I meet a crash, which could be reproduce:
1) while true; do cat /proc/ipmi/0/version; done
2) modprobe -rv ipmi_si ipmi_msghandler ipmi_devintf

[82761.021137] IPMI BT: req2rsp=5 secs retries=2
[82761.034524] ipmi device interface
[82761.222218] ipmi_si ipmi_si.0: Found new BMC (man_id: 0x0007db, prod_id: 0x0001, dev_id: 0x01)
[82761.222230] ipmi_si ipmi_si.0: IPMI bt interface initialized
[82903.922740] BUG: unable to handle kernel NULL pointer dereference at 00000000000002d4
[82903.930952] IP: [<ffffffffa030d9e8>] smi_version_proc_show+0x18/0x40 [ipmi_msghandler]
[82903.939220] PGD 86693a067 PUD 865304067 PMD 0
[82903.943893] Thread overran stack, or stack corrupted
[82903.949034] Oops: 0000 [#1] SMP
[82903.983091] Modules linked in: ipmi_si(-) ipmi_msghandler binfmt_misc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter
...
[82904.057285]  pps_core scsi_transport_sas dm_mod vfio_iommu_type1 vfio xt_sctp nf_conntrack_proto_sctp nf_nat_proto_sctp
                nf_nat nf_conntrack sctp libcrc32c [last unloaded: ipmi_devintf]
[82904.073169] CPU: 37 PID: 28089 Comm: cat Tainted: GF          O   ---- -------   3.10.0-327.28.3.el7.x86_64 #1
[82904.083373] Hardware name: Huawei RH2288H V3/BC11HGSA0, BIOS 3.22 05/16/2016
[82904.090592] task: ffff880101cc2e00 ti: ffff880369c54000 task.ti: ffff880369c54000
[82904.098414] RIP: 0010:[<ffffffffa030d9e8>]  [<ffffffffa030d9e8>] smi_version_proc_show+0x18/0x40 [ipmi_msghandler]
[82904.109124] RSP: 0018:ffff880369c57e70  EFLAGS: 00010203
[82904.114608] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000024688470
[82904.121912] RDX: fffffffffffffff4 RSI: ffffffffa0313404 RDI: ffff8808670ce200
[82904.129218] RBP: ffff880369c57e70 R08: 0000000000019720 R09: ffffffff81204a27
[82904.136521] R10: ffff88046f803300 R11: 0000000000000246 R12: ffff880662399700
[82904.143828] R13: 0000000000000001 R14: ffff880369c57f48 R15: ffff8808670ce200
[82904.151128] FS:  00007fb70c9ca740(0000) GS:ffff88086e340000(0000) knlGS:0000000000000000
[82904.159557] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[82904.165473] CR2: 00000000000002d4 CR3: 0000000864c0c000 CR4: 00000000003407e0
[82904.172778] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[82904.180084] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[82904.187385] Stack:
[82904.189573]  ffff880369c57ee0 ffffffff81204f1a 00000000122a2427 0000000001426000
[82904.197392]  ffff8808670ce238 0000000000010000 0000000000000000 0000000000000fff
[82904.205198]  00000000122a2427 ffff880862079600 0000000001426000 ffff880369c57f48
[82904.212962] Call Trace:
[82904.219667]  [<ffffffff81204f1a>] seq_read+0xfa/0x3a0
[82904.224893]  [<ffffffff8124ce2d>] proc_reg_read+0x3d/0x80
[82904.230468]  [<ffffffff811e102c>] vfs_read+0x9c/0x170
[82904.235689]  [<ffffffff811e1b7f>] SyS_read+0x7f/0xe0
[82904.240816]  [<ffffffff81649209>] system_call_fastpath+0x16/0x1b
[82904.246991] Code: 30 a0 e8 0c 6f ef e0 5b 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f
               44 00 00 48 8b 47 78 55 48 c7 c6 04 34 31 a0 48 89 e5 48 8b 40 50 <0f>
	       b6 90 d4 02 00 00 31 c0 89 d1 83 e2 0f c0 e9 04 0f b6 c9 e8
[82904.267710] RIP  [<ffffffffa030d9e8>] smi_version_proc_show+0x18/0x40 [ipmi_msghandler]
[82904.276079]  RSP <ffff880369c57e70>
[82904.279734] CR2: 00000000000002d4
[82904.283731] ---[ end trace a69e4328b49dd7c4 ]---
[82904.328118] Kernel panic - not syncing: Fatal exception

Reading versin from /proc need bmc device struct available. So in this patch
we move add/remove_proc_entries between ipmi_bmc_register and ipmi_bmc_unregister.

Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Remove unneeded error handling on the result of a call
to platform_get_resource() when the value is passed to
devm_ioremap_resource().
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

devm_ioremap_resource returns ERR_PTR so we can't check for NULL.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

This patch adds a simple device driver to expose the iBT interface on
Aspeed SOCs (AST2400 and AST2500) as a character device. Such SOCs are
commonly used as BMCs (BaseBoard Management Controllers) and this
driver implements the BMC side of the BT interface.

The BT (Block Transfer) interface is used to perform in-band IPMI
communication between a host and its BMC. Entire messages are buffered
before sending a notification to the other end, host or BMC, that
there is data to be read. Usually, the host emits requests and the BMC
responses but the specification provides a mean for the BMC to send
SMS Attention (BMC-to-Host attention or System Management Software
attention) messages.

For this purpose, the driver introduces a specific ioctl on the
device: 'BT_BMC_IOCTL_SMS_ATN' that can be used by the system running
on the BMC to signal the host of such an event.

The device name defaults to '/dev/ipmi-bt-host'
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
[clg: - checkpatch fixes
      - added a devicetree binding documentation
      - replace 'bt_host' by 'bt_bmc' to reflect that the driver is
        the BMC side of the IPMI BT interface
      - renamed the device to 'ipmi-bt-host'
      - introduced a temporary buffer to copy_{to,from}_user
      - used platform_get_irq()
      - moved the driver under drivers/char/ipmi/ but kept it as a misc
        device
      - changed the compatible cell to "aspeed,ast2400-bt-bmc"
]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
[clg: - checkpatch --strict fixes
      - removed the use of devm_iounmap, devm_kfree in cleanup paths
      - introduced an atomic-t to limit opens to 1
      - introduced a mutex to protect write/read operations]
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Pull libnvdimm fixes from Dan Williams:

 - Four fixes for "flush hint" support.

   Flush hints are addresses advertised by the ACPI 6+ NFIT (NVDIMM
   Firmware Interface Table) that when written and fenced guarantee that
   writes pending in platform write buffers (outside the cpu) have been
   flushed to media.  They might also be used by hypervisors as a
   trigger condition to flush guest-persistent memory ranges to storage.

    Fix a potential data corruption issue, a broken definition of the
    hint array, a wrong allocation size for the unit test implementation
    of the flush hint table, and missing NULL check in an error path.

    The unit test, while it did not prevent these bugs from being
    merged, at least triggered occasional crashes in advance of
    production usages.

 - Fix handling of ACPI DSM error status results.  The DSM mechanism
   allows communication with platform and memory device firmware.  We
   correctly parse known errors, but were silently ignoring others.

   Fix it to consistently fail any command with a non-zero status return
   that we otherwise do not interpret / handle.

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm, region: fix flush hint table thinko
  nfit: fail DSMs that return non-zero status by default
  libnvdimm: fix devm_nvdimm_memremap() error path
  tools/testing/nvdimm: fix allocation range for mock flush hint tables
  nvdimm: fix PHYS_PFN/PFN_PHYS mixup

Merge fixes from Andrew Morton:
 "4 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mem-hotplug: use nodes that contain memory as mask in new_node_page()
  scripts/recordmcount.c: account for .softirqentry.text
  dma-mapping.h: preserve unmap info for CONFIG_DMA_API_DEBUG
  mm,ksm: fix endless looping in allocating memory when ksm enable

9bb627be ("mem-hotplug: don't clear the only node in new_node_page()")
prevents allocating from an empty nodemask, but as David points out, it is
still wrong.  As node_online_map may include memoryless nodes, only
allocating from these nodes is meaningless.

This patch uses node_states[N_MEMORY] mask to prevent the above case.

