KVM: x86: Fix APIC map calculation after re-enabling

Update arch.apic_base before triggering recalculate_apic_map. Otherwise
the recalculation will work against the previous state of the APIC and
will fail to build the correct map when an APIC is hardware-enabled
again.

This fixes a regression of 1e08ec4a13.

Cc: stable@vger.kernel.org
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
KVM: nVMX: Unconditionally uninit the MMU on nested vmexit

Three reasons for doing this: 1. arch.walk_mmu points to arch.mmu anyway
in case nested EPT wasn't in use. 2. this aligns VMX with SVM. But 3. is
most important: nested_cpu_has_ept(vmcs12) queries the VMCS page, and if
one guest VCPU manipulates the page of another VCPU in L2, we may be
fooled to skip over the nested_ept_uninit_mmu_context, leaving mmu in
nested state. That can crash the host later on if nested_ept_get_cr3 is
invoked while L1 already left vmxon and nested.current_vmcs12 became
NULL therefore.

Cc: stable@kernel.org
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
mm: munlock: fix a bug where THP tail page is encountered

Since commit ff6a6da60b89 ("mm: accelerate munlock() treatment of THP
pages") munlock skips tail pages of a munlocked THP page.  However, when
the head page already has PageMlocked unset, it will not skip the tail
pages.

Commit 7225522bb429 ("mm: munlock: batch non-THP page isolation and
munlock+putback using pagevec") has added a PageTransHuge() check which
contains VM_BUG_ON(PageTail(page)).  Sasha Levin found this triggered
using trinity, on the first tail page of a THP page without PageMlocked
flag.

This patch fixes the issue by skipping tail pages also in the case when
PageMlocked flag is unset.  There is still a possibility of race with
THP page split between clearing PageMlocked and determining how many
pages to skip.  The race might result in former tail pages not being
skipped, which is however no longer a bug, as during the skip the
PageTail flags are cleared.

However this race also affects correctness of NR_MLOCK accounting, which
is to be fixed in a separate patch.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: munlock: fix deadlock in __munlock_pagevec()

Commit 7225522bb429 ("mm: munlock: batch non-THP page isolation and
munlock+putback using pagevec" introduced __munlock_pagevec() to speed
up munlock by holding lru_lock over multiple isolated pages.  Pages that
fail to be isolated are put_page()d immediately, also within the lock.

This can lead to deadlock when __munlock_pagevec() becomes the holder of
the last page pin and put_page() leads to __page_cache_release() which
also locks lru_lock.  The deadlock has been observed by Sasha Levin
using trinity.

This patch avoids the deadlock by deferring put_page() operations until
lru_lock is released.  Another pagevec (which is also used by later
phases of the function is reused to gather the pages for put_page()
operation.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: 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>
mm: fix use-after-free in sys_remap_file_pages

remap_file_pages calls mmap_region, which may merge the VMA with other
existing VMAs, and free "vma".  This can lead to a use-after-free bug.
Avoid the bug by remembering vm_flags before calling mmap_region, and
not trying to dereference vma later.

Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: 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>
memcg: fix memcg_size() calculation

The mem_cgroup structure contains nr_node_ids pointers to
mem_cgroup_per_node objects, not the objects themselves.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: remove bogus warning in copy_huge_pmd()

Sasha Levin reported the following warning being triggered

  WARNING: CPU: 28 PID: 35287 at mm/huge_memory.c:887 copy_huge_pmd+0x145/ 0x3a0()
  Call Trace:
    copy_huge_pmd+0x145/0x3a0
    copy_page_range+0x3f2/0x560
    dup_mmap+0x2c9/0x3d0
    dup_mm+0xad/0x150
    copy_process+0xa68/0x12e0
    do_fork+0x96/0x270
    SyS_clone+0x16/0x20
    stub_clone+0x69/0x90

This warning was introduced by "mm: numa: Avoid unnecessary disruption
of NUMA hinting during migration" for paranoia reasons but the warning
is bogus.  I was thinking of parallel races between NUMA hinting faults
and forks but this warning would also be triggered by a parallel reclaim
splitting a THP during a fork.  Remote the bogus warning.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MAINTAINERS: set up proper record for Xilinx Zynq

