The API surrounding refcount_t should be used in place of atomic_t
when variables are being used as reference counters.  This API can
prevent issues such as counter overflows and use-after-free
conditions.  Within the dm zoned target stack, the atomic_t API is
used for bioctx->ref and cw->refcount.  Change these to use
refcount_t, avoiding the issues mentioned.
Signed-off-by: John Pittman <jpittman@redhat.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

The API surrounding refcount_t should be used in place of atomic_t
when variables are being used as reference counters.  It can
potentially prevent reference counter overflows and use-after-free
conditions.  In the dm thin layer, one such example is tc->refcount.
Change this from the atomic_t API to the refcount_t API to prevent
mentioned conditions.
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Now that request-based DM (multipath) is blk-mq only: this restriction
is required while the legacy request-based IO path still exists.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Now that request-based DM is only using blk-mq, there is no need to
differentiate between legacy "rq" and new "mq".  We're back to a single
request-based DM -- and there was much rejoicing!
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm supports both, and since we're killing off the legacy path in
general, get rid of it in dm.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

The dm-linear target is independent of the dm-zoned target. For code
requiring support for zoned block devices, use CONFIG_BLK_DEV_ZONED
instead of CONFIG_DM_ZONED.

While at it, similarly to dm linear, also enable the DM_TARGET_ZONED_HM
feature in dm-flakey only if CONFIG_BLK_DEV_ZONED is defined.

Fixes: beb9caac ("dm linear: eliminate linear_end_io call if CONFIG_DM_ZONED disabled")
Fixes: 0be12c1c ("dm linear: add support for zoned block devices")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

It is best to avoid any extra overhead associated with bio completion.
DM core will indirectly call a DM target's .end_io if it is defined.
In the case of DM linear, there is no need to do so (for every bio that
completes) if CONFIG_DM_ZONED is not enabled.

Avoiding an extra indirect call for every bio completion is very
important for ensuring DM linear doesn't incur more overhead that
further widens the performance gap between dm-linear and raw block
devices.

Fixes: 0be12c1c ("dm linear: add support for zoned block devices")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

If dm-linear or dm-flakey are layered on top of a partition of a zoned
block device, remapping of the start sector and write pointer position
of the zones reported by a report zones BIO must be modified to account
for the target table entry mapping (start offset within the device and
entry mapping with the dm device).  If the target's backing device is a
partition of a whole disk, the start sector on the physical device of
the partition must also be accounted for when modifying the zone
information.  However, dm_remap_zone_report() was not considering this
last case, resulting in incorrect zone information remapping with
targets using disk partitions.

Fix this by calculating the target backing device start sector using
the position of the completed report zones BIO and the unchanged
position and size of the original report zone BIO. With this value
calculated, the start sector and write pointer position of the target
zones can be correctly remapped.

Fixes: 10999307 ("dm: introduce dm_remap_zone_report()")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Commit 7e6358d2 ("dm: fix various targets to dm_register_target
after module __init resources created") inadvertently introduced this
bug when it moved dm_register_target() after the call to KMEM_CACHE().

Fixes: 7e6358d2 ("dm: fix various targets to dm_register_target after module __init resources created")
Cc: stable@vger.kernel.org
Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

I wrote:
  "Char/Misc fixes for 4.19-rc7

   Here are 8 small fixes for some char/misc driver issues

   Included here are:
	- fpga driver fixes
	- thunderbolt bugfixes
	- firmware core revert/fix
	- hv core fix
	- hv tool fix

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

* tag 'char-misc-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  thunderbolt: Initialize after IOMMUs
  thunderbolt: Do not handle ICM events after domain is stopped
  firmware: Always initialize the fw_priv list object
  docs: fpga: document fpga manager flags
  fpga: bridge: fix obvious function documentation error
  tools: hv: fcopy: set 'error' in case an unknown operation was requested
  fpga: do not access region struct after fpga_region_unregister
  Drivers: hv: vmbus: Use get/put_cpu() in vmbus_connect()

I wrote:
  "Serial driver fixes for 4.19-rc7

   Here are 3 small serial driver fixes for 4.19-rc7
    - 2 sh-sci bugfixes for reported issues
    - a revert of the PM handling for the 8250_dw code

