1. 07 Aug, 2017 3 commits
  2. 17 Jul, 2017 1 commit
  3. 15 Jul, 2017 23 commits
    • Linus Torvalds's avatar
      Linux v4.13-rc1 · 5771a8c0
      Linus Torvalds authored
      5771a8c0
    • Linus Torvalds's avatar
      Merge tag 'standardize-docs' of git://git.lwn.net/linux · 486088bc
      Linus Torvalds authored
      Pull documentation format standardization from Jonathan Corbet:
       "This series converts a number of top-level documents to the RST format
        without incorporating them into the Sphinx tree. The hope is to bring
        some uniformity to kernel documentation and, perhaps more importantly,
        have our existing docs serve as an example of the desired formatting
        for those that will be added later.
      
        Mauro has gone through and fixed up a lot of top-level documentation
        files to make them conform to the RST format, but without moving or
        renaming them in any way. This will help when we incorporate the ones
        we want to keep into the Sphinx doctree, but the real purpose is to
        bring a bit of uniformity to our documentation and let the top-level
        docs serve as examples for those writing new ones"
      
      * tag 'standardize-docs' of git://git.lwn.net/linux: (84 commits)
        docs: kprobes.txt: Fix whitespacing
        tee.txt: standardize document format
        cgroup-v2.txt: standardize document format
        dell_rbu.txt: standardize document format
        zorro.txt: standardize document format
        xz.txt: standardize document format
        xillybus.txt: standardize document format
        vfio.txt: standardize document format
        vfio-mediated-device.txt: standardize document format
        unaligned-memory-access.txt: standardize document format
        this_cpu_ops.txt: standardize document format
        svga.txt: standardize document format
        static-keys.txt: standardize document format
        smsc_ece1099.txt: standardize document format
        SM501.txt: standardize document format
        siphash.txt: standardize document format
        sgi-ioc4.txt: standardize document format
        SAK.txt: standardize document format
        rpmsg.txt: standardize document format
        robust-futexes.txt: standardize document format
        ...
      486088bc
    • Linus Torvalds's avatar
      Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random · 52f6c588
      Linus Torvalds authored
      Pull random updates from Ted Ts'o:
       "Add wait_for_random_bytes() and get_random_*_wait() functions so that
        callers can more safely get random bytes if they can block until the
        CRNG is initialized.
      
        Also print a warning if get_random_*() is called before the CRNG is
        initialized. By default, only one single-line warning will be printed
        per boot. If CONFIG_WARN_ALL_UNSEEDED_RANDOM is defined, then a
        warning will be printed for each function which tries to get random
        bytes before the CRNG is initialized. This can get spammy for certain
        architecture types, so it is not enabled by default"
      
      * tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
        random: reorder READ_ONCE() in get_random_uXX
        random: suppress spammy warnings about unseeded randomness
        random: warn when kernel uses unseeded randomness
        net/route: use get_random_int for random counter
        net/neighbor: use get_random_u32 for 32-bit hash random
        rhashtable: use get_random_u32 for hash_rnd
        ceph: ensure RNG is seeded before using
        iscsi: ensure RNG is seeded before use
        cifs: use get_random_u32 for 32-bit lock random
        random: add get_random_{bytes,u32,u64,int,long,once}_wait family
        random: add wait_for_random_bytes() API
      52f6c588
    • Linus Torvalds's avatar
      Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 78dcf734
      Linus Torvalds authored
      Pull ->s_options removal from Al Viro:
       "Preparations for fsmount/fsopen stuff (coming next cycle). Everything
        gets moved to explicit ->show_options(), killing ->s_options off +
        some cosmetic bits around fs/namespace.c and friends. Basically, the
        stuff needed to work with fsmount series with minimum of conflicts
        with other work.
      
        It's not strictly required for this merge window, but it would reduce
        the PITA during the coming cycle, so it would be nice to have those
        bits and pieces out of the way"
      
      * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        isofs: Fix isofs_show_options()
        VFS: Kill off s_options and helpers
        orangefs: Implement show_options
        9p: Implement show_options
        isofs: Implement show_options
        afs: Implement show_options
        affs: Implement show_options
        befs: Implement show_options
        spufs: Implement show_options
        bpf: Implement show_options
        ramfs: Implement show_options
        pstore: Implement show_options
        omfs: Implement show_options
        hugetlbfs: Implement show_options
        VFS: Don't use save/replace_mount_options if not using generic_show_options
        VFS: Provide empty name qstr
        VFS: Make get_filesystem() return the affected filesystem
        VFS: Clean up whitespace in fs/namespace.c and fs/super.c
        Provide a function to create a NUL-terminated string from unterminated data
      78dcf734
    • Linus Torvalds's avatar
      Merge branch 'work.__copy_to_user' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 93ff8185
      Linus Torvalds authored
      Pull more __copy_.._user elimination from Al Viro.
      