Fixes: 9bb627be ("mem-hotplug: don't clear the only node in new_node_page()")
Fixes: 394e31d2 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline")
Link: http://lkml.kernel.org/r/1474447117.28370.6.camel@TP420Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

be7635e7 ("arch, ftrace: for KASAN put hard/soft IRQ entries into
separate sections") added .softirqentry.text section, but it was not added
to recordmcount.  So functions in the section are untracable.  Add the
section to scripts/recordmcount.c and scripts/recordmcount.pl.

Fixes: be7635e7 ("arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections")
Link: http://lkml.kernel.org/r/1474902626-73468-1-git-send-email-dvyukov@google.comSigned-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Steve Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>	[4.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When CONFIG_DMA_API_DEBUG is enabled we need to preserve unmapping address
even if "unmap" is a no-op for our architecutre because we need
debug_dma_unmap_page() to correctly cleanup all of the debug bookkeeping.
Failing to do so results in a false positive warnings about previously
mapped areas never being unmapped.

Link: http://lkml.kernel.org/r/1474387125-3713-1-git-send-email-andrew.smirnov@gmail.comSigned-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: "Luis R. Rodriguez" <mcgrof@suse.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Geliang Tang <geliangtang@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I hit the following hung task when runing a OOM LTP test case with 4.1
kernel.

Call trace:
[<ffffffc000086a88>] __switch_to+0x74/0x8c
[<ffffffc000a1bae0>] __schedule+0x23c/0x7bc
[<ffffffc000a1c09c>] schedule+0x3c/0x94
[<ffffffc000a1eb84>] rwsem_down_write_failed+0x214/0x350
[<ffffffc000a1e32c>] down_write+0x64/0x80
[<ffffffc00021f794>] __ksm_exit+0x90/0x19c
[<ffffffc0000be650>] mmput+0x118/0x11c
[<ffffffc0000c3ec4>] do_exit+0x2dc/0xa74
[<ffffffc0000c46f8>] do_group_exit+0x4c/0xe4
[<ffffffc0000d0f34>] get_signal+0x444/0x5e0
[<ffffffc000089fcc>] do_signal+0x1d8/0x450
[<ffffffc00008a35c>] do_notify_resume+0x70/0x78

The oom victim cannot terminate because it needs to take mmap_sem for
write while the lock is held by ksmd for read which loops in the page
allocator

ksm_do_scan
	scan_get_next_rmap_item
		down_read
		get_next_rmap_item
			alloc_rmap_item   #ksmd will loop permanently.

There is no way forward because the oom victim cannot release any memory
in 4.1 based kernel.  Since 4.6 we have the oom reaper which would solve
this problem because it would release the memory asynchronously.
Nevertheless we can relax alloc_rmap_item requirements and use
__GFP_NORETRY because the allocation failure is acceptable as ksm_do_scan
would just retry later after the lock got dropped.

Such a patch would be also easy to backport to older stable kernels which
do not have oom_reaper.

While we are at it add GFP_NOWARN so the admin doesn't have to be alarmed
by the allocation failure.

Link: http://lkml.kernel.org/r/1474165570-44398-1-git-send-email-zhongjiang@huawei.comSigned-off-by: zhong jiang <zhongjiang@huawei.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Suggested-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull late MTD fixes from Brian Norris:
 "Another round of MTD fixes for v4.8

  My apologies for sending this so late.  I've been fairly absent as a
  maintainer this cycle, but I did queue these up weeks ago.  In the
  meantime, Richard was able to handle some other fixes (thanks!) but
  didn't pick these up.

  On the bright side, these are very simple changes that should carry
  little risk.

