1. 07 Mar, 2022 22 commits
  2. 06 Mar, 2022 8 commits
    • Linus Torvalds's avatar
      Linux 5.17-rc7 · ffb217a1
      Linus Torvalds authored
      ffb217a1
    • Linus Torvalds's avatar
      Merge tag 'for-5.17-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux · 3ee65c0f
      Linus Torvalds authored
      Pull btrfs fixes from David Sterba:
       "A few more fixes for various problems that have user visible effects
        or seem to be urgent:
      
         - fix corruption when combining DIO and non-blocking io_uring over
           multiple extents (seen on MariaDB)
      
         - fix relocation crash due to premature return from commit
      
         - fix quota deadlock between rescan and qgroup removal
      
         - fix item data bounds checks in tree-checker (found on a fuzzed
           image)
      
         - fix fsync of prealloc extents after EOF
      
         - add missing run of delayed items after unlink during log replay
      
         - don't start relocation until snapshot drop is finished
      
         - fix reversed condition for subpage writers locking
      
         - fix warning on page error"
      
      * tag 'for-5.17-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
        btrfs: fallback to blocking mode when doing async dio over multiple extents
        btrfs: add missing run of delayed items after unlink during log replay
        btrfs: qgroup: fix deadlock between rescan worker and remove qgroup
        btrfs: fix relocation crash due to premature return from btrfs_commit_transaction()
        btrfs: do not start relocation until in progress drops are done
        btrfs: tree-checker: use u64 for item data end to avoid overflow
        btrfs: do not WARN_ON() if we have PageError set
        btrfs: fix lost prealloc extents beyond eof after full fsync
        btrfs: subpage: fix a wrong check on subpage->writers
      3ee65c0f
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · f81664f7
      Linus Torvalds authored
      Pull kvm fixes from Paolo Bonzini:
       "x86 guest:
      
         - Tweaks to the paravirtualization code, to avoid using them when
           they're pointless or harmful
      
        x86 host:
      
         - Fix for SRCU lockdep splat
      
         - Brown paper bag fix for the propagation of errno"
      
      * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
        KVM: x86: pull kvm->srcu read-side to kvm_arch_vcpu_ioctl_run
        KVM: x86/mmu: Passing up the error state of mmu_alloc_shadow_roots()
        KVM: x86: Yield to IPI target vCPU only if it is busy
        x86/kvmclock: Fix Hyper-V Isolated VM's boot issue when vCPUs > 64
        x86/kvm: Don't waste memory if kvmclock is disabled
        x86/kvm: Don't use PV TLB/yield when mwait is advertised
      f81664f7
    • Linus Torvalds's avatar
      Merge tag 'powerpc-5.17-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · 9bdeaca1
      Linus Torvalds authored
      Pull powerpc fix from Michael Ellerman:
       "Fix build failure when CONFIG_PPC_64S_HASH_MMU is not set.
      
        Thanks to Murilo Opsfelder Araujo, and Erhard F"
      
      * tag 'powerpc-5.17-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
        powerpc/64s: Fix build failure when CONFIG_PPC_64S_HASH_MMU is not set
      9bdeaca1
    • Linus Torvalds's avatar
      Merge tag 'trace-v5.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace · f40a33f5
      Linus Torvalds authored
      Pull tracing fixes from Steven Rostedt:
      
       - Fix sorting on old "cpu" value in histograms
      
       - Fix return value of __setup() boot parameter handlers
      
      * tag 'trace-v5.17-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
        tracing: Fix return value of __setup handlers
        tracing/histogram: Fix sorting on old "cpu" value
      f40a33f5
    • Jens Axboe's avatar
      Merge branch 'for-next' of... · a7637069
      Jens Axboe authored
      Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/colyli/linux-bcache into for-5.18/drivers
      
      Pull bcache updates from Coly:
      
      "We have 2 patches for Linux v5.18, both of them are from Mingzhe Zou.
       The first patch improves bcache initialization speed by avoid
       unnecessary cost of cache consistency, the second one fixes a potential
       NULL pointer deference in bcache initialization time."
      
      * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/colyli/linux-bcache:
        bcache: fixup multiple threads crash
        bcache: fixup bcache_dev_sectors_dirty_add() multithreaded CPU false sharing
      a7637069
    • Mingzhe Zou's avatar
      bcache: fixup multiple threads crash · 887554ab
      Mingzhe Zou authored
      When multiple threads to check btree nodes in parallel, the main
      thread wait for all threads to stop or CACHE_SET_IO_DISABLE flag:
      
      wait_event_interruptible(check_state->wait,
                               atomic_read(&check_state->started) == 0 ||
                               test_bit(CACHE_SET_IO_DISABLE, &c->flags));
      
      However, the bch_btree_node_read and bch_btree_node_read_done
      maybe call bch_cache_set_error, then the CACHE_SET_IO_DISABLE
      will be set. If the flag already set, the main thread return
      error. At the same time, maybe some threads still running and
      read NULL pointer, the kernel will crash.
      
      This patch change the event wait condition, the main thread must
      wait for all threads to stop.
      
      Fixes: 8e710227 ("bcache: make bch_btree_check() to be multithreaded")
      Signed-off-by: default avatarMingzhe Zou <mingzhe.zou@easystack.cn>
      Cc: stable@vger.kernel.org # v5.7+
      Signed-off-by: default avatarColy Li <colyli@suse.de>
      887554ab
    • Mingzhe Zou's avatar
      bcache: fixup bcache_dev_sectors_dirty_add() multithreaded CPU false sharing · 7b1002f7
      Mingzhe Zou authored
      When attaching a cached device (a.k.a backing device) to a cache
      device, bch_sectors_dirty_init() is called to count dirty sectors
      and stripes (see what bcache_dev_sectors_dirty_add() does) on the
      cache device.
      
      When bcache_dev_sectors_dirty_add() is called, set_bit(stripe,
      d->full_dirty_stripes) or clear_bit(stripe, d->full_dirty_stripes)
      operation will always be performed. In full_dirty_stripes, each 1bit
      represents stripe_size (8192) sectors (512B), so 1bit=4MB (8192*512),
      and each CPU cache line=64B=512bit=2048MB. When 20 threads process
      a cached disk with 100G dirty data, a single thread processes about
      23M at a time, and 20 threads total 460M. These full_dirty_stripes
      bits corresponding to the 460M data is likely to fall in the same CPU
      cache line. When one of these threads performs a set_bit or clear_bit
      operation, the same CPU cache line of other threads will become invalid
      and must read the full_dirty_stripes from the main memory again. Compared
      with single thread, the time of a bcache_dev_sectors_dirty_add()
      call is increased by about 50 times in our test (100G dirty data,
      20 threads, bcache_dev_sectors_dirty_add() is called more than
      20 million times).
      
      This patch tries to test_bit before set_bit or clear_bit operation.
      Therefore, a lot of force set and clear operations will be avoided,
      and most of bcache_dev_sectors_dirty_add() calls will only read CPU
      cache line.
      Signed-off-by: default avatarMingzhe Zou <mingzhe.zou@easystack.cn>
      Signed-off-by: default avatarColy Li <colyli@suse.de>
      7b1002f7
  3. 05 Mar, 2022 10 commits
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input · dcde98da
      Linus Torvalds authored
      Pull input updates from Dmitry Torokhov:
      
       - a fixup for Goodix touchscreen driver allowing it to work on certain
         Cherry Trail devices
      
       - a fix for imbalanced enable/disable regulator in Elam touchpad driver
         that became apparent when used with Asus TF103C 2-in-1 dock
      
       - a couple new input keycodes used on newer keyboards
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
        HID: add mapping for KEY_ALL_APPLICATIONS
        HID: add mapping for KEY_DICTATE
        Input: elan_i2c - fix regulator enable count imbalance after suspend/resume
        Input: elan_i2c - move regulator_[en|dis]able() out of elan_[en|dis]able_power()
        Input: goodix - workaround Cherry Trail devices with a bogus ACPI Interrupt() resource
        Input: goodix - use the new soc_intel_is_byt() helper
        Input: samsung-keypad - properly state IOMEM dependency
      dcde98da
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · 0014404f
      Linus Torvalds authored
      Merge misc fixes from Andrew Morton:
       "8 patches.
      