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

* tag 'tty-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "serial: sh-sci: Allow for compressed SCIF address"
  Revert "serial: sh-sci: Remove SCIx_RZ_SCIFA_REGTYPE"
  Revert "serial: 8250_dw: Fix runtime PM handling"

I wrote:
  "USB fixes for 4.19-rc7

   Here are some small USB fixes for 4.19-rc7

   These include:
     - the usual xhci bugfixes for reported issues
     - some new serial driver device ids
     - bugfix for the option serial driver for some devices
     - bugfix for the cdc_acm driver that has been there for a long time.

   All of these have been in linux-next for a while with no reported
   issues."

* tag 'usb-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: xhci-mtk: resume USB3 roothub first
  xhci: Add missing CAS workaround for Intel Sunrise Point xHCI
  usb: cdc_acm: Do not leak URB buffers
  USB: serial: simple: add Motorola Tetra MTP6550 id
  USB: serial: option: add two-endpoints device-id flag
  USB: serial: option: improve Quectel EP06 detection

Wolfram writes:
  "i2c for 4.19

   I2C has three driver bugfixes and a fix for a typo for you."

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: designware: Call i2c_dw_clk_rate() only when calculating timings
  i2c: i2c-scmi: fix for i2c_smbus_write_block_data
  i2c: i2c-isch: fix spelling mistake "unitialized" -> "uninitialized"
  i2c: i2c-qcom-geni: Properly handle DMA safe buffers

James writes:
  "SCSI fixes on 20181006

   Small fix for an unititialized mutex in the qedi driver."

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: qedi: Initialize the stats mutex lock

Michael writes:
  "powerpc fixes for 4.19 #4

   Four regression fixes.

   A fix for a change to lib/xz which broke our zImage loader when
   building with XZ compression. OK'ed by Herbert who merged the
   original patch.

   The recent fix we did to avoid patching __init text broke some 32-bit
   machines, fix that.

   Our show_user_instructions() could be tricked into printing kernel
   memory, add a check to avoid that.

   And a fix for a change to our NUMA initialisation logic, which causes
   crashes in some kdump configurations.

   Thanks to:
     Christophe Leroy, Hari Bathini, Jann Horn, Joel Stanley, Meelis
     Roos, Murilo Opsfelder Araujo, Srikar Dronamraju."

* tag 'powerpc-4.19-4' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/numa: Skip onlining a offline node in kdump path
  powerpc: Don't print kernel instructions in show_user_instructions()
  powerpc/lib: fix book3s/32 boot failure due to code patching
  lib/xz: Put CRC32_POLY_LE in xz_private.h

Dave writes:
  "Networking fixes:

  1) Fix truncation of 32-bit right shift in bpf, from Jann Horn.

  2) Fix memory leak in wireless wext compat, from Stefan Seyfried.

  3) Use after free in cfg80211's reg_process_hint(), from Yu Zhao.

  4) Need to cancel pending work when unbinding in smsc75xx otherwise
     we oops, also from Yu Zhao.

  5) Don't allow enslaving a team device to itself, from Ido Schimmel.

  6) Fix backwards compat with older userspace for rtnetlink FDB dumps.
     From Mauricio Faria.

  7) Add validation of tc policy netlink attributes, from David Ahern.

  8) Fix RCU locking in rawv6_send_hdrinc(), from Wei Wang."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (26 commits)
  net: mvpp2: Extract the correct ethtype from the skb for tx csum offload
  ipv6: take rcu lock in rawv6_send_hdrinc()
  net: sched: Add policy validation for tc attributes
  rtnetlink: fix rtnl_fdb_dump() for ndmsg header
  yam: fix a missing-check bug
  net: bpfilter: Fix type cast and pointer warnings
  net: cxgb3_main: fix a missing-check bug
  bpf: 32-bit RSH verification must truncate input before the ALU op
  net: phy: phylink: fix SFP interface autodetection
  be2net: don't flip hw_features when VXLANs are added/deleted
  net/packet: fix packet drop as of virtio gso
  net: dsa: b53: Keep CPU port as tagged in all VLANs
  openvswitch: load NAT helper
  bnxt_en: get the reduced max_irqs by the ones used by RDMA
  bnxt_en: free hwrm resources, if driver probe fails.
  bnxt_en: Fix enables field in HWRM_QUEUE_COS2BW_CFG request
  bnxt_en: Fix VNIC reservations on the PF.
  team: Forbid enslaving team device to itself
  net/usb: cancel pending work when unbinding smsc75xx
  mlxsw: spectrum: Delete RIF when VLAN device is removed
  ...