  Summary:

   - Davinci NAND: fix a long-standing bug in how we clear/prep 4-bit ECC

   - OMAP NAND: an error-handling fix that made it into v4.8-rc1 caused
     error-handling cases in other configurations/code-paths; this fixes
     the fix"

* tag 'for-linus-20160928' of git://git.infradead.org/linux-mtd:
  mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl
  mtd: nand: omap2: Don't call dma_release_channel() if dma_request_chan() failed

I will be starting employment at Versity next week and would like to update
my MAINTAINERS e-mail to reflect that change. My versity e-mail is already
activated so I shouldn't get any bounces on the new one. My ability to help
with Ocfs2 kernel maintenance won't change as a result of the new job.
Signed-off-by: Mark Fasheh <mfasheh@versity.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull cgroup fixes from Tejun Heo:
 "Three late fixes for cgroup: Two cpuset ones, one trivial and the
  other pretty obscure, and a cgroup core fix for a bug which impacts
  cgroup v2 namespace users"

* 'for-4.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix invalid controller enable rejections with cgroup namespace
  cpuset: fix non static symbol warning
  cpuset: handle race between CPU hotplug and cpuset_hotplug_work

Pull tracefs fixes from Steven Rostedt:
 "Al Viro has been looking at the tracefs code, and has pointed out some
  issues.  This contains one fix by me and one by Al.  I'm sure that
  he'll come up with more but for now I tested these patches and they
  don't appear to have any negative impact on tracing"

* tag 'trace-v4.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  fix memory leaks in tracing_buffers_splice_read()
  tracing: Move mutex to protect against resetting of seq data

When building XFS with -Werror, it now fails with:

  include/linux/pagemap.h: In function 'fault_in_multipages_readable':
  include/linux/pagemap.h:602:16: error: variable 'c' set but not used [-Werror=unused-but-set-variable]
    volatile char c;
                  ^

This is a regression caused by commit e23d4159 ("fix
fault_in_multipages_...() on architectures with no-op access_ok()").
Fix it by re-adding the "(void)c" trick taht was previously used to make
the compiler think the variable is used.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The NUMA balancing logic uses an arch-specific PROT_NONE page table flag
defined by pte_protnone() or pmd_protnone() to mark PTEs or huge page
PMDs respectively as requiring balancing upon a subsequent page fault.
User-defined PROT_NONE memory regions which also have this flag set will
not normally invoke the NUMA balancing code as do_page_fault() will send
a segfault to the process before handle_mm_fault() is even called.

However if access_remote_vm() is invoked to access a PROT_NONE region of
memory, handle_mm_fault() is called via faultin_page() and
__get_user_pages() without any access checks being performed, meaning
the NUMA balancing logic is incorrectly invoked on a non-NUMA memory
region.

A simple means of triggering this problem is to access PROT_NONE mmap'd
memory using /proc/self/mem which reliably results in the NUMA handling
functions being invoked when CONFIG_NUMA_BALANCING is set.

This issue was reported in bugzilla (issue 99101) which includes some
simple repro code.

There are BUG_ON() checks in do_numa_page() and do_huge_pmd_numa_page()
added at commit c0e7cad9 to avoid accidentally provoking strange
behaviour by attempting to apply NUMA balancing to pages that are in
fact PROT_NONE.  The BUG_ON()'s are consistently triggered by the repro.

This patch moves the PROT_NONE check into mm/memory.c rather than
invoking BUG_ON() as faulting in these pages via faultin_page() is a
valid reason for reaching the NUMA check with the PROT_NONE page table
flag set and is therefore not always a bug.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=99101Reported-by: Trevor Saunders <tbsaunde@tbsaunde.org>
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull MIPS fixes from Ralf Baechle:
 "A round of 4.8 fixes:

  MIPS generic code:
   - Add a missing ".set pop" in an early commit
   - Fix memory regions reaching top of physical
   - MAAR: Fix address alignment
   - vDSO: Fix Malta EVA mapping to vDSO page structs
   - uprobes: fix incorrect uprobe brk handling
   - uprobes: select HAVE_REGS_AND_STACK_ACCESS_API
   - Avoid a BUG warning during PR_SET_FP_MODE prctl
   - SMP: Fix possibility of deadlock when bringing CPUs online
   - R6: Remove compact branch policy Kconfig entries
   - Fix size calc when avoiding IPIs for small icache flushes
   - Fix pre-r6 emulation FPU initialisation
   - Fix delay slot emulation count in debugfs

  ATH79:
   - Fix test for error return of clk_register_fixed_factor.

