Fix a race in the multi-order iteration code which causes the kernel to
hit a GP fault.  This was first seen with a production v4.15 based
kernel (4.15.6-300.fc27.x86_64) utilizing a DAX workload which used
order 9 PMD DAX entries.

The race has to do with how we tear down multi-order sibling entries
when we are removing an item from the tree.  Remember for example that
an order 2 entry looks like this:

  struct radix_tree_node.slots[] = [entry][sibling][sibling][sibling]

where 'entry' is in some slot in the struct radix_tree_node, and the
three slots following 'entry' contain sibling pointers which point back
to 'entry.'

When we delete 'entry' from the tree, we call :

  radix_tree_delete()
    radix_tree_delete_item()
      __radix_tree_delete()
        replace_slot()

replace_slot() first removes the siblings in order from the first to the
last, then at then replaces 'entry' with NULL.  This means that for a
brief period of time we end up with one or more of the siblings removed,
so:

  struct radix_tree_node.slots[] = [entry][NULL][sibling][sibling]

This causes an issue if you have a reader iterating over the slots in
the tree via radix_tree_for_each_slot() while only under
rcu_read_lock()/rcu_read_unlock() protection.  This is a common case in
mm/filemap.c.

The issue is that when __radix_tree_next_slot() => skip_siblings() tries
to skip over the sibling entries in the slots, it currently does so with
an exact match on the slot directly preceding our current slot.
Normally this works:

                                      V preceding slot
  struct radix_tree_node.slots[] = [entry][sibling][sibling][sibling]
                                              ^ current slot

This lets you find the first sibling, and you skip them all in order.

But in the case where one of the siblings is NULL, that slot is skipped
and then our sibling detection is interrupted:

                                             V preceding slot
  struct radix_tree_node.slots[] = [entry][NULL][sibling][sibling]
                                                    ^ current slot

This means that the sibling pointers aren't recognized since they point
all the way back to 'entry', so we think that they are normal internal
radix tree pointers.  This causes us to think we need to walk down to a
struct radix_tree_node starting at the address of 'entry'.

In a real running kernel this will crash the thread with a GP fault when
you try and dereference the slots in your broken node starting at
'entry'.

We fix this race by fixing the way that skip_siblings() detects sibling
nodes.  Instead of testing against the preceding slot we instead look
for siblings via is_sibling_entry() which compares against the position
of the struct radix_tree_node.slots[] array.  This ensures that sibling
entries are properly identified, even if they are no longer contiguous
with the 'entry' they point to.

Link: http://lkml.kernel.org/r/20180503192430.7582-6-ross.zwisler@linux.intel.com
Fixes: 148deab2 ("radix-tree: improve multiorder iterators")
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reported-by: CR, Sapthagirish <sapthagirish.cr@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add a test which shows a race in the multi-order iteration code.  This
test reliably hits the race in under a second on my machine, and is the
result of a real bug report against kernel a production v4.15 based
kernel (4.15.6-300.fc27.x86_64).  With a real kernel this issue is hit
when using order 9 PMD DAX radix tree entries.

The race has to do with how we tear down multi-order sibling entries
when we are removing an item from the tree.  Remember that an order 2
entry looks like this:

  struct radix_tree_node.slots[] = [entry][sibling][sibling][sibling]

where 'entry' is in some slot in the struct radix_tree_node, and the
three slots following 'entry' contain sibling pointers which point back
to 'entry.'

When we delete 'entry' from the tree, we call :

  radix_tree_delete()
    radix_tree_delete_item()
      __radix_tree_delete()
        replace_slot()

replace_slot() first removes the siblings in order from the first to the
last, then at then replaces 'entry' with NULL.  This means that for a
brief period of time we end up with one or more of the siblings removed,
so:

  struct radix_tree_node.slots[] = [entry][NULL][sibling][sibling]

This causes an issue if you have a reader iterating over the slots in
the tree via radix_tree_for_each_slot() while only under
rcu_read_lock()/rcu_read_unlock() protection.  This is a common case in
mm/filemap.c.