* akpm:
  mm: madvise(MADV_DODUMP): allow hugetlbfs pages
  ocfs2: fix locking for res->tracking and dlm->tracking_list
  mm/vmscan.c: fix int overflow in callers of do_shrink_slab()
  mm/vmstat.c: skip NR_TLB_REMOTE_FLUSH* properly
  mm/vmstat.c: fix outdated vmstat_text
  proc: restrict kernel stack dumps to root
  mm/hugetlb: add mmap() encodings for 32MB and 512MB page sizes
  mm/migrate.c: split only transparent huge pages when allocation fails
  ipc/shm.c: use ERR_CAST() for shm_lock() error return
  mm/gup_benchmark: fix unsigned comparison to zero in __gup_benchmark_ioctl
  mm, thp: fix mlocking THP page with migration enabled
  ocfs2: fix crash in ocfs2_duplicate_clusters_by_page()
  hugetlb: take PMD sharing into account when flushing tlb/caches
  mm: migration: fix migration of huge PMD shared pages

Reproducer, assuming 2M of hugetlbfs available:

Hugetlbfs mounted, size=2M and option user=testuser

  # mount | grep ^hugetlbfs
  hugetlbfs on /dev/hugepages type hugetlbfs (rw,pagesize=2M,user=dan)
  # sysctl vm.nr_hugepages=1
  vm.nr_hugepages = 1
  # grep Huge /proc/meminfo
  AnonHugePages:         0 kB
  ShmemHugePages:        0 kB
  HugePages_Total:       1
  HugePages_Free:        1
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:       2048 kB
  Hugetlb:            2048 kB

Code:

  #include <sys/mman.h>
  #include <stddef.h>
  #define SIZE 2*1024*1024
  int main()
  {
    void *ptr;
    ptr = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_HUGETLB | MAP_ANONYMOUS, -1, 0);
    madvise(ptr, SIZE, MADV_DONTDUMP);
    madvise(ptr, SIZE, MADV_DODUMP);
  }

Compile and strace:

  mmap(NULL, 2097152, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, -1, 0) = 0x7ff7c9200000
  madvise(0x7ff7c9200000, 2097152, MADV_DONTDUMP) = 0
  madvise(0x7ff7c9200000, 2097152, MADV_DODUMP) = -1 EINVAL (Invalid argument)

hugetlbfs pages have VM_DONTEXPAND in the VmFlags driver pages based on
author testing with analysis from Florian Weimer[1].

The inclusion of VM_DONTEXPAND into the VM_SPECIAL defination was a
consequence of the large useage of VM_DONTEXPAND in device drivers.

A consequence of [2] is that VM_DONTEXPAND marked pages are unable to be
marked DODUMP.

A user could quite legitimately madvise(MADV_DONTDUMP) their hugetlbfs
memory for a while and later request that madvise(MADV_DODUMP) on the same
memory.  We correct this omission by allowing madvice(MADV_DODUMP) on
hugetlbfs pages.

[1] https://stackoverflow.com/questions/52548260/madvisedodump-on-the-same-ptr-size-as-a-successful-madvisedontdump-fails-wit
[2] commit 0103bd16 ("mm: prepare VM_DONTDUMP for using in drivers")

Link: http://lkml.kernel.org/r/20180930054629.29150-1-daniel@linux.ibm.com
Link: https://lists.launchpad.net/maria-discuss/msg05245.html
Fixes: 0103bd16 ("mm: prepare VM_DONTDUMP for using in drivers")
Reported-by: Kenneth Penza <kpenza@gmail.com>
Signed-off-by: Daniel Black <daniel@linux.ibm.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In dlm_init_lockres() we access and modify res->tracking and
dlm->tracking_list without holding dlm->track_lock.  This can cause list
corruptions and can end up in kernel panic.