  Octeon:
   - Fix kernel header to work for VDSO build.
   - Fix initialization of platform device probing.

  paravirt:
   - Fix undefined reference to smp_bootstrap"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Fix delay slot emulation count in debugfs
  MIPS: SMP: Fix possibility of deadlock when bringing CPUs online
  MIPS: Fix pre-r6 emulation FPU initialisation
  MIPS: vDSO: Fix Malta EVA mapping to vDSO page structs
  MIPS: Select HAVE_REGS_AND_STACK_ACCESS_API
  MIPS: Octeon: Fix platform bus probing
  MIPS: Octeon: mangle-port: fix build failure with VDSO code
  MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)
  MIPS: c-r4k: Fix size calc when avoiding IPIs for small icache flushes
  MIPS: Add a missing ".set pop" in an early commit
  MIPS: paravirt: Fix undefined reference to smp_bootstrap
  MIPS: Remove compact branch policy Kconfig entries
  MIPS: MAAR: Fix address alignment
  MIPS: Fix memory regions reaching top of physical
  MIPS: uprobes: fix incorrect uprobe brk handling
  MIPS: ath79: Fix test for error return of clk_register_fixed_factor().

Pull one more powerpc fix from Michael Ellerman:
 "powernv/pci: Fix m64 checks for SR-IOV and window alignment from
  Russell Currey"

* tag 'powerpc-4.8-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powernv/pci: Fix m64 checks for SR-IOV and window alignment

The fixes to the radix tree test suite show that the multi-order case is
broken.  The basic reason is that the radix tree code uses tagged
pointers with the "internal" bit in the low bits, and calculating the
pointer indices was supposed to mask off those bits.  But gcc will
notice that we then use the index to re-create the pointer, and will
avoid doing the arithmetic and use the tagged pointer directly.

This cleans the code up, using the existing is_sibling_entry() helper to
validate the sibling pointer range (instead of open-coding it), and
using entry_to_node() to mask off the low tag bit from the pointer.  And
once you do that, you might as well just use the now cleaned-up pointer
directly.

[ Side note: the multi-order code isn't actually ever used in the kernel
  right now, and the only reason I didn't just delete all that code is
  that Kirill Shutemov piped up and said:

    "Well, my ext4-with-huge-pages patchset[1] uses multi-order entries.
     It also converts shmem-with-huge-pages and hugetlb to them.

     I'm okay with converting it to other mechanism, but I need
     something.  (I looked into Konstantin's RFC patchset[2].  It looks
     okay, but I don't feel myself qualified to review it as I don't
     know much about radix-tree internals.)"

  [1] http://lkml.kernel.org/r/20160915115523.29737-1-kirill.shutemov@linux.intel.com
  [2] http://lkml.kernel.org/r/147230727479.9957.1087787722571077339.stgit@zurg ]
Reported-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Cedric Blancher <cedric.blancher@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When we replace a multiorder entry, check that all indices reflect the
new value.

Also, compile the test suite with -O2, which shows other problems with
the code due to some dodgy pointer operations in the radix tree code.
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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

The iter->seq can be reset outside the protection of the mutex. So can
reading of user data. Move the mutex up to the beginning of the function.

Fixes: d7350c3f ("tracing/core: make the read callbacks reentrants")
Cc: stable@vger.kernel.org # 2.6.30+
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Commit 432c6bac ("MIPS: Use per-mm page to execute branch delay slot
instructions") accidentally removed use of the MIPS_FPU_EMU_INC_STATS
macro from do_dsemulret, leading to the ds_emul file in debugfs always
returning zero even though we perform delay slot emulations.

Fix this by re-adding the use of the MIPS_FPU_EMU_INC_STATS macro.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 432c6bac ("MIPS: Use per-mm page to execute branch delay slot instructions")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14301/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch fixes the possibility of a deadlock when bringing up
secondary CPUs.
The deadlock occurs because the set_cpu_online() is called before
synchronise_count_slave(). This can cause a deadlock if the boot CPU,
having scheduled another thread, attempts to send an IPI to the
secondary CPU, which it sees has been marked online. The secondary is
blocked in synchronise_count_slave() waiting for the boot CPU to enter
synchronise_count_master(), but the boot cpu is blocked in
smp_call_function_many() waiting for the secondary to respond to it's
IPI request.