        Subsystems affected by this patch series: mm (hugetlb, pagemap, and
        userfaultfd), memfd, selftests, and kconfig"
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>:
        configs/debug: set CONFIG_DEBUG_INFO=y properly
        proc: fix documentation and description of pagemap
        kselftest/vm: fix tests build with old libc
        memfd: fix F_SEAL_WRITE after shmem huge page allocated
        mm: fix use-after-free when anon vma name is used after vma is freed
        mm: prevent vm_area_struct::anon_name refcount saturation
        mm: refactor vm_area_struct::anon_vma_name usage code
        selftests/vm: cleanup hugetlb file after mremap test
      0014404f
    • Linus Torvalds's avatar
      Merge tag 's390-5.17-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux · f9026e19
      Linus Torvalds authored
      Pull s390 fixes from Vasily Gorbik:
      
       - Fix HAVE_DYNAMIC_FTRACE_WITH_ARGS implementation by providing correct
         switching between ftrace_caller/ftrace_regs_caller and supplying
         pt_regs only when ftrace_regs_caller is activated.
      
       - Fix exception table sorting.
      
       - Fix breakage of kdump tooling by preserving metadata it cannot
         function without.
      
      * tag 's390-5.17-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
        s390/extable: fix exception table sorting
        s390/ftrace: fix arch_ftrace_get_regs implementation
        s390/ftrace: fix ftrace_caller/ftrace_regs_caller generation
        s390/setup: preserve memory at OLDMEM_BASE and OLDMEM_SIZE
      f9026e19
    • Qian Cai's avatar
      configs/debug: set CONFIG_DEBUG_INFO=y properly · d1eff16d
      Qian Cai authored
      CONFIG_DEBUG_INFO can't be set by user directly, so set
      CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y instead.
      
      Otherwise, we end up with no debuginfo in vmlinux which is a big no-no
      for kernel debugging.
      
      Link: https://lkml.kernel.org/r/20220301202920.18488-1-quic_qiancai@quicinc.comSigned-off-by: default avatarQian Cai <quic_qiancai@quicinc.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d1eff16d
    • Yun Zhou's avatar
      proc: fix documentation and description of pagemap · dd21bfa4
      Yun Zhou authored
      Since bit 57 was exported for uffd-wp write-protected (commit
      fb8e37f3: "mm/pagemap: export uffd-wp protection information"),
      fixing it can reduce some unnecessary confusion.
      
      Link: https://lkml.kernel.org/r/20220301044538.3042713-1-yun.zhou@windriver.com
      Fixes: fb8e37f3 ("mm/pagemap: export uffd-wp protection information")
      Signed-off-by: default avatarYun Zhou <yun.zhou@windriver.com>
      Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Tiberiu A Georgescu <tiberiu.georgescu@nutanix.com>
      Cc: Florian Schmidt <florian.schmidt@nutanix.com>
      Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
      Cc: SeongJae Park <sj@kernel.org>
      Cc: Yang Shi <shy828301@gmail.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: Axel Rasmussen <axelrasmussen@google.com>
      Cc: Miaohe Lin <linmiaohe@huawei.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Colin Cross <ccross@google.com>
      Cc: Alistair Popple <apopple@nvidia.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dd21bfa4
    • Chengming Zhou's avatar
      kselftest/vm: fix tests build with old libc · b773827e
      Chengming Zhou authored
      The error message when I build vm tests on debian10 (GLIBC 2.28):
      
          userfaultfd.c: In function `userfaultfd_pagemap_test':
          userfaultfd.c:1393:37: error: `MADV_PAGEOUT' undeclared (first use
          in this function); did you mean `MADV_RANDOM'?
            if (madvise(area_dst, test_pgsize, MADV_PAGEOUT))
                                               ^~~~~~~~~~~~
                                               MADV_RANDOM
      
      This patch includes these newer definitions from UAPI linux/mman.h, is
      useful to fix tests build on systems without these definitions in glibc
      sys/mman.h.
      