The issue is that when __radix_tree_next_slot() => skip_siblings() tries
to skip over the sibling entries in the slots, it currently does so with
an exact match on the slot directly preceding our current slot.
Normally this works:

                                      V preceding slot
  struct radix_tree_node.slots[] = [entry][sibling][sibling][sibling]
                                              ^ current slot

This lets you find the first sibling, and you skip them all in order.

But in the case where one of the siblings is NULL, that slot is skipped
and then our sibling detection is interrupted:

                                             V preceding slot
  struct radix_tree_node.slots[] = [entry][NULL][sibling][sibling]
                                                    ^ current slot

This means that the sibling pointers aren't recognized since they point
all the way back to 'entry', so we think that they are normal internal
radix tree pointers.  This causes us to think we need to walk down to a
struct radix_tree_node starting at the address of 'entry'.

In a real running kernel this will crash the thread with a GP fault when
you try and dereference the slots in your broken node starting at
'entry'.

In the radix tree test suite this will be caught by the address
sanitizer:

  ==27063==ERROR: AddressSanitizer: heap-buffer-overflow on address
  0x60c0008ae400 at pc 0x00000040ce4f bp 0x7fa89b8fcad0 sp 0x7fa89b8fcac0
  READ of size 8 at 0x60c0008ae400 thread T3
      #0 0x40ce4e in __radix_tree_next_slot /home/rzwisler/project/linux/tools/testing/radix-tree/radix-tree.c:1660
      #1 0x4022cc in radix_tree_next_slot linux/../../../../include/linux/radix-tree.h:567
      #2 0x4022cc in iterator_func /home/rzwisler/project/linux/tools/testing/radix-tree/multiorder.c:655
      #3 0x7fa8a088d50a in start_thread (/lib64/libpthread.so.0+0x750a)
      #4 0x7fa8a03bd16e in clone (/lib64/libc.so.6+0xf516e)

Link: http://lkml.kernel.org/r/20180503192430.7582-5-ross.zwisler@linux.intel.comSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: CR, Sapthagirish <sapthagirish.cr@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently the lifetime of "struct item" entries in the radix tree are
not controlled by RCU, but are instead deleted inline as they are
removed from the tree.

In the following patches we add a test which has threads iterating over
items pulled from the tree and verifying them in an
rcu_read_lock()/rcu_read_unlock() section.  This means that though an
item has been removed from the tree it could still be being worked on by
other threads until the RCU grace period expires.  So, we need to
actually free the "struct item" structures at the end of the grace
period, just as we do with "struct radix_tree_node" items.

Link: http://lkml.kernel.org/r/20180503192430.7582-4-ross.zwisler@linux.intel.comSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: CR, Sapthagirish <sapthagirish.cr@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pulled from a patch from Matthew Wilcox entitled "xarray: Add definition
of struct xarray":

> From: Matthew Wilcox <mawilcox@microsoft.com>
> Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>

  https://patchwork.kernel.org/patch/10341249/

These defines fix this compilation error:

  In file included from ./linux/radix-tree.h:6:0,
                   from ./linux/../../../../include/linux/idr.h:15,
                   from ./linux/idr.h:1,
                   from idr.c:4:
  ./linux/../../../../include/linux/idr.h: In function `idr_init_base':
  ./linux/../../../../include/linux/radix-tree.h:129:2: warning: implicit declaration of function `spin_lock_init'; did you mean `spinlock_t'? [-Wimplicit-function-declaration]
    spin_lock_init(&(root)->xa_lock);    \
    ^
  ./linux/../../../../include/linux/idr.h:126:2: note: in expansion of macro `INIT_RADIX_TREE'
    INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);
    ^~~~~~~~~~~~~~~

by providing a spin_lock_init() wrapper for the v4.17-rc* version of the
radix tree test suite.

Link: http://lkml.kernel.org/r/20180503192430.7582-3-ross.zwisler@linux.intel.comSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: CR, Sapthagirish <sapthagirish.cr@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit c6ce3e2f ("radix tree test suite: Add config option for map
shift") introduced a phony makefile target called 'mapshift' that ends
up generating the file generated/map-shift.h.  This phony target was
then added as a dependency of the top level 'targets' build target,
which is what is run when you go to tools/testing/radix-tree and just
type 'make'.

