1. 01 Oct, 2018 4 commits
    • Miklos Szeredi's avatar
      fuse: use mtime for readdir cache verification · 7118883b
      Miklos Szeredi authored
      
      
      Store the modification time of the directory in the cache, obtained before
      starting to fill the cache.
      
      When reading the cache, verify that the directory hasn't changed, by
      checking if current modification time is the same as the one stored in the
      cache.
      
      This only needs to be done when the current file position is at the
      beginning of the directory, as mandated by POSIX.
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
      7118883b
    • Miklos Szeredi's avatar
      fuse: add readdir cache version · 3494927e
      Miklos Szeredi authored
      
      
      Allow the cache to be invalidated when page(s) have gone missing.  In this
      case increment the version of the cache and reset to an empty state.
      
      Add a version number to the directory stream in struct fuse_file as well,
      indicating the version of the cache it's supposed to be reading.  If the
      cache version doesn't match the stream's version, then reset the stream to
      the beginning of the cache.
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
      3494927e
    • Miklos Szeredi's avatar
      fuse: allow using readdir cache · 5d7bc7e8
      Miklos Szeredi authored
      
      
      The cache is only used if it's completed, not while it's still being
      filled; this constraint could be lifted later, if it turns out to be
      useful.
      
      Introduce state in struct fuse_file that indicates the position within the
      cache.  After a seek, reset the position to the beginning of the cache and
      search the cache for the current position.  If the current position is not
      found in the cache, then fall back to uncached readdir.
      
      It can also happen that page(s) disappear from the cache, in which case we
      must also fall back to uncached readdir.
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
      5d7bc7e8
    • Miklos Szeredi's avatar
      fuse: allow caching readdir · 69e34551
      Miklos Szeredi authored
      
      
      This patch just adds the cache filling functions, which are invoked if
      FOPEN_CACHE_DIR flag is set in the OPENDIR reply.
      
      Cache reading and cache invalidation are added by subsequent patches.
      
      The directory cache uses the page cache.  Directory entries are packed into
      a page in the same format as in the READDIR reply.  A page only contains
      whole entries, the space at the end of the page is cleared.  The page is
      locked while being modified.
      
      Multiple parallel readdirs on the same directory can fill the cache; the
      only constraint is that continuity must be maintained (d_off of last entry
      points to position of current entry).
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
      69e34551
  2. 28 Sep, 2018 16 commits
  3. 23 Sep, 2018 7 commits
  4. 22 Sep, 2018 1 commit
    • Omar Sandoval's avatar
      block: use nanosecond resolution for iostat · b57e99b4
      Omar Sandoval authored
      Klaus Kusche reported that the I/O busy time in /proc/diskstats was not
      updating properly on 4.18. This is because we started using ktime to
      track elapsed time, and we convert nanoseconds to jiffies when we update
      the partition counter. However, this gets rounded down, so any I/Os that
      take less than a jiffy are not accounted for. Previously in this case,
      the value of jiffies would sometimes increment while we were doing I/O,
      so at least some I/Os were accounted for.
      
      Let's convert the stats to use nanoseconds internally. We still report
      milliseconds as before, now more accurately than ever. The value is
      still truncated to 32 bits for backwards compatibility.
      
      Fixes: 522a7775
      
       ("block: consolidate struct request timestamp fields")
      Cc: stable@vger.kernel.org
      Reported-by: default avatarKlaus Kusche <klaus.kusche@computerix.info>
      Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      b57e99b4
  5. 21 Sep, 2018 5 commits
    • Greg Kroah-Hartman's avatar
      Merge tag 'pinctrl-v4.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl · 10dc890d
      Greg Kroah-Hartman authored
      Linus writes:
        "Pin control fixes for v4.19:
         - Two fixes for the Intel pin controllers than cause
           problems on laptops."
      
      * tag 'pinctrl-v4.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
        pinctrl: intel: Do pin translation in other GPIO operations as well
        pinctrl: cannonlake: Fix gpio base for GPP-E
      10dc890d
    • Greg Kroah-Hartman's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · a27fb6d9
      Greg Kroah-Hartman authored
      Paolo writes:
        "It's mostly small bugfixes and cleanups, mostly around x86 nested
         virtualization.  One important change, not related to nested
         virtualization, is that the ability for the guest kernel to trap
         CPUID instructions (in Linux that's the ARCH_SET_CPUID arch_prctl) is
         now masked by default.  This is because the feature is detected
         through an MSR; a very bad idea that Intel seems to like more and
         more.  Some applications choke if the other fields of that MSR are
         not initialized as on real hardware, hence we have to disable the
         whole MSR by default, as was the case before Linux 4.12."
      
      * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (23 commits)
        KVM: nVMX: Fix bad cleanup on error of get/set nested state IOCTLs
        kvm: selftests: Add platform_info_test
        KVM: x86: Control guest reads of MSR_PLATFORM_INFO
        KVM: x86: Turbo bits in MSR_PLATFORM_INFO
        nVMX x86: Check VPID value on vmentry of L2 guests
        nVMX x86: check posted-interrupt descriptor addresss on vmentry of L2
        KVM: nVMX: Wake blocked vCPU in guest-mode if pending interrupt in virtual APICv
        KVM: VMX: check nested state and CR4.VMXE against SMM
        kvm: x86: make kvm_{load|put}_guest_fpu() static
        x86/hyper-v: rename ipi_arg_{ex,non_ex} structures
        KVM: VMX: use preemption timer to force immediate VMExit
        KVM: VMX: modify preemption timer bit only when arming timer
        KVM: VMX: immediately mark preemption timer expired only for zero value
        KVM: SVM: Switch to bitmap_zalloc()
        KVM/MMU: Fix comment in walk_shadow_page_lockless_end()
        kvm: selftests: use -pthread instead of -lpthread
        KVM: x86: don't reset root in kvm_mmu_setup()
        kvm: mmu: Don't read PDPTEs when paging is not enabled
        x86/kvm/lapic: always disable MMIO interface in x2APIC mode
        KVM: s390: Make huge pages unavailable in ucontrol VMs
        ...
      a27fb6d9
    • Greg Kroah-Hartman's avatar
      Merge tag 'upstream-4.19-rc4' of git://git.infradead.org/linux-ubifs · 0eba8697
      Greg Kroah-Hartman authored
      Richard writes:
        "This pull request contains fixes for UBIFS:
         - A wrong UBIFS assertion in mount code
         - Fix for a NULL pointer deref in mount code
         - Revert of a bad fix for xattrs"
      
      * tag 'upstream-4.19-rc4' of git://git.infradead.org/linux-ubifs:
        Revert "ubifs: xattr: Don't operate on deleted inodes"
        ubifs: drop false positive assertion
        ubifs: Check for name being NULL while mounting
      0eba8697
    • Greg Kroah-Hartman's avatar
      Merge tag 'for-linus-20180920' of git://git.kernel.dk/linux-block · 211b100a
      Greg Kroah-Hartman authored
      Jens writes:
        "Storage fixes for 4.19-rc5
      
        - Fix for leaking kernel pointer in floppy ioctl (Andy Whitcroft)
      
        - NVMe pull request from Christoph, and a single ANA log page fix
          (Hannes)
      
        - Regression fix for libata qd32 support, where we trigger an illegal
          active command transition. This fixes a CD-ROM detection issue that
          was reported, but could also trigger premature completion of the
          internal tag (me)"
      
      * tag 'for-linus-20180920' of git://git.kernel.dk/linux-block:
        floppy: Do not copy a kernel pointer to user memory in FDGETPRM ioctl
        libata: mask swap internal and hardware tag
        nvme: count all ANA groups for ANA Log page
      211b100a
    • Greg Kroah-Hartman's avatar
      Merge tag 'drm-fixes-2018-09-21' of git://anongit.freedesktop.org/drm/drm · a38fd7d8
      Greg Kroah-Hartman authored
      David writes:
        "drm fixes for 4.19-rc5:
      
         - core: fix debugfs for atomic, fix the check for atomic for
           non-modesetting drivers
         - amdgpu: adds a new PCI id, some kfd fixes and a sdma fix
         - i915: a bunch of GVT fixes.
         - vc4: scaling fix
         - vmwgfx: modesetting fixes and a old buffer eviction fix
         - udl: framebuffer destruction fix
         - sun4i: disable on R40 fix until next kernel
         - pl111: NULL termination on table fix"
      
