1. 10 Feb, 2017 1 commit
    • Kees Cook's avatar
      time: Remove CONFIG_TIMER_STATS · dfb4357d
      Kees Cook authored
      
      
      Currently CONFIG_TIMER_STATS exposes process information across namespaces:
      
      kernel/time/timer_list.c print_timer():
      
              SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
      
      /proc/timer_list:
      
       #11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570
      
      Given that the tracer can give the same information, this patch entirely
      removes CONFIG_TIMER_STATS.
      Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Acked-by: default avatarJohn Stultz <john.stultz@linaro.org>
      Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
      Cc: linux-doc@vger.kernel.org
      Cc: Lai Jiangshan <jiangshanlai@gmail.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Xing Gao <xgao01@email.wm.edu>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Jessica Frazelle <me@jessfraz.com>
      Cc: kernel-hardening@lists.openwall.com
      Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Richard Cochran <richardcochran@gmail.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Michal Marek <mmarek@suse.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Olof Johansson <olof@lixom.net>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: linux-api@vger.kernel.org
      Cc: Arjan van de Ven <arjan@linux.intel.com>
      Link: http://lkml.kernel.org/r/20170208192659.GA32582@beast
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      dfb4357d
  2. 07 Feb, 2017 10 commits
  3. 04 Feb, 2017 1 commit
    • Waiman Long's avatar
      tick/broadcast: Reduce lock cacheline contention · 668802c2
      Waiman Long authored
      
      
      It was observed that on an Intel x86 system without the ARAT (Always
      running APIC timer) feature and with fairly large number of CPUs as
      well as CPUs coming in and out of intel_idle frequently, the lock
      contention on the tick_broadcast_lock can become significant.
      
      To reduce contention, the lock is put into its own cacheline and all
      the cpumask_var_t variables are put into the __read_mostly section.
      
      Running the SP benchmark of the NAS Parallel Benchmarks on a 4-socket
      16-core 32-thread Nehalam system, the performance number improved
      from 3353.94 Mop/s to 3469.31 Mop/s when this patch was applied on
      a 4.9.6 kernel.  This is a 3.4% improvement.
      Signed-off-by: default avatarWaiman Long <longman@redhat.com>
      Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Link: http://lkml.kernel.org/r/1485799063-20857-1-git-send-email-longman@redhat.com
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      668802c2
  4. 30 Jan, 2017 1 commit
  5. 27 Jan, 2017 1 commit
  6. 22 Jan, 2017 1 commit
    • Jiri Slaby's avatar
      x86/timer: Make delay() work during early bootup · 4c45c516
      Jiri Slaby authored
      
      
      When a panic happens during bootup, "Rebooting in X seconds.." is
      shown, but reboot happens immediatelly. It is because panic() uses mdelay()
      and mdelay() calls __const_udelay() immediately, which does not
      work while booting.
      
      The per_cpu cpu_info.loops_per_jiffy value is not initialized yet, so
      __const_udelay() actually multiplies the number of loops by zero. This
      results in __const_udelay() to delay the execution only by a nanosecond
      or so.
      
      So check whether cpu_info.loops_per_jiffy is zero and use
      loops_per_jiffy in that case. mdelay() will not be so precise without
      proper calibration, but it works relatively well.
      
      Before:
      
        [    0.170039] delaying 100ms
        [    0.170828] done
      
      After
      
        [    0.214042] delaying 100ms
        [    0.313974] done
      
      I do not think the added check matters given we are about to spin the
      processor in the next few hundred cycles.
      Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
      Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Link: http://lkml.kernel.org/r/20170119114730.2670-1-jslaby@suse.cz
      
      
      [ Minor edits. ]
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      4c45c516
  7. 20 Jan, 2017 2 commits
  8. 14 Jan, 2017 6 commits
    • Peter Zijlstra's avatar
      math64, timers: Fix 32bit mul_u64_u32_shr() and friends · 9e3d6223
      Peter Zijlstra authored
      
      
      It turns out that while GCC-4.4 manages to generate 32x32->64 mult
      instructions for the 32bit mul_u64_u32_shr() code, any GCC after that
      fails horribly.
      