Unfortunately, this phony target doesn't actually work as a dependency,
so you end up getting:

  $ make
  make: *** No rule to make target 'generated/map-shift.h', needed by 'main.o'.  Stop.
  make: *** Waiting for unfinished jobs....

Fix this by making the file generated/map-shift.h our real makefile
target, and add this a dependency of the top level build target.

Link: http://lkml.kernel.org/r/20180503192430.7582-2-ross.zwisler@linux.intel.comSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: CR, Sapthagirish <sapthagirish.cr@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Many places in drivers/ file systems, error was handled in a common way
like below:

	ret = (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;

vmf_error() will replace this and return vm_fault_t type err.

A lot of drivers and filesystems currently have a rather complex mapping
of errno-to-VM_FAULT code.  We have been able to eliminate a lot of it
by just returning VM_FAULT codes directly from functions which are
called exclusively from the fault handling path.

Some functions can be called both from the fault handler and other
context which are expecting an errno, so they have to continue to return
an errno.  Some users still need to choose different behaviour for
different errnos, but vmf_error() captures the essential error
translation that's common to all users, and those that need to handle
additional errors can handle them first.

Link: http://lkml.kernel.org/r/20180510174826.GA14268@jordon-HP-15-Notebook-PCSigned-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I had neglected to increment the error counter when the tests failed,
which made the tests noisy when they fail, but not actually return an
error code.

Link: http://lkml.kernel.org/r/20180509114328.9887-1-mpe@ellerman.id.au
Fixes: 3cc78125 ("lib/test_bitmap.c: add optimisation tests")
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Yury Norov <ynorov@caviumnetworks.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: <stable@vger.kernel.org>	[4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull powerpc fixes from Michael Ellerman:
 "Just three commits.

  The two cxl ones are not fixes per se, but they modify code that was
  added this cycle so that it will work with a recent firmware change.

  And then a fix for a recent commit that added sleeps in the NVRAM
  code, which needs to be more careful and not sleep if eg. we're called
  in the panic() path.

  Thanks to Nicholas Piggin, Philippe Bergheaud, Christophe Lombard"

* tag 'powerpc-4.17-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powernv: Fix NVRAM sleep in invalid context when crashing
  cxl: Report the tunneled operations status
  cxl: Set the PBCQ Tunnel BAR register when enabling capi mode

Pull ACPI fix from Rafael Wysocki:
 "Fix an ACPICA regression introduced in this cycle and related to the
  handling of package objects loaded by the Load and loadTable AML
  operators that are not initialized properly after recent changes (Bob
  Moore)"

* tag 'acpi-4.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPICA: Add deferred package support for the Load and loadTable operators

Pull power management fix from Rafael Wysocki:
 "Fix Kconfig dependencies of the armada-37xx cpufreq driver (Miquel
  Raynal)"

* tag 'pm-4.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: armada-37xx: driver relies on cpufreq-dt

Pull USB fixes from Greg KH:
 "Here are some USB driver fixes fro 4.17-rc6.

  They resolve some reported bugs in the musb driver, the xhci driver,
  and a number of small fixes for the usbip driver.

  All of these have been in linux-next with no reported issues"

* tag 'usb-4.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usbip: usbip_host: fix bad unlock balance during stub_probe()
  usbip: usbip_host: fix NULL-ptr deref and use-after-free errors
  usbip: usbip_host: run rebind from exit when module is removed
  usbip: usbip_host: delete device from busid_table after rebind
  usbip: usbip_host: refine probe and disconnect debug msgs to be useful
  usb: musb: fix remote wakeup racing with suspend
  xhci: Fix USB3 NULL pointer dereference at logical disconnect.