Fix this by locking res->tracking and dlm->tracking_list with
dlm->track_lock instead of dlm->spinlock.

Link: http://lkml.kernel.org/r/1529951192-4686-1-git-send-email-ashish.samant@oracle.comSigned-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Acked-by: Joseph Qi <jiangqi903@gmail.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

do_shrink_slab() returns unsigned long value, and the placing into int
variable cuts high bytes off.  Then we compare ret and 0xfffffffe (since
SHRINK_EMPTY is converted to ret type).

Thus a large number of objects returned by do_shrink_slab() may be
interpreted as SHRINK_EMPTY, if low bytes of their value are equal to
0xfffffffe.  Fix that by declaration ret as unsigned long in these
functions.

Link: http://lkml.kernel.org/r/153813407177.17544.14888305435570723973.stgit@localhost.localdomainSigned-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5dd0b16c ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even
on UP") made the availability of the NR_TLB_REMOTE_FLUSH* counters inside
the kernel unconditional to reduce #ifdef soup, but (either to avoid
showing dummy zero counters to userspace, or because that code was missed)
didn't update the vmstat_array, meaning that all following counters would
be shown with incorrect values.

This only affects kernel builds with
CONFIG_VM_EVENT_COUNTERS=y && CONFIG_DEBUG_TLBFLUSH=y && CONFIG_SMP=n.

Link: http://lkml.kernel.org/r/20181001143138.95119-2-jannh@google.com
Fixes: 5dd0b16c ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even on UP")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

7a9cdebd ("mm: get rid of vmacache_flush_all() entirely") removed the
VMACACHE_FULL_FLUSHES statistics, but didn't remove the corresponding
entry in vmstat_text.  This causes an out-of-bounds access in
vmstat_show().

Luckily this only affects kernels with CONFIG_DEBUG_VM_VMACACHE=y, which
is probably very rare.

Link: http://lkml.kernel.org/r/20181001143138.95119-1-jannh@google.com
Fixes: 7a9cdebd ("mm: get rid of vmacache_flush_all() entirely")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently, you can use /proc/self/task/*/stack to cause a stack walk on
a task you control while it is running on another CPU.  That means that
the stack can change under the stack walker.  The stack walker does
have guards against going completely off the rails and into random
kernel memory, but it can interpret random data from your kernel stack
as instruction pointers and stack pointers.  This can cause exposure of
kernel stack contents to userspace.

Restrict the ability to inspect kernel stacks of arbitrary tasks to root
in order to prevent a local attacker from exploiting racy stack unwinding
to leak kernel task stack contents.  See the added comment for a longer
rationale.

There don't seem to be any users of this userspace API that can't
gracefully bail out if reading from the file fails.  Therefore, I believe
that this change is unlikely to break things.  In the case that this patch
does end up needing a revert, the next-best solution might be to fake a
single-entry stack based on wchan.

Link: http://lkml.kernel.org/r/20180927153316.200286-1-jannh@google.com
Fixes: 2ec220e2 ("proc: add /proc/*/stack")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ken Chen <kenchen@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ARM64 architecture also supports 32MB and 512MB HugeTLB page sizes.  This
just adds mmap() system call argument encoding for them.

Link: http://lkml.kernel.org/r/1537841300-6979-1-git-send-email-anshuman.khandual@arm.comSigned-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

split_huge_page_to_list() fails on HugeTLB pages.  I was experimenting
with moving 32MB contig HugeTLB pages on arm64 (with a debug patch
applied) and hit the following stack trace when the kernel crashed.