Fix this by marking the CPU online in cpu_callin_map and synchronising
counters before declaring the CPU online and calculating the maps for
IPIs.
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Reported-by: Justin Chen <justinpopo6@gmail.com>
Tested-by: Justin Chen <justinpopo6@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: stable@vger.kernel.org # v4.1+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14302/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Pull perf fixes from Thomas Gleixner:
 "Three fixlets for perf:

   - add a missing NULL pointer check in the intel BTS driver

   - make BTS an exclusive PMU because BTS can only handle one event at
     a time

   - ensure that exclusive events are limited to one PMU so that several
     exclusive events can be scheduled on different PMU instances"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Limit matching exclusive events to one PMU
  perf/x86/intel/bts: Make it an exclusive PMU
  perf/x86/intel/bts: Make sure debug store is valid

Pull locking fixes from Thomas Gleixner:
 "Two smallish fixes:

   - use the proper asm constraint in the Super-H atomic_fetch_ops

   - a trivial typo fix in the Kconfig help text"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/hung_task: Fix typo in CONFIG_DETECT_HUNG_TASK help text
  locking/atomic, arch/sh: Fix ATOMIC_FETCH_OP()

Pull EFI fixes from Thomas Gleixner:
 "Two fixes for EFI/PAT:

   - a 32bit overflow bug in the PAT code which was unearthed by the
     large EFI mappings

   - prevent a boot hang on large systems when EFI mixed mode is enabled
     but not used"

* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Only map RAM into EFI page tables if in mixed-mode
  x86/mm/pat: Prevent hang during boot when mapping pages

Pull irq fixes from Thomas Gleixner:
 "Three fixes for irq core and irq chip drivers:

   - Do not set the irq type if type is NONE.  Fixes a boot regression
     on various SoCs

   - Use the proper cpu for setting up the GIC target list.  Discovered
     by the cpumask debugging code.

   - A rather large fix for the MIPS-GIC so per cpu local interrupts
     work again.  This was discovered late because the code falls back
     to slower timers which use normal device interrupts"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/mips-gic: Fix local interrupts
  irqchip/gicv3: Silence noisy DEBUG_PER_CPU_MAPS warning
  genirq: Skip chained interrupt trigger setup if type is IRQ_TYPE_NONE

The definition of the flush hint table as:

	void __iomem *flush_wpq[0][0];

...passed the unit test, but is broken as flush_wpq[0][1] and
flush_wpq[1][0] refer to the same entry.  Fix this to use a helper that
calculates a slot in the table based on the geometry of flush hints in
the region.  This is important to get right since virtualization
solutions use this mechanism to trigger hypervisor flushes to platform
persistence.
Reported-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Merge VM fixes from High Dickins:
 "I get the impression that Andrew is away or busy at the moment, so I'm
  going to send you three independent uncontroversial little mm fixes
  directly - though none is strictly a 4.8 regression fix.

   - shmem: fix tmpfs to handle the huge= option properly from Toshi
     Kani is a one-liner to fix a major embarrassment in 4.8's hugepages
     on tmpfs feature: although Hillf pointed it out in June, somehow
     both Kirill and I repeatedly dropped the ball on this one.  You
     might wonder if the feature got tested at all with that bug in:
     yes, it did, but for wider testing coverage, Kirill and I had each
     relied too much on an override which bypasses that condition.

   - huge tmpfs: fix Committed_AS leak just a run-of-the-mill accounting
     fix in the same feature.

   - mm: delete unnecessary and unsafe init_tlb_ubc() is an unrelated
     fix to 4.3's TLB flush batching in reclaim: the bug would be rare,
     and none of us will be shamed if this one misses 4.8; but it got
     such a quick ack from Mel today that I'm inclined to offer it along
     with the first two"

* emailed patches from Hugh Dickins <hughd@google.com>:
  mm: delete unnecessary and unsafe init_tlb_ubc()
  huge tmpfs: fix Committed_AS leak
  shmem: fix tmpfs to handle the huge= option properly

init_tlb_ubc() looked unnecessary to me: tlb_ubc is statically
initialized with zeroes in the init_task, and copied from parent to
child while it is quiescent in arch_dup_task_struct(); so I went to
delete it.