Pull block fix from Jens Axboe:
 "Single fix this time, from Coly, fixing a failure case when
  CONFIG_DEBUGFS isn't enabled"

* tag 'for-linus-20180518' of git://git.kernel.dk/linux-block:
  bcache: return 0 from bch_debug_init() if CONFIG_DEBUG_FS=n

Pull spi fixes from Mark Brown:
 "A small collection of fixes accumilated since the merge window, all
  fairly small and driver specific"

* tag 'spi-fix-v4.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: bcm2835aux: ensure interrupts are enabled for shared handler
  spi: bcm-qspi: Always read and set BSPI_MAST_N_BOOT_CTRL
  spi: bcm-qspi: Avoid setting MSPI_CDRAM_PCS for spi-nor master
  spi: pxa2xx: Allow 64-bit DMA
  spi: cadence: Add usleep_range() for cdns_spi_fill_tx_fifo()
  spi: sh-msiof: Fix bit field overflow writes to TSCR/RSCR
  spi: imx: Update MODULE_DESCRIPTION to "SPI Controller driver"

Pull mtd fixes from Boris Brezillon:
 "NAND fixes:
   - Fix read path of the Marvell NAND driver
   - Make sure we don't pass a u64 to ndelay()

  CFI fix:
   - Fix the map_word_andequal() implementation"

* tag 'mtd/fixes-for-4.17-rc6' of git://git.infradead.org/linux-mtd:
  mtd: rawnand: Fix return type of __DIVIDE() when called with 32-bit
  mtd: rawnand: marvell: Fix read logic for layouts with ->nchunks > 2
  mtd: Fix comparison in map_word_andequal()

Pull drm fixes from Dave Airlie:
 "Pretty quiet week again: one vmwgfx regression fix, one core buffer
  overflow fix, one vc4 leak fix and three i915 fixes"

* tag 'drm-fixes-for-v4.17-rc6' of git://people.freedesktop.org/~airlied/linux:
  drm/dumb-buffers: Integer overflow in drm_mode_create_ioctl()
  drm/i915/gen9: Add WaClearHIZ_WM_CHICKEN3 for bxt and glk
  drm/vmwgfx: Set dmabuf_size when vmw_dmabuf_init is successful
  drm/vc4: Fix leak of the file_priv that stored the perfmon.
  drm/i915/execlists: Use rmb() to order CSB reads
  drm/i915/userptr: reject zero user_size
  drm: Match sysfs name in link removal to link creation

Merge tag 'drm-intel-fixes-2018-05-17' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

- Userptr IOCTL zero size check (Matt)
- Two hardware quirk fixes (Michel & Chris)

* tag 'drm-intel-fixes-2018-05-17' of git://anongit.freedesktop.org/drm/drm-intel:
  drm/i915/gen9: Add WaClearHIZ_WM_CHICKEN3 for bxt and glk
  drm/i915/execlists: Use rmb() to order CSB reads
  drm/i915/userptr: reject zero user_size

Merge tag 'hwmon-for-linus-v4.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:
 "Two k10temp fixes:

   - fix race condition when accessing System Management Network
     registers

   - fix reading critical temperatures on F15h M60h and M70h

  Also add PCI ID's for the AMD Raven Ridge root bridge"

* tag 'hwmon-for-linus-v4.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (k10temp) Use API function to access System Management Network
  x86/amd_nb: Add support for Raven Ridge CPUs
  hwmon: (k10temp) Fix reading critical temperature register

Pull kvm fixes from Paolo Bonzini:

 - ARM/ARM64 locking fixes

 - x86 fixes: PCID, UMIP, locking

 - improved support for recent Windows version that have a 2048 Hz APIC
   timer

 - rename KVM_HINTS_DEDICATED CPUID bit to KVM_HINTS_REALTIME

 - better behaved selftests

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: rename KVM_HINTS_DEDICATED to KVM_HINTS_REALTIME
  KVM: arm/arm64: VGIC/ITS save/restore: protect kvm_read_guest() calls
  KVM: arm/arm64: VGIC/ITS: protect kvm_read_guest() calls with SRCU lock
  KVM: arm/arm64: VGIC/ITS: Promote irq_lock() in update_affinity
  KVM: arm/arm64: Properly protect VGIC locks from IRQs
  KVM: X86: Lower the default timer frequency limit to 200us
  KVM: vmx: update sec exec controls for UMIP iff emulating UMIP
  kvm: x86: Suppress CR3_PCID_INVD bit only when PCIDs are enabled
  KVM: selftests: exit with 0 status code when tests cannot be run
  KVM: hyperv: idr_find needs RCU protection
  x86: Delay skip of emulated hypercall instruction
  KVM: Extend MAX_IRQ_ROUTES to 4096 for all archs

Pull sound fixes from Takashi Iwai:
 "We have a core fix in the compat code for covering a potential race
  (double references), but it's a very minor change.