      Fix this by providing an explicit mul_u32_u32() function which can be
      architcture provided.
      Reported-by: default avatarChris Metcalf <cmetcalf@mellanox.com>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
      Cc: Christopher S. Hall <christopher.s.hall@intel.com>
      Cc: David Gibson <david@gibson.dropbear.id.au>
      Cc: John Stultz <john.stultz@linaro.org>
      Cc: Laurent Vivier <lvivier@redhat.com>
      Cc: Liav Rehana <liavr@mellanox.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Parit Bhargava <prarit@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Richard Cochran <richardcochran@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20161209083011.GD15765@worktop.programming.kicks-ass.net
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      9e3d6223
    • Linus Torvalds's avatar
      Merge branch 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs · e96f8f18
      Linus Torvalds authored
      Pull btrfs fixes from Chris Mason:
       "These are all over the place.
      
        The tracepoint part of the pull fixes a crash and adds a little more
        information to two tracepoints, while the rest are good old fashioned
        fixes"
      
      * 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
        btrfs: make tracepoint format strings more compact
        Btrfs: add truncated_len for ordered extent tracepoints
        Btrfs: add 'inode' for extent map tracepoint
        btrfs: fix crash when tracepoint arguments are freed by wq callbacks
        Btrfs: adjust outstanding_extents counter properly when dio write is split
        Btrfs: fix lockdep warning about log_mutex
        Btrfs: use down_read_nested to make lockdep silent
        btrfs: fix locking when we put back a delayed ref that's too new
        btrfs: fix error handling when run_delayed_extent_op fails
        btrfs: return the actual error value from  from btrfs_uuid_tree_iterate
      e96f8f18
    • Linus Torvalds's avatar
      Merge tag 'ceph-for-4.10-rc4' of git://github.com/ceph/ceph-client · 04e39627
      Linus Torvalds authored
      Pull ceph fixes from Ilya Dryomov:
       "Two small fixups for the filesystem changes that went into this merge
        window"
      
      * tag 'ceph-for-4.10-rc4' of git://github.com/ceph/ceph-client:
        ceph: fix get_oldest_context()
        ceph: fix mds cluster availability check
      04e39627
    • Linus Torvalds's avatar
      Merge tag 'vfio-v4.10-rc4' of git://github.com/awilliam/linux-vfio · af54efa4
      Linus Torvalds authored
      Pull VFIO fixes from Alex Williamson:
      
       - Cleanups and bug fixes for the mtty sample driver (Dan Carpenter)
      
       - Export and make use of has_capability() to fix incorrect use of
         ns_capable() for testing task capabilities (Jike Song)
      
      * tag 'vfio-v4.10-rc4' of git://github.com/awilliam/linux-vfio:
        vfio/type1: Remove pid_namespace.h include
        vfio iommu type1: fix the testing of capability for remote task
        capability: export has_capability
        vfio-mdev: remove some dead code
        vfio-mdev: buffer overflow in ioctl()
        vfio-mdev: return -EFAULT if copy_to_user() fails
      af54efa4
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 406732c9
      Linus Torvalds authored
      Pull KVM fixes from Paolo Bonzini:
      
       - fix for module unload vs deferred jump labels (note: there might be
         other buggy modules!)
      
