
  Kardashevskiy)"

* tag 'pci-v4.16-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  powerpc/pci: Fix broken INTx configuration via OF

Pull block fixes from Jens Axboe:
 "A few fixes to round off the merge window on the block side:

   - a set of bcache fixes by way of Michael Lyle, from the usual bcache
     suspects.

   - add a simple-to-hook-into function for bpf EIO error injection.

   - fix blk-wbt that mischarectized flushes as reads. Improve the logic
     so that flushes and writes are accounted as writes, and only reads
     as reads. From me.

   - fix requeue crash in BFQ, from Paolo"

* tag 'for-linus-20180210' of git://git.kernel.dk/linux-block:
  block, bfq: add requeue-request hook
  bcache: fix for data collapse after re-attaching an attached device
  bcache: return attach error when no cache set exist
  bcache: set writeback_rate_update_seconds in range [1, 60] seconds
  bcache: fix for allocator and register thread race
  bcache: set error_limit correctly
  bcache: properly set task state in bch_writeback_thread()
  bcache: fix high CPU occupancy during journal
  bcache: add journal statistic
  block: Add should_fail_bio() for bpf error injection
  blk-wbt: account flush requests correctly

Pull x86 platform driver updates from Darren Hart:
 "Mellanox fixes and new system type support.

  Mostly data for new system types with a correction and an
  uninitialized variable fix"

[ Pulling from github because git.infradead.org currently seems to be
  down for some reason, but Darren had a backup location    - Linus ]

* tag 'platform-drivers-x86-v4.16-3' of git://github.com/dvhart/linux-pdx86:
  platform/x86: mlx-platform: Add support for new 200G IB and Ethernet systems
  platform/x86: mlx-platform: Add support for new msn201x system type
  platform/x86: mlx-platform: Add support for new msn274x system type
  platform/x86: mlx-platform: Fix power cable setting for msn21xx family
  platform/x86: mlx-platform: Add define for the negative bus
  platform/x86: mlx-platform: Use defines for bus assignment
  platform/mellanox: mlxreg-hotplug: Fix uninitialized variable

Merge tag 'chrome-platform-for-linus-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bleung/chrome-platform

Pull chrome platform updates from Benson Leung:

 - move cros_ec_dev to drivers/mfd

 - other small maintenance fixes

[ The cros_ec_dev movement came in earlier through the MFD tree  - Linus ]

* tag 'chrome-platform-for-linus-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bleung/chrome-platform:
  platform/chrome: Use proper protocol transfer function
  platform/chrome: cros_ec_lpc: Add support for Google Glimmer
  platform/chrome: cros_ec_lpc: Register the driver if ACPI entry is missing.
  platform/chrome: cros_ec_lpc: remove redundant pointer request
  cros_ec: fix nul-termination for firmware build info
  platform/chrome: chromeos_laptop: make chromeos_laptop const

Pull KVM updates from Radim Krčmář:
 "ARM:

   - icache invalidation optimizations, improving VM startup time

   - support for forwarded level-triggered interrupts, improving
     performance for timers and passthrough platform devices

   - a small fix for power-management notifiers, and some cosmetic
     changes

  PPC:

   - add MMIO emulation for vector loads and stores

   - allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without
     requiring the complex thread synchronization of older CPU versions

   - improve the handling of escalation interrupts with the XIVE
     interrupt controller

   - support decrement register migration

   - various cleanups and bugfixes.

  s390:

   - Cornelia Huck passed maintainership to Janosch Frank

   - exitless interrupts for emulated devices

   - cleanup of cpuflag handling

   - kvm_stat counter improvements

   - VSIE improvements

   - mm cleanup

  x86:

   - hypervisor part of SEV

   - UMIP, RDPID, and MSR_SMI_COUNT emulation

   - paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit

   - allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more
     AVX512 features

   - show vcpu id in its anonymous inode name

   - many fixes and cleanups

   - per-VCPU MSR bitmaps (already merged through x86/pti branch)

   - stable KVM clock when nesting on Hyper-V (merged through
     x86/hyperv)"

* tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (197 commits)
  KVM: PPC: Book3S: Add MMIO emulation for VMX instructions
  KVM: PPC: Book3S HV: Branch inside feature section
  KVM: PPC: Book3S HV: Make HPT resizing work on POWER9
  KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code
  KVM: PPC: Book3S PR: Fix broken select due to misspelling
  KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
  KVM: PPC: Book3S PR: Fix svcpu copying with preemption enabled
  KVM: PPC: Book3S HV: Drop locks before reading guest memory
  kvm: x86: remove efer_reload entry in kvm_vcpu_stat
  KVM: x86: AMD Processor Topology Information
  x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested
  kvm: embed vcpu id to dentry of vcpu anon inode
  kvm: Map PFN-type memory regions as writable (if possible)
  x86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n
  KVM: arm/arm64: Fixup userspace irqchip static key optimization
  KVM: arm/arm64: Fix userspace_irqchip_in_use counting
  KVM: arm/arm64: Fix incorrect timer_is_pending logic
  MAINTAINERS: update KVM/s390 maintainers
  MAINTAINERS: add Halil as additional vfio-ccw maintainer
  MAINTAINERS: add David as a reviewer for KVM/s390
  ...

59f47eff ("powerpc/pci: Use of_irq_parse_and_map_pci() helper")
replaced of_irq_parse_pci() + irq_create_of_mapping() with
of_irq_parse_and_map_pci(), but neglected to capture the virq
returned by irq_create_of_mapping(), so virq remained zero, which
caused INTx configuration to fail.

Save the virq value returned by of_irq_parse_and_map_pci() and correct
the virq declaration to match the of_irq_parse_and_map_pci() signature.

Fixes: 59f47eff "powerpc/pci: Use of_irq_parse_and_map_pci() helper"
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Pull more Kbuild updates from Masahiro Yamada:
 "Makefile changes:
   - enable unused-variable warning that was wrongly disabled for clang

  Kconfig changes:
   - warn about blank 'help' and fix existing instances
   - fix 'choice' behavior to not write out invisible symbols
   - fix misc weirdness

  Coccinell changes:
   - fix false positive of free after managed memory alloc detection
   - improve performance of NULL dereference detection"

* tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
  kconfig: remove const qualifier from sym_expand_string_value()
  kconfig: add xrealloc() helper
  kconfig: send error messages to stderr
  kconfig: echo stdin to stdout if either is redirected
  kconfig: remove check_stdin()
  kconfig: remove 'config*' pattern from .gitignnore
  kconfig: show '?' prompt even if no help text is available
  kconfig: do not write choice values when their dependency becomes n
  coccinelle: deref_null: avoid useless computation
  coccinelle: devm_free: reduce false positives
  kbuild: clang: disable unused variable warnings only when constant
  kconfig: Warn if help text is blank
  nios2: kconfig: Remove blank help text
  arm: vt8500: kconfig: Remove blank help text
  MIPS: kconfig: Remove blank help text
  MIPS: BCM63XX: kconfig: Remove blank help text
  lib/Kconfig.debug: Remove blank help text
  Staging: rtl8192e: kconfig: Remove blank help text
  Staging: rtl8192u: kconfig: Remove blank help text
  mmc: kconfig: Remove blank help text
  ...

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

Pull misc vfs fixes from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  seq_file: fix incomplete reset on read from zero offset
  kernfs: fix regression in kernfs_fop_write caused by wrong type

This function returns realloc'ed memory, so the returned pointer
must be passed to free() when done.  So, 'const' qualifier is odd.
It is allowed to modify the expanded string.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

We already have xmalloc(), xcalloc().  Add xrealloc() as well
to save tedious error handling.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

It adds support for new Mellanox system types of basic classes qmb7, sn34,
sn37, containing systems QMB700 (40x200GbE InfiniBand switch), SN3700
(32x200GbE and 16x400GbE Ethernet switch) and SN3410 (6x400GbE plus
48x50GbE Ethernet switch). These are the Top of the Rack systems, equipped
with Mellanox COM-Express carrier board and switch board with Mellanox
Quantum device, which supports InfiniBand switching with 40X200G ports and
line rate of up to HDR speed or with Mellanox Spectrum-2 device, which
supports Ethernet switching with 32X200G ports line rate of up to HDR
speed.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