  The rest are all small device-specific quirks, as well as a correction
  of the new UAC3 support code"

* tag 'sound-4.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Use Class Specific EP for UAC3 devices.
  ALSA: hda/realtek - Clevo P950ER ALC1220 Fixup
  ALSA: usb: mixer: volume quirk for CM102-A+/102S+
  ALSA: hda: Add Lenovo C50 All in one to the power_save blacklist
  ALSA: control: fix a redundant-copy issue

KVM_HINTS_DEDICATED seems to be somewhat confusing:

Guest doesn't really care whether it's the only task running on a host
CPU as long as it's not preempted.

And there are more reasons for Guest to be preempted than host CPU
sharing, for example, with memory overcommit it can get preempted on a
memory access, post copy migration can cause preemption, etc.

Let's call it KVM_HINTS_REALTIME which seems to better
match what guests expect.

Also, the flag most be set on all vCPUs - current guests assume this.
Note so in the documentation.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull s390 fixes from Martin Schwidefsky:

 - a fix for the vfio ccw translation code

 - update an incorrect email address in the MAINTAINERS file

 - fix a division by zero oops in the cpum_sf code found by trinity

 - two fixes for the error handling of the qdio code

 - several spectre related patches to convert all left-over indirect
   branches in the kernel to expoline branches

 - update defconfigs to avoid warnings due to the netfilter Kconfig
   changes

 - avoid several compiler warnings in the kexec_file code for s390

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/qdio: don't release memory in qdio_setup_irq()
  s390/qdio: fix access to uninitialized qdio_q fields
  s390/cpum_sf: ensure sample frequency of perf event attributes is non-zero
  s390: use expoline thunks in the BPF JIT
  s390: extend expoline to BC instructions
  s390: remove indirect branch from do_softirq_own_stack
  s390: move spectre sysfs attribute code
  s390/kernel: use expoline for indirect branches
  s390/ftrace: use expoline for indirect branches
  s390/lib: use expoline for indirect branches
  s390/crc32-vx: use expoline for indirect branches
  s390: move expoline assembler macros to a header
  vfio: ccw: fix cleanup if cp_prefetch fails
  s390/kexec_file: add declaration of purgatory related globals
  s390: update defconfigs
  MAINTAINERS: update s390 zcrypt maintainers email address

Pull SELinux fixes from Paul Moore:
 "A small pull request to fix a few regressions in the SELinux/SCTP code
  with applications that call bind() with AF_UNSPEC/INADDR_ANY.

  The individual commit descriptions have more information, but the
  commits themselves should be self explanatory"

* tag 'selinux-pr-20180516' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: correctly handle sa_family cases in selinux_sctp_bind_connect()
  selinux: fix address family in bind() and connect() to match address/port
  selinux: add AF_UNSPEC and INADDR_ANY checks to selinux_socket_bind()

proc_pid_cmdline_read() and environ_read() directly access the target
process' VM to retrieve the command line and environment. If this
process remaps these areas onto a file via mmap(), the requesting
process may experience various issues such as extra delays if the
underlying device is slow to respond.

Let's simply refuse to access file-backed areas in these functions.
For this we add a new FOLL_ANON gup flag that is passed to all calls
to access_remote_vm(). The code already takes care of such failures
(including unmapped areas). Accesses via /proc/pid/mem were not
changed though.

This was assigned CVE-2018-1120.

Note for stable backports: the patch may apply to kernels prior to 4.11
but silently miss one location; it must be checked that no call to
access_remote_vm() keeps zero as the last argument.
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 539d39eb ("bcache: fix wrong return value in bch_debug_init()")
returns the return value of debugfs_create_dir() to bcache_init(). When
CONFIG_DEBUG_FS=n, bch_debug_init() always returns 1 and makes
bcache_init() failedi.

This patch makes bch_debug_init() always returns 0 if CONFIG_DEBUG_FS=n,
so bcache can continue to work for the kernels which don't have debugfs
enanbled.

Changelog:
v4: Add Acked-by from Kent Overstreet.
v3: Use IS_ENABLED(CONFIG_DEBUG_FS) to replace #ifdef DEBUG_FS.
v2: Remove a warning information
v1: Initial version.