      Link: https://lkml.kernel.org/r/20220227055330.43087-2-zhouchengming@bytedance.comSigned-off-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
      Reviewed-by: default avatarShuah Khan <skhan@linuxfoundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b773827e
    • Hugh Dickins's avatar
      memfd: fix F_SEAL_WRITE after shmem huge page allocated · f2b277c4
      Hugh Dickins authored
      Wangyong reports: after enabling tmpfs filesystem to support transparent
      hugepage with the following command:
      
        echo always > /sys/kernel/mm/transparent_hugepage/shmem_enabled
      
      the docker program tries to add F_SEAL_WRITE through the following
      command, but it fails unexpectedly with errno EBUSY:
      
        fcntl(5, F_ADD_SEALS, F_SEAL_WRITE) = -1.
      
      That is because memfd_tag_pins() and memfd_wait_for_pins() were never
      updated for shmem huge pages: checking page_mapcount() against
      page_count() is hopeless on THP subpages - they need to check
      total_mapcount() against page_count() on THP heads only.
      
      Make memfd_tag_pins() (compared > 1) as strict as memfd_wait_for_pins()
      (compared != 1): either can be justified, but given the non-atomic
      total_mapcount() calculation, it is better now to be strict.  Bear in
      mind that total_mapcount() itself scans all of the THP subpages, when
      choosing to take an XA_CHECK_SCHED latency break.
      
      Also fix the unlikely xa_is_value() case in memfd_wait_for_pins(): if a
      page has been swapped out since memfd_tag_pins(), then its refcount must
      have fallen, and so it can safely be untagged.
      
      Link: https://lkml.kernel.org/r/a4f79248-df75-2c8c-3df-ba3317ccb5da@google.comSigned-off-by: default avatarHugh Dickins <hughd@google.com>
      Reported-by: default avatarZeal Robot <zealci@zte.com.cn>
      Reported-by: default avatarwangyong <wang.yong12@zte.com.cn>
      Cc: Mike Kravetz <mike.kravetz@oracle.com>
      Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
      Cc: CGEL ZTE <cgel.zte@gmail.com>
      Cc: Kirill A. Shutemov <kirill@shutemov.name>
      Cc: Song Liu <songliubraving@fb.com>
      Cc: Yang Yang <yang.yang29@zte.com.cn>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f2b277c4
    • Suren Baghdasaryan's avatar
      mm: fix use-after-free when anon vma name is used after vma is freed · 942341dc
      Suren Baghdasaryan authored
      When adjacent vmas are being merged it can result in the vma that was
      originally passed to madvise_update_vma being destroyed.  In the current
      implementation, the name parameter passed to madvise_update_vma points
      directly to vma->anon_name and it is used after the call to vma_merge.
      In the cases when vma_merge merges the original vma and destroys it,
      this might result in UAF.  For that the original vma would have to hold
      the anon_vma_name with the last reference.  The following vma would need
      to contain a different anon_vma_name object with the same string.  Such
      scenario is shown below:
      
      madvise_vma_behavior(vma)
        madvise_update_vma(vma, ..., anon_name == vma->anon_name)
          vma_merge(vma)
            __vma_adjust(vma) <-- merges vma with adjacent one
              vm_area_free(vma) <-- frees the original vma
          replace_vma_anon_name(anon_name) <-- UAF of vma->anon_name
      
      Fix this by raising the name refcount and stabilizing it.
      