       - two NULL pointer dereferences from syzkaller
      
       - also syzkaller: fix emulation of fxsave/fxrstor/sgdt/sidt, problem
         made worse during this merge window, "just" kernel memory leak on
         releases
      
       - fix emulation of "mov ss" - somewhat serious on AMD, less so on Intel
      
      * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
        KVM: x86: fix emulation of "MOV SS, null selector"
        KVM: x86: fix NULL deref in vcpu_scan_ioapic
        KVM: eventfd: fix NULL deref irqbypass consumer
        KVM: x86: Introduce segmented_write_std
        KVM: x86: flush pending lapic jump label updates on module unload
        jump_labels: API for flushing deferred jump label updates
      406732c9
    • Linus Torvalds's avatar
      Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux · a65c9259
      Linus Torvalds authored
      Pull arm64 fixes from Catalin Marinas:
      
       - Fix huge_ptep_set_access_flags() to return "changed" when any of the
         ptes in the contiguous range is changed, not just the last one
      
       - Fix the adr_l assembly macro to work in modules under KASLR
      
      * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
        arm64: assembler: make adr_l work in modules under KASLR
        arm64: hugetlb: fix the wrong return value for huge_ptep_set_access_flags
      a65c9259
  9. 13 Jan, 2017 3 commits
  10. 12 Jan, 2017 14 commits
    • Jike Song's avatar
      vfio iommu type1: fix the testing of capability for remote task · d1b333d1
      Jike Song authored
      
      
      Before the mdev enhancement type1 iommu used capable() to test the
      capability of current task; in the course of mdev development a
      new requirement, testing for another task other than current, was
      raised.  ns_capable() was used for this purpose, however it still
      tests current, the only difference is, in a specified namespace.
      
      Fix it by using has_capability() instead, which tests the cap for
      specified task in init_user_ns, the same namespace as capable().
      
      Cc: Gerd Hoffmann <kraxel@redhat.com>
      Signed-off-by: default avatarJike Song <jike.song@intel.com>
      Reviewed-by: default avatarJames Morris <james.l.morris@oracle.com>
      Reviewed-by: default avatarKirti Wankhede <kwankhede@nvidia.com>
      Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
      d1b333d1
    • Linus Torvalds's avatar
      Merge tag 'sound-4.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound · 557ed56c
      Linus Torvalds authored
      Pull sound fixes from Takashi Iwai:
       "This time we got a few more fixes than the previous rc's, and most of
        commits were about ASoC.
      
        The only significant change in the core side is the regression fix wrt
        the aux device list handling, and all the rest are driver-specific
        small / trivial fixes"
      
      * tag 'sound-4.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
        ALSA: usb-audio: Add a quirk for Plantronics BT600
        ASoC: rt5645: set sel_i2s_pre_div1 to 2
        ASoC: dpcm: Avoid putting stream state to STOP when FE stream is paused
        ASoC: Intel: Skylake: Release FW ctx in cleanup
        ASoC: Intel: bytcr-rt5640: fix settings in internal clock mode
        ASoC: fsl_ssi: set fifo watermark to more reliable value
        ASoC: nau8825: fix invalid configuration in Pre-Scalar of FLL
        ASoC: nau8825: correct the function name of register
        ASoC: Intel: Skylake: Fix to fail safely if module not available in path
        ASoC: tlv320aic3x: Mark the RESET register as volatile
        ASoC: Fix binding and probing of auxiliary components
        ASoC: wm_adsp: Don't overrun firmware file buffer when reading region data
        ASoC: Intel: bytcr_rt5640: fallback mechanism if MCLK is not enabled
        ASoC: hdmi-codec: use unsigned type to structure members with bit-field
        ASoC: topology: kfree kcontrol->private_value before freeing kcontrol
        ASoC: rsnd: don't double free kctrl
        ASoC: dwc: Fix PIO mode initialization
      557ed56c
    • Linus Torvalds's avatar
      Merge tag 'xfs-for-linus-4.10-rc4-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux · e28ac1fc
      Linus Torvalds authored
      Pull xfs fixes from Darrick Wong:
       "As promised last week, here's some stability fixes from Christoph and
        Jan Kara:
      
         - fix free space request handling when low on disk space
      
         - remove redundant log failure error messages
      
         - free truncated dirty pages instead of letting them build up
           forever"
      