Fixes: Commit 539d39eb ("bcache: fix wrong return value in bch_debug_init()")
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Reported-by: Massimo B. <massimo.b@gmx.net>
Reported-by: Kai Krakow <kai@kaishome.de>
Tested-by: Kai Krakow <kai@kaishome.de>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Similarly to opal_event_shutdown, opal_nvram_write can be called in
the crash path with irqs disabled. Special case the delay to avoid
sleeping in invalid context.

Fixes: 3b807033 ("powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops")
Cc: stable@vger.kernel.org # v3.2
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

A single fix for a recent regression.

* 'vmwgfx-fixes-4.17' of git://people.freedesktop.org/~thomash/linux:
  drm/vmwgfx: Set dmabuf_size when vmw_dmabuf_init is successful

- core: Fix regression in dev node offsets (Haneen)
- vc4: Fix memory leak on driver close (Eric)
- dumb-buffers: Prevent overflow in DIV_ROUND_UP() (Dan)

Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Dan Carpenter <dan.carpenter@oracle.com>

* tag 'drm-misc-fixes-2018-05-16' of git://anongit.freedesktop.org/drm/drm-misc:
  drm/dumb-buffers: Integer overflow in drm_mode_create_ioctl()
  drm/vc4: Fix leak of the file_priv that stored the perfmon.
  drm: Match sysfs name in link removal to link creation

Pull tracing fix from Steven Rostedt:
 "Some of the ftrace internal events use a zero for a data size of a
  field event. This is increasingly important for the histogram trigger
  work that is being extended.

  While auditing trace events, I found that a couple of the xen events
  were used as just marking that a function was called, by creating a
  static array of size zero. This can play havoc with the tracing
  features if these events are used, because a zero size of a static
  array is denoted as a special nul terminated dynamic array (this is
  what the trace_marker code uses). But since the xen events have no
  size, they are not nul terminated, and unexpected results may occur.

  As trace events were never intended on being a marker to denote that a
  function was hit or not, especially since function tracing and kprobes
  can trivially do the same, the best course of action is to simply
  remove these events"

* tag 'trace-v4.17-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/x86/xen: Remove zero data size trace events trace_xen_mmu_flush_tlb{_all}

Merge tag 'trace-v4.17-rc5-vsprintf' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull memory barrier for from Steven Rostedt:
 "The memory barrier usage in updating the random ptr hash for %p in
  vsprintf is incorrect.

  Instead of adding the read memory barrier into vsprintf() which will
  cause a slight degradation to a commonly used function in the kernel
  just to solve a very unlikely race condition that can only happen at
  boot up, change the code from using a variable branch to a
  static_branch.

  Not only does this solve the race condition, it actually will improve
  the performance of vsprintf() by removing the conditional branch that
  is only needed at boot"

* tag 'trace-v4.17-rc5-vsprintf' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  vsprintf: Replace memory barrier with static_key for random_ptr_key update

stub_probe() calls put_busid_priv() in an error path when device isn't
found in the busid_table. Fix it by making put_busid_priv() safe to be
called with null struct bus_id_priv pointer.

This problem happens when "usbip bind" is run without loading usbip_host
driver and then running modprobe. The first failed bind attempt unbinds
the device from the original driver and when usbip_host is modprobed,
stub_probe() runs and doesn't find the device in its busid table and calls
put_busid_priv(0 with null bus_id_priv pointer.

usbip-host 3-10.2: 3-10.2 is not in match_busid table...  skip!

[  367.359679] =====================================
[  367.359681] WARNING: bad unlock balance detected!
[  367.359683] 4.17.0-rc4+ #5 Not tainted
[  367.359685] -------------------------------------
[  367.359688] modprobe/2768 is trying to release lock (
[  367.359689]
==================================================================
[  367.359696] BUG: KASAN: null-ptr-deref in print_unlock_imbalance_bug+0x99/0x110
[  367.359699] Read of size 8 at addr 0000000000000058 by task modprobe/2768

[  367.359705] CPU: 4 PID: 2768 Comm: modprobe Not tainted 4.17.0-rc4+ #5

Fixes: 22076557 ("usbip: usbip_host: fix NULL-ptr deref and use-after-free errors") in usb-linus
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a comment here which says that DIV_ROUND_UP() and that's where
the problem comes from.  Say you pick:

	args->bpp = UINT_MAX - 7;
	args->width = 4;
	args->height = 1;

The integer overflow in DIV_ROUND_UP() means "cpp" is UINT_MAX / 8 and
because of how we picked args->width that means cpp < UINT_MAX / 4.