Setup correct zynq entry.
 - Add missing cadence_ttc_timer maintainership
 - Add zynq wildcard
 - Add xilinx wildcard

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memory-failure.c: transfer page count from head page to tail page after split thp

Memory failures on thp tail pages cause kernel panic like below:

   mce: [Hardware Error]: Machine check events logged
   MCE exception done on CPU 7
   BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
   IP: [<ffffffff811b7cd1>] dequeue_hwpoisoned_huge_page+0x131/0x1e0
   PGD bae42067 PUD ba47d067 PMD 0
   Oops: 0000 [#1] SMP
  ...
   CPU: 7 PID: 128 Comm: kworker/7:2 Tainted: G   M       O 3.13.0-rc4-131217-1558-00003-g83b7df08e462 #25
  ...
   Call Trace:
     me_huge_page+0x3e/0x50
     memory_failure+0x4bb/0xc20
     mce_process_work+0x3e/0x70
     process_one_work+0x171/0x420
     worker_thread+0x11b/0x3a0
     ? manage_workers.isra.25+0x2b0/0x2b0
     kthread+0xe4/0x100
     ? kthread_create_on_node+0x190/0x190
     ret_from_fork+0x7c/0xb0
     ? kthread_create_on_node+0x190/0x190
  ...
   RIP   dequeue_hwpoisoned_huge_page+0x131/0x1e0
   CR2: 0000000000000058

The reasoning of this problem is shown below:
 - when we have a memory error on a thp tail page, the memory error
   handler grabs a refcount of the head page to keep the thp under us.
 - Before unmapping the error page from processes, we split the thp,
   where page refcounts of both of head/tail pages don't change.
 - Then we call try_to_unmap() over the error page (which was a tail
   page before). We didn't pin the error page to handle the memory error,
   this error page is freed and removed from LRU list.
 - We never have the error page on LRU list, so the first page state
   check returns "unknown page," then we move to the second check
   with the saved page flag.
 - The saved page flag have PG_tail set, so the second page state check
   returns "hugepage."
 - We call me_huge_page() for freed error page, then we hit the above panic.

The root cause is that we didn't move refcount from the head page to the
tail page after split thp.  So this patch suggests to do this.

This panic was introduced by commit 524fca1e73 ("HWPOISON: fix
misjudgement of page_action() for errors on mlocked pages").  Note that we
did have the same refcount problem before this commit, but it was just
ignored because we had only first page state check which returned "unknown
page." The commit changed the refcount problem from "doesn't work" to
"kernel panic."

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: <stable@vger.kernel.org>	[3.9+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/dma/ioat/dma.c: check DMA mapping error in ioat_dma_self_test()

Check DMA mapping return values in function ioat_dma_self_test() to get
rid of following warning message.

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 1203 at lib/dma-debug.c:937 check_unmap+0x4c0/0x9a0()
  ioatdma 0000:00:04.0: DMA-API: device driver failed to check map error[device address=0x000000085191b000] [size=2000 bytes] [mapped as single]
  Modules linked in: ioatdma(+) mac_hid wmi acpi_pad lp parport hidd_generic usbhid hid ixgbe isci dca libsas ahci ptp libahci scsi_transport_sas meegaraid_sas pps_core mdio
  CPU: 0 PID: 1203 Comm: systemd-udevd Not tainted 3.13.0-rc4+ #8
  Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRIVTIIN1.86B.0044.L09.1311181644 11/18/2013
  Call Trace:
    dump_stack+0x4d/0x66
    warn_slowpath_common+0x7d/0xa0
    warn_slowpath_fmt+0x4c/0x50
    check_unmap+0x4c0/0x9a0
    debug_dma_unmap_page+0x81/0x90
    ioat_dma_self_test+0x3d2/0x680 [ioatdma]
    ioat3_dma_self_test+0x12/0x30 [ioatdma]
    ioat_probe+0xf4/0x110 [ioatdma]
    ioat3_dma_probe+0x268/0x410 [ioatdma]
    ioat_pci_probe+0x122/0x1b0 [ioatdma]
    local_pci_probe+0x45/0xa0
    pci_device_probe+0xd9/0x130
    driver_probe_device+0x171/0x490
    __driver_attach+0x93/0xa0
    bus_for_each_dev+0x6b/0xb0
    driver_attach+0x1e/0x20
    bus_add_driver+0x1f8/0x2b0
    driver_register+0x81/0x110
    __pci_register_driver+0x60/0x70
    ioat_init_module+0x89/0x1000 [ioatdma]
    do_one_initcall+0xe2/0x250
    load_module+0x2313/0x2a00
    SyS_init_module+0xd9/0x130
    system_call_fastpath+0x1a/0x1f
  ---[ end trace 990c591681d27c31 ]---
  Mapped at:
    debug_dma_map_page+0xbe/0x180
    ioat_dma_self_test+0x1ab/0x680 [ioatdma]
    ioat3_dma_self_test+0x12/0x30 [ioatdma]
    ioat_probe+0xf4/0x110 [ioatdma]
    ioat3_dma_probe+0x268/0x410 [ioatdma]