      * 'work.__copy_to_user' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        drm_dp_aux_dev: switch to read_iter/write_iter
      93ff8185
    • Linus Torvalds's avatar
      Merge branch 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 89cbec71
      Linus Torvalds authored
      Pull uacess-unaligned removal from Al Viro:
       "That stuff had just one user, and an exotic one, at that - binfmt_flat
        on arm and m68k"
      
      * 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        kill {__,}{get,put}_user_unaligned()
        binfmt_flat: flat_{get,put}_addr_from_rp() should be able to fail
      89cbec71
    • Linus Torvalds's avatar
      Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 2173bd06
      Linus Torvalds authored
      Pull network field-by-field copy-in updates from Al Viro:
       "This part of the misc compat queue was held back for review from
        networking folks and since davem has jus ACKed those..."
      
      * 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        get_compat_bpf_fprog(): don't copyin field-by-field
        get_compat_msghdr(): get rid of field-by-field copyin
        copy_msghdr_from_user(): get rid of field-by-field copyin
      2173bd06
    • Linus Torvalds's avatar
      Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus · 568d135d
      Linus Torvalds authored
      Pull MIPS updates from Ralf Baechle:
       "Boston platform support:
         - Document DT bindings
         - Add CLK driver for board clocks
      
        CM:
         - Avoid per-core locking with CM3 & higher
         - WARN on attempt to lock invalid VP, not BUG
      
        CPS:
         - Select CONFIG_SYS_SUPPORTS_SCHED_SMT for MIPSr6
         - Prevent multi-core with dcache aliasing
         - Handle cores not powering down more gracefully
         - Handle spurious VP starts more gracefully
      
        DSP:
         - Add lwx & lhx missaligned access support
      
        eBPF:
         - Add MIPS support along with many supporting change to add the
           required infrastructure
      
        Generic arch code:
         - Misc sysmips MIPS_ATOMIC_SET fixes
         - Drop duplicate HAVE_SYSCALL_TRACEPOINTS
         - Negate error syscall return in trace
         - Correct forced syscall errors
         - Traced negative syscalls should return -ENOSYS
         - Allow samples/bpf/tracex5 to access syscall arguments for sane
           traces
         - Cleanup from old Kconfig options in defconfigs
         - Fix PREF instruction usage by memcpy for MIPS R6
         - Fix various special cases in the FPU eulation
         - Fix some special cases in MIPS16e2 support
         - Fix MIPS I ISA /proc/cpuinfo reporting
         - Sort MIPS Kconfig alphabetically
         - Fix minimum alignment requirement of IRQ stack as required by
           ABI / GCC
         - Fix special cases in the module loader
         - Perform post-DMA cache flushes on systems with MAARs
         - Probe the I6500 CPU
         - Cleanup cmpxchg and add support for 1 and 2 byte operations
         - Use queued read/write locks (qrwlock)
         - Use queued spinlocks (qspinlock)
         - Add CPU shared FTLB feature detection
         - Handle tlbex-tlbp race condition
         - Allow storing pgd in C0_CONTEXT for MIPSr6
         - Use current_cpu_type() in m4kc_tlbp_war()
         - Support Boston in the generic kernel
      
        Generic platform:
         - yamon-dt: Pull YAMON DT shim code out of SEAD-3 board
         - yamon-dt: Support > 256MB of RAM
         - yamon-dt: Use serial* rather than uart* aliases
         - Abstract FDT fixup application
         - Set RTC_ALWAYS_BCD to 0
         - Add a MAINTAINERS entry
      
        core kernel:
         - qspinlock.c: include linux/prefetch.h
      
        Loongson 3:
         - Add support
      
        Perf:
         - Add I6500 support
      
        SEAD-3:
         - Remove GIC timer from DT
         - Set interrupt-parent per-device, not at root node
         - Fix GIC interrupt specifiers
      
        SMP:
         - Skip IPI setup if we only have a single CPU
      
        VDSO:
         - Make comment match reality
         - Improvements to time code in VDSO"
      
      * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (86 commits)
        locking/qspinlock: Include linux/prefetch.h
        MIPS: Fix MIPS I ISA /proc/cpuinfo reporting
        MIPS: Fix minimum alignment requirement of IRQ stack
        MIPS: generic: Support MIPS Boston development boards
        MIPS: DTS: img: Don't attempt to build-in all .dtb files
        clk: boston: Add a driver for MIPS Boston board clocks
        dt-bindings: Document img,boston-clock binding
        MIPS: Traced negative syscalls should return -ENOSYS
        MIPS: Correct forced syscall errors
        MIPS: Negate error syscall return in trace
        MIPS: Drop duplicate HAVE_SYSCALL_TRACEPOINTS select
        MIPS16e2: Provide feature overrides for non-MIPS16 systems
        MIPS: MIPS16e2: Report ASE presence in /proc/cpuinfo
        MIPS: MIPS16e2: Subdecode extended LWSP/SWSP instructions
        MIPS: MIPS16e2: Identify ASE presence
        MIPS: VDSO: Fix a mismatch between comment and preprocessor constant
        MIPS: VDSO: Add implementation of gettimeofday() fallback
        MIPS: VDSO: Add implementation of clock_gettime() fallback
        MIPS: VDSO: Fix conversions in do_monotonic()/do_monotonic_coarse()
        MIPS: Use current_cpu_type() in m4kc_tlbp_war()
        ...
      568d135d
    • Linus Torvalds's avatar
      Merge branch 'for-linus-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml · 4ecd4ff5
      Linus Torvalds authored
      Pull UML updates from Richard Weinberger:
       "Mostly fixes for UML:
      
         - First round of fixes for PTRACE_GETRESET/SETREGSET
      
         - A printf vs printk cleanup
      
         - Minor improvements"
      
      * 'for-linus-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
        um: Correctly check for PTRACE_GETRESET/SETREGSET
        um: v2: Use generic NOTES macro
        um: Add kerneldoc for userspace_tramp() and start_userspace()
        um: Add kerneldoc for segv_handler
        um: stub-data.h: remove superfluous include
        um: userspace - be more verbose in ptrace set regs error
        um: add dummy ioremap and iounmap functions
        um: Allow building and running on older hosts
        um: Avoid longjmp/setjmp symbol clashes with libpthread.a
        um: console: Ignore console= option
        um: Use os_warn to print out pre-boot warning/error messages
        um: Add os_warn() for pre-boot warning/error messages
        um: Use os_info for the messages on normal path
        um: Add os_info() for pre-boot information messages
        um: Use printk instead of printf in make_uml_dir
      4ecd4ff5
    • Linus Torvalds's avatar
      Merge tag 'upstream-4.13-rc1' of git://git.infradead.org/linux-ubifs · 966859b9
      Linus Torvalds authored
      Pull UBIFS updates from Richard Weinberger:
      
       - Updates and fixes for the file encryption mode
      
       - Minor improvements
      
       - Random fixes
      
      * tag 'upstream-4.13-rc1' of git://git.infradead.org/linux-ubifs:
        ubifs: Set double hash cookie also for RENAME_EXCHANGE
        ubifs: Massage assert in ubifs_xattr_set() wrt. init_xattrs
        ubifs: Don't leak kernel memory to the MTD
        ubifs: Change gfp flags in page allocation for bulk read
        ubifs: Fix oops when remounting with no_bulk_read.
        ubifs: Fail commit if TNC is obviously inconsistent
        ubifs: allow userspace to map mounts to volumes
        ubifs: Wire-up statx() support
        ubifs: Remove dead code from ubifs_get_link()
        ubifs: Massage debug prints wrt. fscrypt
        ubifs: Add assert to dent_key_init()
        ubifs: Fix unlink code wrt. double hash lookups
        ubifs: Fix data node size for truncating uncompressed nodes
        ubifs: Don't encrypt special files on creation
        ubifs: Fix memory leak in RENAME_WHITEOUT error path in do_rename
        ubifs: Fix inode data budget in ubifs_mknod
        ubifs: Correctly evict xattr inodes
        ubifs: Unexport ubifs_inode_slab
        ubifs: don't bother checking for encryption key in ->mmap()
        ubifs: require key for truncate(2) of encrypted file
      966859b9
    • Linus Torvalds's avatar
      Merge tag 'kvm-4.13-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm · e37a07e0
      Linus Torvalds authored
      Pull more KVM updates from Radim Krčmář:
       "Second batch of KVM updates for v4.13
      
        Common:
         - add uevents for VM creation/destruction
         - annotate and properly access RCU-protected objects
      
        s390:
         - rename IOCTL added in the first v4.13 merge
      
        x86:
         - emulate VMLOAD VMSAVE feature in SVM
         - support paravirtual asynchronous page fault while nested
         - add Hyper-V userspace interfaces for better migration
         - improve master clock corner cases
         - extend internal error reporting after EPT misconfig
         - correct single-stepping of emulated instructions in SVM
         - handle MCE during VM entry
         - fix nVMX VM entry checks and nVMX VMCS shadowing"
      