      * tag 'drm-fixes-2018-09-21' of git://anongit.freedesktop.org/drm/drm: (21 commits)
        drm/amdkfd: Fix ATS capablity was not reported correctly on some APUs
        drm/amdkfd: Change the control stack MTYPE from UC to NC on GFX9
        drm/amdgpu: Fix SDMA HQD destroy error on gfx_v7
        drm/vmwgfx: Fix buffer object eviction
        drm/vmwgfx: Don't impose STDU limits on framebuffer size
        drm/vmwgfx: limit mode size for all display unit to texture_max
        drm/vmwgfx: limit screen size to stdu_max during check_modeset
        drm/vmwgfx: don't check for old_crtc_state enable status
        drm/amdgpu: add new polaris pci id
        drm: sun4i: drop second PLL from A64 HDMI PHY
        drm: fix drm_drv_uses_atomic_modeset on non modesetting drivers.
        drm/i915/gvt: clear ggtt entries when destroy vgpu
        drm/i915/gvt: request srcu_read_lock before checking if one gfn is valid
        drm/i915/gvt: Add GEN9_CLKGATE_DIS_4 to default BXT mmio handler
        drm/i915/gvt: Init PHY related registers for BXT
        drm/atomic: Use drm_drv_uses_atomic_modeset() for debugfs creation
        drm/fb-helper: Remove set but not used variable 'connector_funcs'
        drm: udl: Destroy framebuffer only if it was initialized
        drm/sun4i: Remove R40 display pipeline compatibles
        drm/pl111: Make sure of_device_id tables are NULL terminated
        ...
      a38fd7d8
  6. 20 Sep, 2018 7 commits
    • Dave Airlie's avatar
      Merge branch 'drm-fixes-4.19' of git://people.freedesktop.org/~agd5f/linux into drm-fixes · 4fcb7f8b
      Dave Airlie authored
      
      
      A few fixes for 4.19:
      - Add a new polaris pci id
      - KFD fixes for raven and gfx7
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      From: Alex Deucher <alexdeucher@gmail.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/20180920155850.5455-1-alexander.deucher@amd.com
      4fcb7f8b
    • Dave Airlie's avatar
      Merge branch 'vmwgfx-fixes-4.19' of git://people.freedesktop.org/~thomash/linux into drm-fixes · 618cc151
      Dave Airlie authored
      
      
      A couple of modesetting fixes and a fix for a long-standing buffer-eviction
      problem cc'd stable.
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      From: Thomas Hellstrom <thellstrom@vmware.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/20180920063935.35492-1-thellstrom@vmware.com
      618cc151
    • Feng Tang's avatar
      x86/mm: Expand static page table for fixmap space · 05ab1d8a
      Feng Tang authored
      We met a kernel panic when enabling earlycon, which is due to the fixmap
      address of earlycon is not statically setup.
      
      Currently the static fixmap setup in head_64.S only covers 2M virtual
      address space, while it actually could be in 4M space with different
      kernel configurations, e.g. when VSYSCALL emulation is disabled.
      
      So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2,
      and add a build time check to ensure that the fixmap is covered by the
      initial static page tables.
      
      Fixes: 1ad83c85
      
       ("x86_64,vsyscall: Make vsyscall emulation configurable")
      Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarFeng Tang <feng.tang@intel.com>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Tested-by: default avatarkernel test robot <rong.a.chen@intel.com>
      Reviewed-by: Juergen Gross <jgross@suse.com> (Xen parts)
      Cc: H Peter Anvin <hpa@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Andy Lutomirsky <luto@kernel.org>
      Cc: stable@vger.kernel.org
      Link: https://lkml.kernel.org/r/20180920025828.23699-1-feng.tang@intel.com
      05ab1d8a
    • Junxiao Bi's avatar
      ocfs2: fix ocfs2 read block panic · 234b69e3
      Junxiao Bi authored
      While reading block, it is possible that io error return due to underlying
      storage issue, in this case, BH_NeedsValidate was left in the buffer head.
      Then when reading the very block next time, if it was already linked into
      journal, that will trigger the following panic.
      