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sh: add EXPORT_SYMBOL(min_low_pfn) and EXPORT_SYMBOL(max_low_pfn) to sh_ksyms_32.c

Min_low_pfn and max_low_pfn were used in pfn_valid macro if defined
CONFIG_FLATMEM.  When the functions that use the pfn_valid is used in
driver module, max_low_pfn and min_low_pfn is to undefined, and fail to
build.

  ERROR: "min_low_pfn" [drivers/block/aoe/aoe.ko] undefined!
  ERROR: "max_low_pfn" [drivers/block/aoe/aoe.ko] undefined!
  make[2]: *** [__modpost] Error 1
  make[1]: *** [modules] Error 2

This patch fix this problem.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
epoll: do not take the nested ep->mtx on EPOLL_CTL_DEL

The EPOLL_CTL_DEL path of epoll contains a classic, ab-ba deadlock.
That is, epoll_ctl(a, EPOLL_CTL_DEL, b, x), will deadlock with
epoll_ctl(b, EPOLL_CTL_DEL, a, x).  The deadlock was introduced with
commmit 67347fe4e632 ("epoll: do not take global 'epmutex' for simple
topologies").

The acquistion of the ep->mtx for the destination 'ep' was added such
that a concurrent EPOLL_CTL_ADD operation would see the correct state of
the ep (Specifically, the check for '!list_empty(&f.file->f_ep_links')

However, by simply not acquiring the lock, we do not serialize behind
the ep->mtx from the add path, and thus may perform a full path check
when if we had waited a little longer it may not have been necessary.
However, this is a transient state, and performing the full loop
checking in this case is not harmful.

The important point is that we wouldn't miss doing the full loop
checking when required, since EPOLL_CTL_ADD always locks any 'ep's that
its operating upon.  The reason we don't need to do lock ordering in the
add path, is that we are already are holding the global 'epmutex'
whenever we do the double lock.  Further, the original posting of this
patch, which was tested for the intended performance gains, did not
perform this additional locking.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: Nathan Zimmer <nzimmer@sgi.com>
Cc: Eric Wong <normalperson@yhbt.net>
Cc: Nelson Elhage <nelhage@nelhage.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'akpm' (incoming from Andrew)

Merge patches from Andrew Morton:
 "Ten fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  epoll: do not take the nested ep->mtx on EPOLL_CTL_DEL
  sh: add EXPORT_SYMBOL(min_low_pfn) and EXPORT_SYMBOL(max_low_pfn) to sh_ksyms_32.c
  drivers/dma/ioat/dma.c: check DMA mapping error in ioat_dma_self_test()
  mm/memory-failure.c: transfer page count from head page to tail page after split thp
  MAINTAINERS: set up proper record for Xilinx Zynq
  mm: remove bogus warning in copy_huge_pmd()
  memcg: fix memcg_size() calculation
  mm: fix use-after-free in sys_remap_file_pages
  mm: munlock: fix deadlock in __munlock_pagevec()
  mm: munlock: fix a bug where THP tail page is encountered
Merge git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm bugfixes from Marcelo Tosatti.

* git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: nVMX: Unconditionally uninit the MMU on nested vmexit
  KVM: x86: Fix APIC map calculation after re-enabling