[ 3732.462797] Call trace:
[ 3732.462835]  split_huge_page_to_list+0x3b0/0x858
[ 3732.462913]  migrate_pages+0x728/0xc20
[ 3732.462999]  soft_offline_page+0x448/0x8b0
[ 3732.463097]  __arm64_sys_madvise+0x724/0x850
[ 3732.463197]  el0_svc_handler+0x74/0x110
[ 3732.463297]  el0_svc+0x8/0xc
[ 3732.463347] Code: d1000400 f90b0e60 f2fbd5a2 a94982a1 (f9000420)

When unmap_and_move[_huge_page]() fails due to lack of memory, the
splitting should happen only for transparent huge pages not for HugeTLB
pages.  PageTransHuge() returns true for both THP and HugeTLB pages.
Hence the conditonal check should test PagesHuge() flag to make sure that
given pages is not a HugeTLB one.

Link: http://lkml.kernel.org/r/1537798495-4996-1-git-send-email-anshuman.khandual@arm.com
Fixes: 94723aaf ("mm: unclutter THP migration")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This uses ERR_CAST() instead of an open-coded cast, as it is casting
across structure pointers, which upsets __randomize_layout:

ipc/shm.c: In function `shm_lock':
ipc/shm.c:209:9: note: randstruct: casting between randomized structure pointer types (ssa): `struct shmid_kernel' and `struct kern_ipc_perm'

  return (void *)ipcp;
         ^~~~~~~~~~~~

Link: http://lkml.kernel.org/r/20180919180722.GA15073@beast
Fixes: 82061c57 ("ipc: drop ipc_lock()")
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

get_user_pages_fast() will return negative value if no pages were pinned,
then be converted to a unsigned, which is compared to zero, giving the
wrong result.

Link: http://lkml.kernel.org/r/20180921095015.26088-1-yuehaibing@huawei.com
Fixes: 09e35a4a ("mm/gup_benchmark: handle gup failures")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A transparent huge page is represented by a single entry on an LRU list.
Therefore, we can only make unevictable an entire compound page, not
individual subpages.

If a user tries to mlock() part of a huge page, we want the rest of the
page to be reclaimable.

We handle this by keeping PTE-mapped huge pages on normal LRU lists: the
PMD on border of VM_LOCKED VMA will be split into PTE table.

Introduction of THP migration breaks[1] the rules around mlocking THP
pages.  If we had a single PMD mapping of the page in mlocked VMA, the
page will get mlocked, regardless of PTE mappings of the page.

For tmpfs/shmem it's easy to fix by checking PageDoubleMap() in
remove_migration_pmd().

Anon THP pages can only be shared between processes via fork().  Mlocked
page can only be shared if parent mlocked it before forking, otherwise CoW
will be triggered on mlock().

For Anon-THP, we can fix the issue by munlocking the page on removing PTE
migration entry for the page.  PTEs for the page will always come after
mlocked PMD: rmap walks VMAs from oldest to newest.

Test-case:

	#include <unistd.h>
	#include <sys/mman.h>
	#include <sys/wait.h>
	#include <linux/mempolicy.h>
	#include <numaif.h>

	int main(void)
	{
	        unsigned long nodemask = 4;
	        void *addr;

		addr = mmap((void *)0x20000000UL, 2UL << 20, PROT_READ | PROT_WRITE,
			MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED, -1, 0);

	        if (fork()) {
			wait(NULL);
			return 0;
	        }

	        mlock(addr, 4UL << 10);
	        mbind(addr, 2UL << 20, MPOL_PREFERRED | MPOL_F_RELATIVE_NODES,
	                &nodemask, 4, MPOL_MF_MOVE);

	        return 0;
	}

[1] https://lkml.kernel.org/r/CAOMGZ=G52R-30rZvhGxEbkTw7rLLwBGadVYeo--iizcD3upL3A@mail.gmail.com

Link: http://lkml.kernel.org/r/20180917133816.43995-1-kirill.shutemov@linux.intel.com
Fixes: 616b8371 ("mm: thp: enable thp migration in generic path")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>	[4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ocfs2_duplicate_clusters_by_page() may crash if one of the extent's pages
is dirty.  When a page has not been written back, it is still in dirty
state.  If ocfs2_duplicate_clusters_by_page() is called against the dirty
page, the crash happens.

To fix this bug, we can just unlock the page and wait until the page until
its not dirty.