But inserted temporary debug WARN_ONs in place of init_tlb_ubc() to
check that it was always empty at that point, and found them firing:
because memcg reclaim can recurse into global reclaim (when allocating
biosets for swapout in my case), and arrive back at the init_tlb_ubc()
in shrink_node_memcg().

Resetting tlb_ubc.flush_required at that point is wrong: if the upper
level needs a deferred TLB flush, but the lower level turns out not to,
we miss a TLB flush.  But fortunately, that's the only part of the
protocol that does not nest: with the initialization removed, cpumask
collects bits from upper and lower levels, and flushes TLB when needed.

Fixes: 72b252ae ("mm: send one IPI per CPU to TLB flush all entries after unmapping pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: stable@vger.kernel.org # 4.3+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Under swapping load on huge tmpfs, /proc/meminfo's Committed_AS grows
bigger and bigger: just a cosmetic issue for most users, but disabling
for those who run without overcommit (/proc/sys/vm/overcommit_memory 2).

shmem_uncharge() was forgetting to unaccount __vm_enough_memory's
charge, and shmem_charge() was forgetting it on the filesystem-full
error path.

Fixes: 800d8c63 ("shmem: add huge pages support")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

shmem_get_unmapped_area() checks SHMEM_SB(sb)->huge incorrectly, which
leads to a reversed effect of "huge=" mount option.

Fix the check in shmem_get_unmapped_area().

Note, the default value of SHMEM_SB(sb)->huge remains as
SHMEM_HUGE_NEVER.  User will need to specify "huge=" option to enable
huge page mappings.
Reported-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull i2c fixes from Wolfram Sang:
 "Three driver bugfixes: fixing uninitialized memory pointers (eg20t),
  pm/clock imbalance (qup), and a wrongly set cached variable (pc954x)"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: qup: skip qup_i2c_suspend if the device is already runtime suspended
  i2c: mux: pca954x: retry updating the mux selection on failure
  i2c-eg20t: fix race between i2c init and interrupt enable

Pull input updates from Dmitry Torokhov:
 "Just a fix up for the firmware handling to the Silead driver (which is
  a new driver in this release)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: silead_gsl1680 - use "silead/" prefix for firmware loading
  Input: silead_gsl1680 - document firmware-name, fix implementation

Pull block fixes from Jens Axboe:
 "Three fixes, two regressions and one that poses a problem in blk-mq
  with the new nvmef code"

* 'for-linus' of git://git.kernel.dk/linux-block:
  blk-mq: skip unmapped queues in blk_mq_alloc_request_hctx
  nvme-rdma: only clear queue flags after successful connect
  blk-throttle: Extend slice if throttle group is not empty

On the v2 hierarchy, "cgroup.subtree_control" rejects controller
enables if the cgroup has processes in it.  The enforcement of this
logic assumes that the cgroup wouldn't have any css_sets associated
with it if there are no tasks in the cgroup, which is no longer true
since a79a908f ("cgroup: introduce cgroup namespaces").

When a cgroup namespace is created, it pins the css_set of the
creating task to use it as the root css_set of the namespace.  This
extra reference stays as long as the namespace is around and makes
"cgroup.subtree_control" think that the namespace root cgroup is not
empty even when it is and thus reject controller enables.

Fix it by making cgroup_subtree_control() walk and test emptiness of
each css_set instead of testing whether the list_head is empty.

While at it, update the comment of cgroup_task_count() to indicate
that the returned value may be higher than the number of tasks, which
has always been true due to temporary references and doesn't break
anything.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Evgeny Vereshchagin <evvers@ya.ru>
Cc: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Cc: Aditya Kali <adityakali@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: stable@vger.kernel.org # v4.6+
Fixes: a79a908f ("cgroup: introduce cgroup namespaces")
Link: https://github.com/systemd/systemd/pull/3589#issuecomment-249089541

Pull btrfs fixes from Chris Mason:
 "Josef fixed a problem when quotas are enabled with his latest ENOSPC
  rework, and Jeff added more checks into the subvol ioctls to avoid
  tripping up lookup_one_len"

* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: ensure that file descriptor used with subvol ioctls is a dir
  Btrfs: handle quota reserve failure properly