      [203748.702517] kernel BUG at fs/ocfs2/buffer_head_io.c:342!
      [203748.702533] invalid opcode: 0000 [#1] SMP
      [203748.702561] Modules linked in: ocfs2 ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager ocfs2_stackglue configfs sunrpc dm_switch dm_queue_length dm_multipath bonding be2iscsi iscsi_boot_sysfs bnx2i cnic uio cxgb4i iw_cxgb4 cxgb4 cxgb3i libcxgbi iw_cxgb3 cxgb3 mdio ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr ipv6 iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ipmi_devintf iTCO_wdt iTCO_vendor_support dcdbas ipmi_ssif i2c_core ipmi_si ipmi_msghandler acpi_pad pcspkr sb_edac edac_core lpc_ich mfd_core shpchp sg tg3 ptp pps_core ext4 jbd2 mbcache2 sr_mod cdrom sd_mod ahci libahci megaraid_sas wmi dm_mirror dm_region_hash dm_log dm_mod
      [203748.703024] CPU: 7 PID: 38369 Comm: touch Not tainted 4.1.12-124.18.6.el6uek.x86_64 #2
      [203748.703045] Hardware name: Dell Inc. PowerEdge R620/0PXXHP, BIOS 2.5.2 01/28/2015
      [203748.703067] task: ffff880768139c00 ti: ffff88006ff48000 task.ti: ffff88006ff48000
      [203748.703088] RIP: 0010:[<ffffffffa05e9f09>]  [<ffffffffa05e9f09>] ocfs2_read_blocks+0x669/0x7f0 [ocfs2]
      [203748.703130] RSP: 0018:ffff88006ff4b818  EFLAGS: 00010206
      [203748.703389] RAX: 0000000008620029 RBX: ffff88006ff4b910 RCX: 0000000000000000
      [203748.703885] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00000000023079fe
      [203748.704382] RBP: ffff88006ff4b8d8 R08: 0000000000000000 R09: ffff8807578c25b0
      [203748.704877] R10: 000000000f637376 R11: 000000003030322e R12: 0000000000000000
      [203748.705373] R13: ffff88006ff4b910 R14: ffff880732fe38f0 R15: 0000000000000000
      [203748.705871] FS:  00007f401992c700(0000) GS:ffff880bfebc0000(0000) knlGS:0000000000000000
      [203748.706370] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [203748.706627] CR2: 00007f4019252440 CR3: 00000000a621e000 CR4: 0000000000060670
      [203748.707124] Stack:
      [203748.707371]  ffff88006ff4b828 ffffffffa0609f52 ffff88006ff4b838 0000000000000001
      [203748.707885]  0000000000000000 0000000000000000 ffff880bf67c3800 ffffffffa05eca00
      [203748.708399]  00000000023079ff ffffffff81c58b80 0000000000000000 0000000000000000
      [203748.708915] Call Trace:
      [203748.709175]  [<ffffffffa0609f52>] ? ocfs2_inode_cache_io_unlock+0x12/0x20 [ocfs2]
      [203748.709680]  [<ffffffffa05eca00>] ? ocfs2_empty_dir_filldir+0x80/0x80 [ocfs2]
      [203748.710185]  [<ffffffffa05ec0cb>] ocfs2_read_dir_block_direct+0x3b/0x200 [ocfs2]
      [203748.710691]  [<ffffffffa05f0fbf>] ocfs2_prepare_dx_dir_for_insert.isra.57+0x19f/0xf60 [ocfs2]
      [203748.711204]  [<ffffffffa065660f>] ? ocfs2_metadata_cache_io_unlock+0x1f/0x30 [ocfs2]
      [203748.711716]  [<ffffffffa05f4f3a>] ocfs2_prepare_dir_for_insert+0x13a/0x890 [ocfs2]
      [203748.712227]  [<ffffffffa05f442e>] ? ocfs2_check_dir_for_entry+0x8e/0x140 [ocfs2]
      [203748.712737]  [<ffffffffa061b2f2>] ocfs2_mknod+0x4b2/0x1370 [ocfs2]
      [203748.713003]  [<ffffffffa061c385>] ocfs2_create+0x65/0x170 [ocfs2]
      [203748.713263]  [<ffffffff8121714b>] vfs_create+0xdb/0x150
      [203748.713518]  [<ffffffff8121b225>] do_last+0x815/0x1210
      [203748.713772]  [<ffffffff812192e9>] ? path_init+0xb9/0x450
      [203748.714123]  [<ffffffff8121bca0>] path_openat+0x80/0x600
      [203748.714378]  [<ffffffff811bcd45>] ? handle_pte_fault+0xd15/0x1620
      [203748.714634]  [<ffffffff8121d7ba>] do_filp_open+0x3a/0xb0
      [203748.714888]  [<ffffffff8122a767>] ? __alloc_fd+0xa7/0x130
      [203748.715143]  [<ffffffff81209ffc>] do_sys_open+0x12c/0x220
      [203748.715403]  [<ffffffff81026ddb>] ? syscall_trace_enter_phase1+0x11b/0x180
      [203748.715668]  [<ffffffff816f0c9f>] ? system_call_after_swapgs+0xe9/0x190
      [203748.715928]  [<ffffffff8120a10e>] SyS_open+0x1e/0x20
      [203748.716184]  [<ffffffff816f0d5e>] system_call_fastpath+0x18/0xd7
      [203748.716440] Code: 00 00 48 8b 7b 08 48 83 c3 10 45 89 f8 44 89 e1 44 89 f2 4c 89 ee e8 07 06 11 e1 48 8b 03 48 85 c0 75 df 8b 5d c8 e9 4d fa ff ff <0f> 0b 48 8b 7d a0 e8 dc c6 06 00 48 b8 00 00 00 00 00 00 00 10
      [203748.717505] RIP  [<ffffffffa05e9f09>] ocfs2_read_blocks+0x669/0x7f0 [ocfs2]
      [203748.717775]  RSP <ffff88006ff4b818>
      