I've fixed it by preventing the integer overflow in DIV_ROUND_UP().  I
removed the check for !cpp because it's not possible after this change.
I also changed all the 0xffffffffU references to U32_MAX.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180516140026.GA19340@mwanda

Reviewing Tobin's patches for getting pointers out early before
entropy has been established, I noticed that there's a lone smp_mb() in
the code. As with most lone memory barriers, this one appears to be
incorrectly used.

We currently basically have this:

	get_random_bytes(&ptr_key, sizeof(ptr_key));
	/*
	 * have_filled_random_ptr_key==true is dependent on get_random_bytes().
	 * ptr_to_id() needs to see have_filled_random_ptr_key==true
	 * after get_random_bytes() returns.
	 */
	smp_mb();
	WRITE_ONCE(have_filled_random_ptr_key, true);

And later we have:

	if (unlikely(!have_filled_random_ptr_key))
		return string(buf, end, "(ptrval)", spec);

/* Missing memory barrier here. */

	hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);

As the CPU can perform speculative loads, we could have a situation
with the following:

	CPU0				CPU1
	----				----
				   load ptr_key = 0
   store ptr_key = random
   smp_mb()
   store have_filled_random_ptr_key

				   load have_filled_random_ptr_key = true

				    BAD BAD BAD! (you're so bad!)

Because nothing prevents CPU1 from loading ptr_key before loading
have_filled_random_ptr_key.

But this race is very unlikely, but we can't keep an incorrect smp_mb() in
place. Instead, replace the have_filled_random_ptr_key with a static_branch
not_filled_random_ptr_key, that is initialized to true and changed to false
when we get enough entropy. If the update happens in early boot, the
static_key is updated immediately, otherwise it will have to wait till
entropy is filled and this happens in an interrupt handler which can't
enable a static_key, as that requires a preemptible context. In that case, a
work_queue is used to enable it, as entropy already took too long to
establish in the first place waiting a little more shouldn't hurt anything.

The benefit of using the static key is that the unlikely branch in
vsprintf() now becomes a nop.

Link: http://lkml.kernel.org/r/20180515100558.21df515e@gandalf.local.home

Cc: stable@vger.kernel.org
Fixes: ad67b74d ("printk: hash addresses printed with %p")
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Factor in clear values wherever required while updating destination
min/max.

References: HSDES#1604444184
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Cc: mesa-dev@lists.freedesktop.org
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180510200708.18097-1-michel.thierry@intel.com
Cc: stable@vger.kernel.org
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180514165445.9198-1-michel.thierry@intel.com
(backported from commit 0c79f9cb)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

SOU primary plane prepare_fb hook depends upon dmabuf_size to pin up BO
(and not call a new vmw_dmabuf_init) when a new fb size is same as
current fb. This was changed in a recent commit which is causing
page_flip to fail on VM with low display memory and multi-mon failure
when cycle monitors from secondary display.

Cc: <stable@vger.kernel.org> # 4.14, 4.16
Fixes: 20fb5a63 ("drm/vmwgfx: Unpin the screen object backup buffer when not used")
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>

Pull AFS fixes from David Howells:
 "Here's a set of patches that fix a number of bugs in the in-kernel AFS
  client, including:

   - Fix directory locking to not use individual page locks for
     directory reading/scanning but rather to use a semaphore on the
     afs_vnode struct as the directory contents must be read in a single
     blob and data from different reads must not be mixed as the entire
     contents may be shuffled about between reads.

   - Fix address list parsing to handle port specifiers correctly.

   - Only give up callback records on a server if we actually talked to
     that server (we might not be able to access a server).

   - Fix some callback handling bugs, including refcounting,
     whole-volume callbacks and when callbacks actually get broken in
     response to a CB.CallBack op.