The following is the backtrace:

kernel BUG at /root/code/ocfs2/refcounttree.c:2961!
[exception RIP: ocfs2_duplicate_clusters_by_page+822]
__ocfs2_move_extent+0x80/0x450 [ocfs2]
? __ocfs2_claim_clusters+0x130/0x250 [ocfs2]
ocfs2_defrag_extent+0x5b8/0x5e0 [ocfs2]
__ocfs2_move_extents_range+0x2a4/0x470 [ocfs2]
ocfs2_move_extents+0x180/0x3b0 [ocfs2]
? ocfs2_wait_for_recovery+0x13/0x70 [ocfs2]
ocfs2_ioctl_move_extents+0x133/0x2d0 [ocfs2]
ocfs2_ioctl+0x253/0x640 [ocfs2]
do_vfs_ioctl+0x90/0x5f0
SyS_ioctl+0x74/0x80
do_syscall_64+0x74/0x140
entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Once we find the page is dirty, we do not wait until it's clean, rather we
use write_one_page() to write it back

Link: http://lkml.kernel.org/r/20180829074740.9438-1-lchen@suse.com
[lchen@suse.com: update comments]
  Link: http://lkml.kernel.org/r/20180830075041.14879-1-lchen@suse.com
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Larry Chen <lchen@suse.com>
Acked-by: Changwei Ge <ge.changwei@h3c.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When fixing an issue with PMD sharing and migration, it was discovered via
code inspection that other callers of huge_pmd_unshare potentially have an
issue with cache and tlb flushing.

Use the routine adjust_range_if_pmd_sharing_possible() to calculate worst
case ranges for mmu notifiers.  Ensure that this range is flushed if
huge_pmd_unshare succeeds and unmaps a PUD_SUZE area.

Link: http://lkml.kernel.org/r/20180823205917.16297-3-mike.kravetz@oracle.comSigned-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The page migration code employs try_to_unmap() to try and unmap the source
page.  This is accomplished by using rmap_walk to find all vmas where the
page is mapped.  This search stops when page mapcount is zero.  For shared
PMD huge pages, the page map count is always 1 no matter the number of
mappings.  Shared mappings are tracked via the reference count of the PMD
page.  Therefore, try_to_unmap stops prematurely and does not completely
unmap all mappings of the source page.

This problem can result is data corruption as writes to the original
source page can happen after contents of the page are copied to the target
page.  Hence, data is lost.

This problem was originally seen as DB corruption of shared global areas
after a huge page was soft offlined due to ECC memory errors.  DB
developers noticed they could reproduce the issue by (hotplug) offlining
memory used to back huge pages.  A simple testcase can reproduce the
problem by creating a shared PMD mapping (note that this must be at least
PUD_SIZE in size and PUD_SIZE aligned (1GB on x86)), and using
migrate_pages() to migrate process pages between nodes while continually
writing to the huge pages being migrated.

To fix, have the try_to_unmap_one routine check for huge PMD sharing by
calling huge_pmd_unshare for hugetlbfs huge pages.  If it is a shared
mapping it will be 'unshared' which removes the page table entry and drops
the reference on the PMD page.  After this, flush caches and TLB.

mmu notifiers are called before locking page tables, but we can not be
sure of PMD sharing until page tables are locked.  Therefore, check for
the possibility of PMD sharing before locking so that notifiers can
prepare for the worst possible case.

Link: http://lkml.kernel.org/r/20180823205917.16297-2-mike.kravetz@oracle.com
[mike.kravetz@oracle.com: make _range_in_vma() a static inline]
  Link: http://lkml.kernel.org/r/6063f215-a5c8-2f0c-465a-2c515ddc952d@oracle.com
Fixes: 39dde65c ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bjorn writes:
  "PCI fixes for v4.19:

   - Reprogram bridge prefetch registers to fix NVIDIA and Radeon issues
     after suspend/resume (Daniel Drake)

   - Fix mvebu I/O mapping creation sequence (Thomas Petazzoni)

   - Fix minor MAINTAINERS file match issue (Bjorn Helgaas)"

* tag 'pci-v4.19-fixes-3' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: mvebu: Fix PCI I/O mapping creation sequence
  MAINTAINERS: Remove obsolete drivers/pci pattern from ACPI section
  PCI: Reprogram bridge prefetch registers on resume

Merge tag 'for-4.19/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Mike writes:
  "device mapper fixes

   - Fix a DM thinp __udivdi3 undefined on 32-bit bug introduced during
     4.19 merge window.