      Joesph ever reported a similar panic.
      Link: https://oss.oracle.com/pipermail/ocfs2-devel/2013-May/008931.html
      
      Link: http://lkml.kernel.org/r/20180912063207.29484-1-junxiao.bi@oracle.com
      
      Signed-off-by: default avatarJunxiao Bi <junxiao.bi@oracle.com>
      Cc: Joseph Qi <jiangqi903@gmail.com>
      Cc: Mark Fasheh <mark@fasheh.com>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Changwei Ge <ge.changwei@h3c.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      234b69e3
    • Roman Gushchin's avatar
      mm: slowly shrink slabs with a relatively small number of objects · 172b06c3
      Roman Gushchin authored
      9092c71b ("mm: use sc->priority for slab shrink targets") changed the
      way that the target slab pressure is calculated and made it
      priority-based:
      
          delta = freeable >> priority;
          delta *= 4;
          do_div(delta, shrinker->seeks);
      
      The problem is that on a default priority (which is 12) no pressure is
      applied at all, if the number of potentially reclaimable objects is less
      than 4096 (1<<12).
      
      This causes the last objects on slab caches of no longer used cgroups to
      (almost) never get reclaimed.  It's obviously a waste of memory.
      
      It can be especially painful, if these stale objects are holding a
      reference to a dying cgroup.  Slab LRU lists are reparented on memcg
      offlining, but corresponding objects are still holding a reference to the
      dying cgroup.  If we don't scan these objects, the dying cgroup can't go
      away.  Most likely, the parent cgroup hasn't any directly charged objects,
      only remaining objects from dying children cgroups.  So it can easily hold
      a reference to hundreds of dying cgroups.
      
      If there are no big spikes in memory pressure, and new memory cgroups are
      created and destroyed periodically, this causes the number of dying
      cgroups grow steadily, causing a slow-ish and hard-to-detect memory
      "leak".  It's not a real leak, as the memory can be eventually reclaimed,
      but it could not happen in a real life at all.  I've seen hosts with a
      steadily climbing number of dying cgroups, which doesn't show any signs of
      a decline in months, despite the host is loaded with a production
      workload.
      
      It is an obvious waste of memory, and to prevent it, let's apply a minimal
      pressure even on small shrinker lists.  E.g.  if there are freeable
      objects, let's scan at least min(freeable, scan_batch) objects.
      
      This fix significantly improves a chance of a dying cgroup to be
      reclaimed, and together with some previous patches stops the steady growth
      of the dying cgroups number on some of our hosts.
      
      Link: http://lkml.kernel.org/r/20180905230759.12236-1-guro@fb.com
      Fixes: 9092c71b
      
       ("mm: use sc->priority for slab shrink targets")
      Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
      Acked-by: default avatarRik van Riel <riel@surriel.com>
      Cc: Josef Bacik <jbacik@fb.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Shakeel Butt <shakeelb@google.com>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      172b06c3
    • YueHaibing's avatar
    • Joel Fernandes (Google)'s avatar
      mm: shmem.c: Correctly annotate new inodes for lockdep · b45d71fb
      Joel Fernandes (Google) authored
      Directories and inodes don't necessarily need to be in the same lockdep
      class.  For ex, hugetlbfs splits them out too to prevent false positives
      in lockdep.  Annotate correctly after new inode creation.  If its a
      directory inode, it will be put into a different class.
      