   - Fix some server/address rotation bugs, including giving up if we
     can't probe a server; giving up if a server says it doesn't have a
     volume, but there are more servers to try.

   - Fix the decoding of fetched statuses to be OpenAFS compatible.

   - Fix the handling of server lookups in Cache Manager ops (such as
     CB.InitCallBackState3) to use a UUID if possible and to handle no
     server being found.

   - Fix a bug in server lookup where not all addresses are compared.

   - Fix the non-encryption of calls that prevents some servers from
     being accessed (this also requires an AF_RXRPC patch that has
     already gone in through the net tree).

  There's also a patch that adds tracepoints to log Cache Manager ops
  that don't find a matching server, either by UUID or by address"

* tag 'afs-fixes-20180514' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix the non-encryption of calls
  afs: Fix CB.CallBack handling
  afs: Fix whole-volume callback handling
  afs: Fix afs_find_server search loop
  afs: Fix the handling of an unfound server in CM operations
  afs: Add a tracepoint to record callbacks from unlisted servers
  afs: Fix the handling of CB.InitCallBackState3 to find the server by UUID
  afs: Fix VNOVOL handling in address rotation
  afs: Fix AFSFetchStatus decoder to provide OpenAFS compatibility
  afs: Fix server rotation's handling of fileserver probe failure
  afs: Fix refcounting in callback registration
  afs: Fix giving up callbacks on server destruction
  afs: Fix address list parsing
  afs: Fix directory page locking

Pull SCSI fixes from James Bottomley:
 "Two small driver fixes: aacraid to fix an unknown IU type on task
  management functions which causes a firmware fault and vmw_pvscsi to
  change a return code to retry the operation instead of causing an
  immediate error"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: aacraid: Correct hba_send to include iu_type
  scsi: vmw-pvscsi: return DID_BUS_BUSY for adapter-initated aborts

Pull drm fix from Dave Airlie:
 "This fixes the mmap regression reported to me on irc by an i686 kernel
  user today, he's tested the fix works, and I've audited all the drm
  drivers for the bad mmap usage and since we use the mmap offset as a
  lookup in a table we aren't inclined to have anything bad in there"

[ See commit be83bbf8 ("mmap: introduce sane default mmap limits")
  for details and the note on why the GPU drivers were expected to be a
  special case.    - Linus ]

* tag 'drm-fixes-for-v4.17-rc6-urgent' of git://people.freedesktop.org/~airlied/linux:
  drm: set FMODE_UNSIGNED_OFFSET for drm files

The __DIVIDE() macro checks whether it is called with a 32-bit or 64-bit
dividend, to select the appropriate divide-and-round-up routine.
As the check uses the ternary operator, the result will always be
promoted to a type that can hold both results, i.e. unsigned long long.

When using this result in a division on a 32-bit system, this may lead
to link errors like:

    ERROR: "__udivdi3" [drivers/mtd/nand/raw/nand.ko] undefined!

Fix this by casting the result of the division to the type of the
dividend.

Fixes: 8878b126 ("mtd: nand: add ->exec_op() implementation")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

kvm_read_guest() will eventually look up in kvm_memslots(), which requires
either to hold the kvm->slots_lock or to be inside a kvm->srcu critical
section.
In contrast to x86 and s390 we don't take the SRCU lock on every guest
exit, so we have to do it individually for each kvm_read_guest() call.
Use the newly introduced wrapper for that.

Cc: Stable <stable@vger.kernel.org> # 4.12+
Reported-by: Jan Glauber <jan.glauber@caviumnetworks.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm_read_guest() will eventually look up in kvm_memslots(), which requires
either to hold the kvm->slots_lock or to be inside a kvm->srcu critical
section.
In contrast to x86 and s390 we don't take the SRCU lock on every guest
exit, so we have to do it individually for each kvm_read_guest() call.

Provide a wrapper which does that and use that everywhere.

Note that ending the SRCU critical section before returning from the
kvm_read_guest() wrapper is safe, because the data has been *copied*, so
we don't need to rely on valid references to the memslot anymore.

Cc: Stable <stable@vger.kernel.org> # 4.8+
Reported-by: Jan Glauber <jan.glauber@caviumnetworks.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>