      Link: https://lkml.kernel.org/r/20220224231834.1481408-3-surenb@google.com
      Link: https://lkml.kernel.org/r/20220223153613.835563-3-surenb@google.com
      Fixes: 9a10064f ("mm: add a field to store names for private anonymous memory")
      Signed-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
      Reported-by: syzbot+aa7b3d4b35f9dc46a366@syzkaller.appspotmail.com
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Cc: Alexey Gladkov <legion@kernel.org>
      Cc: Chris Hyser <chris.hyser@oracle.com>
      Cc: Christian Brauner <brauner@kernel.org>
      Cc: Colin Cross <ccross@google.com>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Peter Collingbourne <pcc@google.com>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sumit Semwal <sumit.semwal@linaro.org>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      942341dc
    • Suren Baghdasaryan's avatar
      mm: prevent vm_area_struct::anon_name refcount saturation · 96403e11
      Suren Baghdasaryan authored
      A deep process chain with many vmas could grow really high.  With
      default sysctl_max_map_count (64k) and default pid_max (32k) the max
      number of vmas in the system is 2147450880 and the refcounter has
      headroom of 1073774592 before it reaches REFCOUNT_SATURATED
      (3221225472).
      
      Therefore it's unlikely that an anonymous name refcounter will overflow
      with these defaults.  Currently the max for pid_max is PID_MAX_LIMIT
      (4194304) and for sysctl_max_map_count it's INT_MAX (2147483647).  In
      this configuration anon_vma_name refcount overflow becomes theoretically
      possible (that still require heavy sharing of that anon_vma_name between
      processes).
      
      kref refcounting interface used in anon_vma_name structure will detect a
      counter overflow when it reaches REFCOUNT_SATURATED value but will only
      generate a warning and freeze the ref counter.  This would lead to the
      refcounted object never being freed.  A determined attacker could leak
      memory like that but it would be rather expensive and inefficient way to
      do so.
      
      To ensure anon_vma_name refcount does not overflow, stop anon_vma_name
      sharing when the refcount reaches REFCOUNT_MAX (2147483647), which still
      leaves INT_MAX/2 (1073741823) values before the counter reaches
      REFCOUNT_SATURATED.  This should provide enough headroom for raising the
      refcounts temporarily.
      
      Link: https://lkml.kernel.org/r/20220223153613.835563-2-surenb@google.comSigned-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
      Suggested-by: default avatarMichal Hocko <mhocko@suse.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Cc: Alexey Gladkov <legion@kernel.org>
      Cc: Chris Hyser <chris.hyser@oracle.com>
      Cc: Christian Brauner <brauner@kernel.org>
      Cc: Colin Cross <ccross@google.com>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Peter Collingbourne <pcc@google.com>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Sumit Semwal <sumit.semwal@linaro.org>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      96403e11
    • Suren Baghdasaryan's avatar
      mm: refactor vm_area_struct::anon_vma_name usage code · 5c26f6ac
      Suren Baghdasaryan authored
      Avoid mixing strings and their anon_vma_name referenced pointers by
      using struct anon_vma_name whenever possible.  This simplifies the code
      and allows easier sharing of anon_vma_name structures when they
      represent the same name.
      
      [surenb@google.com: fix comment]
      
      Link: https://lkml.kernel.org/r/20220223153613.835563-1-surenb@google.com
      Link: https://lkml.kernel.org/r/20220224231834.1481408-1-surenb@google.comSigned-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
      Suggested-by: default avatarMatthew Wilcox <willy@infradead.org>
      Suggested-by: default avatarMichal Hocko <mhocko@suse.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Cc: Colin Cross <ccross@google.com>
      Cc: Sumit Semwal <sumit.semwal@linaro.org>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Christian Brauner <brauner@kernel.org>
      Cc: Alexey Gladkov <legion@kernel.org>
      Cc: Sasha Levin <sashal@kernel.org>
      Cc: Chris Hyser <chris.hyser@oracle.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: Peter Collingbourne <pcc@google.com>
      Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
      Cc: David Hildenbrand <david@redhat.com>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5c26f6ac