      This should fix a lockdep splat reported by syzbot:
      
      > ======================================================
      > WARNING: possible circular locking dependency detected
      > 4.18.0-rc8-next-20180810+ #36 Not tainted
      > ------------------------------------------------------
      > syz-executor900/4483 is trying to acquire lock:
      > 00000000d2bfc8fe (&sb->s_type->i_mutex_key#9){++++}, at: inode_lock
      > include/linux/fs.h:765 [inline]
      > 00000000d2bfc8fe (&sb->s_type->i_mutex_key#9){++++}, at:
      > shmem_fallocate+0x18b/0x12e0 mm/shmem.c:2602
      >
      > but task is already holding lock:
      > 0000000025208078 (ashmem_mutex){+.+.}, at: ashmem_shrink_scan+0xb4/0x630
      > drivers/staging/android/ashmem.c:448
      >
      > which lock already depends on the new lock.
      >
      > -> #2 (ashmem_mutex){+.+.}:
      >        __mutex_lock_common kernel/locking/mutex.c:925 [inline]
      >        __mutex_lock+0x171/0x1700 kernel/locking/mutex.c:1073
      >        mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
      >        ashmem_mmap+0x55/0x520 drivers/staging/android/ashmem.c:361
      >        call_mmap include/linux/fs.h:1844 [inline]
      >        mmap_region+0xf27/0x1c50 mm/mmap.c:1762
      >        do_mmap+0xa10/0x1220 mm/mmap.c:1535
      >        do_mmap_pgoff include/linux/mm.h:2298 [inline]
      >        vm_mmap_pgoff+0x213/0x2c0 mm/util.c:357
      >        ksys_mmap_pgoff+0x4da/0x660 mm/mmap.c:1585
      >        __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
      >        __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
      >        __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91
      >        do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
      >        entry_SYSCALL_64_after_hwframe+0x49/0xbe
      >
      > -> #1 (&mm->mmap_sem){++++}:
      >        __might_fault+0x155/0x1e0 mm/memory.c:4568
      >        _copy_to_user+0x30/0x110 lib/usercopy.c:25
      >        copy_to_user include/linux/uaccess.h:155 [inline]
      >        filldir+0x1ea/0x3a0 fs/readdir.c:196
      >        dir_emit_dot include/linux/fs.h:3464 [inline]
      >        dir_emit_dots include/linux/fs.h:3475 [inline]
      >        dcache_readdir+0x13a/0x620 fs/libfs.c:193
      >        iterate_dir+0x48b/0x5d0 fs/readdir.c:51
      >        __do_sys_getdents fs/readdir.c:231 [inline]
      >        __se_sys_getdents fs/readdir.c:212 [inline]
      >        __x64_sys_getdents+0x29f/0x510 fs/readdir.c:212
      >        do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
      >        entry_SYSCALL_64_after_hwframe+0x49/0xbe
      >
      > -> #0 (&sb->s_type->i_mutex_key#9){++++}:
      >        lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
      >        down_write+0x8f/0x130 kernel/locking/rwsem.c:70
      >        inode_lock include/linux/fs.h:765 [inline]
      >        shmem_fallocate+0x18b/0x12e0 mm/shmem.c:2602
      >        ashmem_shrink_scan+0x236/0x630 drivers/staging/android/ashmem.c:455
      >        ashmem_ioctl+0x3ae/0x13a0 drivers/staging/android/ashmem.c:797
      >        vfs_ioctl fs/ioctl.c:46 [inline]
      >        file_ioctl fs/ioctl.c:501 [inline]
      >        do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
      >        ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
      >        __do_sys_ioctl fs/ioctl.c:709 [inline]
      >        __se_sys_ioctl fs/ioctl.c:707 [inline]
      >        __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
      >        do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
      >        entry_SYSCALL_64_after_hwframe+0x49/0xbe
      >
      > other info that might help us debug this:
      >
      > Chain exists of:
      >   &sb->s_type->i_mutex_key#9 --> &mm->mmap_sem --> ashmem_mutex
      >
      >  Possible unsafe locking scenario:
      >
      >        CPU0                    CPU1
      >        ----                    ----
      >   lock(ashmem_mutex);
      >                                lock(&mm->mmap_sem);
      >                                lock(ashmem_mutex);
      >   lock(&sb->s_type->i_mutex_key#9);
      >
      >  *** DEADLOCK ***
      >
      > 1 lock held by syz-executor900/4483:
      >  #0: 0000000025208078 (ashmem_mutex){+.+.}, at:
      > ashmem_shrink_scan+0xb4/0x630 drivers/staging/android/ashmem.c:448
      
      Link: http://lkml.kernel.org/r/20180821231835.166639-1-joel@joelfernandes.org
      
      Signed-off-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Reviewed-by: default avatarNeilBrown <neilb@suse.com>
      Suggested-by: default avatarNeilBrown <neilb@suse.com>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b45d71fb