      * tag 'xfs-for-linus-4.10-rc4-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
        xfs: Timely free truncated dirty pages
        xfs: don't print warnings when xfs_log_force fails
        xfs: don't rely on ->total in xfs_alloc_space_available
        xfs: adjust allocation length in xfs_alloc_space_available
        xfs: fix bogus minleft manipulations
        xfs: bump up reserved blocks in xfs_alloc_set_aside
      e28ac1fc
    • Linus Torvalds's avatar
      Merge tag 'rproc-v4.10-fixes' of git://github.com/andersson/remoteproc · 9ca277eb
      Linus Torvalds authored
      Pull remoteproc fixes from Bjorn Andersson:
       "This fixes two regressions that have been reported to be introduced in
        v4.10-rc1.
      
         - correct an incorrect usage of the kref api
      
         - revert the change to make the resource table read-only. As the
           space each vdev resource is used as virtio device config space it
           must be shared with the remote"
      
      * tag 'rproc-v4.10-fixes' of git://github.com/andersson/remoteproc:
        Revert "remoteproc: Merge table_ptr and cached_table pointers"
        remoteproc: fix vdev reference management
      9ca277eb
    • Linus Torvalds's avatar
      Merge tag 'rpmsg-v4.10-fixes' of git://github.com/andersson/remoteproc · 1d865da7
      Linus Torvalds authored
      Pull rpmsg fixes from Bjorn Andersson:
       "This fixes a regression introduced in v4.10-rc1 that prohibits
        multiple channels with the same name but different endpoint addresses
        to be used"
      
      * tag 'rpmsg-v4.10-fixes' of git://github.com/andersson/remoteproc:
        rpmsg: virtio_rpmsg_bus: fix channel creation
      1d865da7
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid · 95ce1313
      Linus Torvalds authored
      Pull HID fixes from Jiri Kosina:
      
       - device descriptor length validation fix to hid-cypress driver from
         Greg
      
       - introduction of a short delay into i2c-hid, which is not really
         mandated by the spec, but fixes Asus Touchpads
      
       - Petzl USB connectable flashlight quirk from myself
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
        HID: i2c-hid: Add sleep between POWER ON and RESET
        HID: hid-cypress: validate length of report
        HID: ignore Petzl USB headlamp
      95ce1313
    • Linus Torvalds's avatar
      Merge branch 'scsi-target-for-v4.10' of... · cb38b453
      Linus Torvalds authored
      Merge branch 'scsi-target-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/bvanassche/linux
      
      Pull scsi target fixes from Bart Van Assche:
      
       - a series of bug fixes for the XCOPY implementation from David
         Disseldorp
      
       - one bug fix for the ibmvscsis driver, a driver that is used for
         communication between partitions on IBM POWER systems.
      
      * 'scsi-target-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/bvanassche/linux:
        ibmvscsis: Fix srp_transfer_data fail return code
        target: support XCOPY requests without parameters
        target: check for XCOPY parameter truncation
        target: use XCOPY segment descriptor CSCD IDs
        target: check XCOPY segment descriptor CSCD IDs
        target: simplify XCOPY wwn->se_dev lookup helper
        target: return UNSUPPORTED TARGET/SEGMENT DESC TYPE CODE sense
        target: bounds check XCOPY total descriptor list length
        target: bounds check XCOPY segment descriptor list
        target: use XCOPY TOO MANY TARGET DESCRIPTORS sense
        target: add XCOPY target/segment desc sense codes
      cb38b453
    • Geng, Jichao's avatar
      ceph: fix get_oldest_context() · 84fcc2d2
      Geng, Jichao authored
      For no snapshot case, we should use ci->truncate_{seq,size}.
      
      Fixes: 5f743e45
      
       ("ceph: record truncate size/seq for snap data writeback")
      Signed-off-by: default avatarGeng, Jichao <geng.jichao@h3c.com>
      Signed-off-by: default avatarYan, Zheng <zyan@redhat.com>
      84fcc2d2
    • Yan, Zheng's avatar
      ceph: fix mds cluster availability check · cc8e8342
      Yan, Zheng authored
      We should apply the check after getting the initial mdsmap.
      