It adds support for new Mellanox system types of basic half unit size
class msn201x, containing system MSN2010 (18x10GbE plus 4x4x25GbE) half
and its derivatives. This is the Top of the Rack system, equipped with
Mellanox Small Form Factor carrier board and switch board with Mellanox
Spectrum device, which supports Ethernet switching with 32X100G ports line
rate of up to EDR speed.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

It adds support for new Mellanox system types of basic class msn274x,
containing system MSN2740 (32x100GbE Ethernet switch with cost reduction)
and its derivatives. These are the Top of the Rack system, equipped with
Mellanox Small Form Factor carrier board and switch board with Mellanox
Spectrum device, which supports Ethernet switching with 32X100G ports line
rate of up to EDR speed.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

Pull networking fixes from David Miller:

 1) Make allocations less aggressive in x_tables, from Minchal Hocko.

 2) Fix netfilter flowtable Kconfig deps, from Pablo Neira Ayuso.

 3) Fix connection loss problems in rtlwifi, from Larry Finger.

 4) Correct DRAM dump length for some chips in ath10k driver, from Yu
    Wang.

 5) Fix ABORT handling in rxrpc, from David Howells.

 6) Add SPDX tags to Sun networking drivers, from Shannon Nelson.

 7) Some ipv6 onlink handling fixes, from David Ahern.

 8) Netem packet scheduler interval calcualtion fix from Md. Islam.

 9) Don't put crypto buffers on-stack in rxrpc, from David Howells.

10) Fix handling of error non-delivery status in netlink multicast
    delivery over multiple namespaces, from Nicolas Dichtel.

11) Missing xdp flush in tuntap driver, from Jason Wang.

12) Synchonize RDS protocol netns/module teardown with rds object
    management, from Sowini Varadhan.

13) Add nospec annotations to mpls, from Dan Williams.

14) Fix SKB truesize handling in TIPC, from Hoang Le.

15) Interrupt masking fixes in stammc from Niklas Cassel.

16) Don't allow ptr_ring objects to be sized outside of kmalloc's
    limits, from Jason Wang.

17) Don't allow SCTP chunks to be built which will have a length
    exceeding the chunk header's 16-bit length field, from Alexey
    Kodanev.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (82 commits)
  ibmvnic: Remove skb->protocol checks in ibmvnic_xmit
  bpf: fix rlimit in reuseport net selftest
  sctp: verify size of a new chunk in _sctp_make_chunk()
  s390/qeth: fix SETIP command handling
  s390/qeth: fix underestimated count of buffer elements
  ptr_ring: try vmalloc() when kmalloc() fails
  ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
  net: stmmac: remove redundant enable of PMT irq
  net: stmmac: rename GMAC_INT_DEFAULT_MASK for dwmac4
  net: stmmac: discard disabled flags in interrupt status register
  ibmvnic: Reset long term map ID counter
  tools/libbpf: handle issues with bpf ELF objects containing .eh_frames
  selftests/bpf: add selftest that use test_libbpf_open
  selftests/bpf: add test program for loading BPF ELF files
  tools/libbpf: improve the pr_debug statements to contain section numbers
  bpf: Sync kernel ABI header with tooling header for bpf_common.h
  net: phy: fix phy_start to consider PHY_IGNORE_INTERRUPT
  net: thunder: change q_len's type to handle max ring size
  tipc: fix skb truesize/datasize ratio control
  net/sched: cls_u32: fix cls_u32 on filter replace
  ...

Pull more NFS client updates from Trond Myklebust:
 "A few bugfixes and some small sunrpc latency/performance improvements
  before the merge window closes:

  Stable fixes:

   - fix an incorrect calculation of the RDMA send scatter gather
     element limit

   - fix an Oops when attempting to free resources after RDMA device
     removal

  Bugfixes:

   - SUNRPC: Ensure we always release the TCP socket in a timely fashion
     when the connection is shut down.

   - SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context

  Latency/Performance:

   - SUNRPC: Queue latency sensitive socket tasks to the less contended
     xprtiod queue

   - SUNRPC: Make the xprtiod workqueue unbounded.

   - SUNRPC: Make the rpciod workqueue unbounded"

* tag 'nfs-for-4.16-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context
  fix parallelism for rpc tasks
  Make the xprtiod workqueue unbounded.
  SUNRPC: Queue latency-sensitive socket tasks to xprtiod
  SUNRPC: Ensure we always close the socket after a connection shuts down
  xprtrdma: Fix BUG after a device removal
  xprtrdma: Fix calculation of ri_max_send_sges

Pull SCSI target updates from Nicholas Bellinger:
 "The highlights include:

   - numerous target-core-user improvements related to queue full and
     timeout handling. (MNC)

   - prevent target-core-user corruption when invalid data page is
     requested. (MNC)

   - add target-core device action configfs attributes to allow
     user-space to trigger events separate from existing attributes
     exposed to end-users. (MNC)

   - fix iscsi-target NULL pointer dereference 4.6+ regression in CHAP
     error path. (David Disseldorp)

   - avoid target-core backend UNMAP callbacks if range is zero. (Andrei
     Vagin)

   - fix a iscsi-target 4.14+ regression related multiple PDU logins,
     that was exposed due to removal of TCP prequeue support. (Florian
     Westphal + MNC)

  Also, there is a iser-target bug still being worked on for post -rc1
  code to address a long standing issue resulting in persistent
  ib_post_send() failures, for RNICs with small max_send_sge"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (36 commits)
  iscsi-target: make sure to wake up sleeping login worker
  tcmu: Fix trailing semicolon
  tcmu: fix cmd user after free
  target: fix destroy device in target_configure_device
  tcmu: allow userspace to reset ring
  target core: add device action configfs files
  tcmu: fix error return code in tcmu_configure_device()
  target_core_user: add cmd id to broken ring message
  target: add SAM_STAT_BUSY sense reason
  tcmu: prevent corruption when invalid data page requested
  target: don't call an unmap callback if a range length is zero
  target/iscsi: avoid NULL dereference in CHAP auth error path
  cxgbit: call neigh_event_send() to update MAC address
  target: tcm_loop: Use seq_puts() in tcm_loop_show_info()
  target: tcm_loop: Delete an unnecessary return statement in tcm_loop_submission_work()
  target: tcm_loop: Delete two unnecessary variable initialisations in tcm_loop_issue_tmr()
  target: tcm_loop: Combine substrings for 26 messages
  target: tcm_loop: Improve a size determination in two functions
  target: tcm_loop: Delete an error message for a failed memory allocation in four functions
  sbp-target: Delete an error message for a failed memory allocation in three functions
  ...

Pull tracing fixes from Steven Rostedt:
 "Al Viro discovered some breakage with the parsing of the
  set_ftrace_filter as well as the removing of function probes.

  This fixes the code with Al's suggestions. I also added a few
  selftests to test the broken cases such that they wont happen
  again"

* tag 'trace-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  selftests/ftrace: Add more tests for removing of function probes
  selftests/ftrace: Add some missing glob checks
  selftests/ftrace: Have reset_ftrace_filter handle multiple instances
  selftests/ftrace: Have reset_ftrace_filter handle modules
  tracing: Fix parsing of globs with a wildcard at the beginning
  ftrace: Remove incorrect setting of glob search field

Pull cifs fixes from Steve French:
 "There are a couple additional security fixes that are still being
  tested that are not in this set."

* tag '4.16-minor-rc-SMB3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  Add missing structs and defines from recent SMB3.1.1 documentation
  address lock imbalance warnings in smbdirect.c
  cifs: silence compiler warnings showing up with gcc-8.0.0
  Add some missing debug fields in server and tcon structs

Pull fbdev fix from Bartlomiej Zolnierkiewicz:
 "Fix building of the omapfb driver (Tomi Valkeinen)"

* tag 'fbdev-v4.16-fix' of git://github.com/bzolnier/linux:
  video: omapfb: fix missing #includes