   - Fix leak and dangling pointer in DM multipath's scsi_dh related code.

   - A couple stable@ fixes for DM cache's resize support.

   - A DM raid fix to remove "const" from decipher_sync_action()'s return
     type."

* tag 'for-4.19/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: fix resize crash if user doesn't reload cache table
  dm cache metadata: ignore hints array being too small during resize
  dm raid: remove bogus const from decipher_sync_action() return type
  dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointer
  dm thin metadata: fix __udivdi3 undefined on 32-bit

Linus writes:
  "A single GPIO fix:
   Free the last used descriptor, an off by one error.
   This is tagged for stable as well."

* tag 'gpio-v4.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpiolib: Free the last requested descriptor

Rafael writes:
  "Power management fix for 4.19-rc7

   Fix a bug that may cause runtime PM to misbehave for some devices
   after a failing or aborted system suspend which is nasty enough for
   an -rc7 time frame fix."

* tag 'pm-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / core: Clear the direct_complete flag on errors

Ingo writes:
  "perf fixes:
    - fix a CPU#0 hot unplug bug and a PCI enumeration bug in the x86 Intel uncore PMU driver
    - fix a CPU event enumeration bug in the x86 AMD PMU driver
    - fix a perf ring-buffer corruption bug when using tracepoints
    - fix a PMU unregister locking bug"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/amd/uncore: Set ThreadMask and SliceMask for L3 Cache perf events
  perf/x86/intel/uncore: Fix PCI BDF address of M3UPI on SKX
  perf/ring_buffer: Prevent concurent ring buffer access
  perf/x86/intel/uncore: Use boot_cpu_data.phys_proc_id instead of hardcorded physical package ID 0
  perf/core: Fix perf_pmu_unregister() locking

Ingo writes:
  "x86 fixes:

   Misc fixes:

    - fix various vDSO bugs: asm constraints and retpolines
    - add vDSO test units to make sure they never re-appear
    - fix UV platform TSC initialization bug
    - fix build warning on Clang"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/vdso: Fix vDSO syscall fallback asm constraint regression
  x86/cpu/amd: Remove unnecessary parentheses
  x86/vdso: Only enable vDSO retpolines when enabled and supported
  x86/tsc: Fix UV TSC initialization
  x86/platform/uv: Provide is_early_uv_system()
  selftests/x86: Add clock_gettime() tests to test_vdso
  x86/vdso: Fix asm constraints on vDSO syscall fallbacks

Ingo writes:
  "scheduler fixes:

   These fixes address a rather involved performance regression between
   v4.17->v4.19 in the sched/numa auto-balancing code. Since distros
   really need this fix we accelerated it to sched/urgent for a faster
   upstream merge.

   NUMA scheduling and balancing performance is now largely back to
   v4.17 levels, without reintroducing the NUMA placement bugs that
   v4.18 and v4.19 fixed.

   Many thanks to Srikar Dronamraju, Mel Gorman and Jirka Hladky, for
   reporting, testing, re-testing and solving this rather complex set of
   bugs."

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/numa: Migrate pages to local nodes quicker early in the lifetime of a task
  mm, sched/numa: Remove rate-limiting of automatic NUMA balancing migration
  sched/numa: Avoid task migration for small NUMA improvement
  mm/migrate: Use spin_trylock() while resetting rate limit
  sched/numa: Limit the conditions where scan period is reset
  sched/numa: Reset scan rate whenever task moves across nodes
  sched/numa: Pass destination CPU as a parameter to migrate_task_rq
  sched/numa: Stop multiple tasks from moving to the CPU at the same time

Ingo writes:
  "locking fixes:

   A fix in the ww_mutex self-test that produces a scary splat, plus an
   updates to the maintained-filed patters in MAINTAINER."

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/ww_mutex: Fix runtime warning in the WW mutex selftest
  MAINTAINERS: Remove dead path from LOCKING PRIMITIVES entry