      Fixes: e9e427f0 ("ceph: check availability of mds cluster on mount")
      Link: http://tracker.ceph.com/issues/18161
      
      Signed-off-by: default avatarYan, Zheng <zyan@redhat.com>
      cc8e8342
    • Linus Torvalds's avatar
      Merge tag 'md/4.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md · 607ae5f2
      Linus Torvalds authored
      Pull md fixes from Shaohua Li:
       "Basically one fix for raid5 cache which is merged in this cycle,
        others are trival fixes"
      
      * tag 'md/4.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
        md/raid5: Use correct IS_ERR() variation on pointer check
        md: cleanup mddev flag clear for takeover
        md/r5cache: fix spelling mistake on "recoverying"
        md/r5cache: assign conf->log before r5l_load_log()
        md/r5cache: simplify handling of sh->log_start in recovery
        md/raid5-cache: removes unnecessary write-through mode judgments
        md/raid10: Refactor raid10_make_request
        md/raid1: Refactor raid1_make_request
      607ae5f2
    • Ard Biesheuvel's avatar
      arm64: assembler: make adr_l work in modules under KASLR · 41c066f2
      Ard Biesheuvel authored
      
      
      When CONFIG_RANDOMIZE_MODULE_REGION_FULL=y, the offset between loaded
      modules and the core kernel may exceed 4 GB, putting symbols exported
      by the core kernel out of the reach of the ordinary adrp/add instruction
      pairs used to generate relative symbol references. So make the adr_l
      macro emit a movz/movk sequence instead when executing in module context.
      
      While at it, remove the pointless special case for the stack pointer.
      Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
      Acked-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      41c066f2
    • Paolo Bonzini's avatar
      KVM: x86: fix emulation of "MOV SS, null selector" · 33ab9110
      Paolo Bonzini authored
      
      
      This is CVE-2017-2583.  On Intel this causes a failed vmentry because
      SS's type is neither 3 nor 7 (even though the manual says this check is
      only done for usable SS, and the dmesg splat says that SS is unusable!).
      On AMD it's worse: svm.c is confused and sets CPL to 0 in the vmcb.
      
      The fix fabricates a data segment descriptor when SS is set to a null
      selector, so that CPL and SS.DPL are set correctly in the VMCS/vmcb.
      Furthermore, only allow setting SS to a NULL selector if SS.RPL < 3;
      this in turn ensures CPL < 3 because RPL must be equal to CPL.
      
      Thanks to Andy Lutomirski and Willy Tarreau for help in analyzing
      the bug and deciphering the manuals.
      Reported-by: default avatarXiaohan Zhang <zhangxiaohan1@huawei.com>
      Fixes: 79d5b4c3
      
      
      Cc: stable@nongnu.org
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      33ab9110
    • Jike Song's avatar
      capability: export has_capability · 19c816e8
      Jike Song authored
      
      
      has_capability() is sometimes needed by modules to test capability
      for specified task other than current, so export it.
      
      Cc: Kirti Wankhede <kwankhede@nvidia.com>
      Signed-off-by: default avatarJike Song <jike.song@intel.com>
      Acked-by: default avatarSerge Hallyn <serge@hallyn.com>
      Acked-by: default avatarJames Morris <james.l.morris@oracle.com>
      Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
      19c816e8
    • Wanpeng Li's avatar
      KVM: x86: fix NULL deref in vcpu_scan_ioapic · 546d87e5
      Wanpeng Li authored
      
      
      Reported by syzkaller:
      
          BUG: unable to handle kernel NULL pointer dereference at 00000000000001b0
          IP: _raw_spin_lock+0xc/0x30
          PGD 3e28eb067
          PUD 3f0ac6067
          PMD 0
          Oops: 0002 [#1] SMP
          CPU: 0 PID: 2431 Comm: test Tainted: G           OE   4.10.0-rc1+ #3
          Call Trace:
           ? kvm_ioapic_scan_entry+0x3e/0x110 [kvm]
           kvm_arch_vcpu_ioctl_run+0x10a8/0x15f0 [kvm]
           ? pick_next_task_fair+0xe1/0x4e0
           ? kvm_arch_vcpu_load+0xea/0x260 [kvm]
           kvm_vcpu_ioctl+0x33a/0x600 [kvm]
           ? hrtimer_try_to_cancel+0x29/0x130
           ? do_nanosleep+0x97/0xf0
           do_vfs_ioctl+0xa1/0x5d0
           ? __hrtimer_init+0x90/0x90
           ? do_nanosleep+0x5b/0xf0
           SyS_ioctl+0x79/0x90
           do_syscall_64+0x6e/0x180
           entry_SYSCALL64_slow_path+0x25/0x25
          RIP: _raw_spin_lock+0xc/0x30 RSP: ffffa43688973cc0
      
      The syzkaller folks reported a NULL pointer dereference due to
      ENABLE_CAP succeeding even without an irqchip.  The Hyper-V
      synthetic interrupt controller is activated, resulting in a
      wrong request to rescan the ioapic and a NULL pointer dereference.
      
          #include <sys/ioctl.h>
          #include <sys/mman.h>
          #include <sys/types.h>
          #include <linux/kvm.h>
          #include <pthread.h>
          #include <stddef.h>
          #include <stdint.h>
          #include <stdlib.h>
          #include <string.h>
          #include <unistd.h>
      
          #ifndef KVM_CAP_HYPERV_SYNIC
          #define KVM_CAP_HYPERV_SYNIC 123
          #endif
      
          void* thr(void* arg)
          {
      	struct kvm_enable_cap cap;
      	cap.flags = 0;
      	cap.cap = KVM_CAP_HYPERV_SYNIC;
      	ioctl((long)arg, KVM_ENABLE_CAP, &cap);
      	return 0;
          }
      
          int main()
          {
      	void *host_mem = mmap(0, 0x1000, PROT_READ|PROT_WRITE,
      			MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
      	int kvmfd = open("/dev/kvm", 0);
      	int vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0);
      	struct kvm_userspace_memory_region memreg;
      	memreg.slot = 0;
      	memreg.flags = 0;
      	memreg.guest_phys_addr = 0;
      	memreg.memory_size = 0x1000;
      	memreg.userspace_addr = (unsigned long)host_mem;
      	host_mem[0] = 0xf4;
      	ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &memreg);
      	int cpufd = ioctl(vmfd, KVM_CREATE_VCPU, 0);
      	struct kvm_sregs sregs;
      	ioctl(cpufd, KVM_GET_SREGS, &sregs);
      	sregs.cr0 = 0;
      	sregs.cr4 = 0;
      	sregs.efer = 0;
      	sregs.cs.selector = 0;
      	sregs.cs.base = 0;
      	ioctl(cpufd, KVM_SET_SREGS, &sregs);
      	struct kvm_regs regs = { .rflags = 2 };
      	ioctl(cpufd, KVM_SET_REGS, &regs);
      	ioctl(vmfd, KVM_CREATE_IRQCHIP, 0);
      	pthread_t th;
      	pthread_create(&th, 0, thr, (void*)(long)cpufd);
      	usleep(rand() % 10000);
      	ioctl(cpufd, KVM_RUN, 0);
      	pthread_join(th, 0);
      	return 0;
          }
      
      This patch fixes it by failing ENABLE_CAP if without an irqchip.
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Fixes: 5c919412
      
       (kvm/x86: Hyper-V synthetic interrupt controller)
      Cc: stable@vger.kernel.org # 4.5+
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarWanpeng Li <wanpeng.li@hotmail.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      546d87e5