      * tag 'kvm-4.13-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
        kvm: x86: hyperv: make VP_INDEX managed by userspace
        KVM: async_pf: Let guest support delivery of async_pf from guest mode
        KVM: async_pf: Force a nested vmexit if the injected #PF is async_pf
        KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
        KVM: x86: Simplify kvm_x86_ops->queue_exception parameter list
        kvm: x86: hyperv: add KVM_CAP_HYPERV_SYNIC2
        KVM: x86: make backwards_tsc_observed a per-VM variable
        KVM: trigger uevents when creating or destroying a VM
        KVM: SVM: Enable Virtual VMLOAD VMSAVE feature
        KVM: SVM: Add Virtual VMLOAD VMSAVE feature definition
        KVM: SVM: Rename lbr_ctl field in the vmcb control area
        KVM: SVM: Prepare for new bit definition in lbr_ctl
        KVM: SVM: handle singlestep exception when skipping emulated instructions
        KVM: x86: take slots_lock in kvm_free_pit
        KVM: s390: Fix KVM_S390_GET_CMMA_BITS ioctl definition
        kvm: vmx: Properly handle machine check during VM-entry
        KVM: x86: update master clock before computing kvmclock_offset
        kvm: nVMX: Shadow "high" parts of shadowed 64-bit VMCS fields
        kvm: nVMX: Fix nested_vmx_check_msr_bitmap_controls
        kvm: nVMX: Validate the I/O bitmaps on nested VM-entry
        ...
      e37a07e0
    • Sebastian Andrzej Siewior's avatar
      random: reorder READ_ONCE() in get_random_uXX · 72e5c740
      Sebastian Andrzej Siewior authored
      Avoid the READ_ONCE in commit 4a072c71 ("random: silence compiler
      warnings and fix race") if we can leave the function after
      arch_get_random_XXX().
      
      Cc: Jason A. Donenfeld <Jason@zx2c4.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
      72e5c740
    • Theodore Ts'o's avatar
      random: suppress spammy warnings about unseeded randomness · eecabf56
      Theodore Ts'o authored
      Unfortunately, on some models of some architectures getting a fully
      seeded CRNG is extremely difficult, and so this can result in dmesg
      getting spammed for a surprisingly long time.  This is really bad from
      a security perspective, and so architecture maintainers really need to
      do what they can to get the CRNG seeded sooner after the system is
      booted.  However, users can't do anything actionble to address this,
      and spamming the kernel messages log will only just annoy people.
      
      For developers who want to work on improving this situation,
      CONFIG_WARN_UNSEEDED_RANDOM has been renamed to
      CONFIG_WARN_ALL_UNSEEDED_RANDOM.  By default the kernel will always
      print the first use of unseeded randomness.  This way, hopefully the
      security obsessed will be happy that there is _some_ indication when
      the kernel boots there may be a potential issue with that architecture
      or subarchitecture.  To see all uses of unseeded randomness,
      developers can enable CONFIG_WARN_ALL_UNSEEDED_RANDOM.
      Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
      eecabf56
    • Linus Torvalds's avatar
      Merge tag 'xfs-4.13-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux · a80099a1
      Linus Torvalds authored
      Pull XFS fixes from Darrick Wong:
       "Largely debugging and regression fixes.
      
         - Add some locking assertions for the _ilock helpers.
      
         - Revert the XFS_QMOPT_NOLOCK patch; after discussion with hch the
           online fsck patch that would have needed it has been redesigned and
           no longer needs it.
      
         - Fix behavioral regression of SEEK_HOLE/DATA with negative offsets
           to match 4.12-era XFS behavior"
      
      * tag 'xfs-4.13-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
        vfs: in iomap seek_{hole,data}, return -ENXIO for negative offsets
        Revert "xfs: grab dquots without taking the ilock"
        xfs: assert locking precondition in xfs_readlink_bmap_ilocked
        xfs: assert locking precondіtion in xfs_attr_list_int_ilocked
        xfs: fixup xfs_attr_get_ilocked
      a80099a1
    • Linus Torvalds's avatar
      Merge branch 'for-4.13-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux · bc243704
      Linus Torvalds authored
      Pull btrfs fixes from David Sterba:
       "We've identified and fixed a silent corruption (introduced by code in
        the first pull), a fixup after the blk_status_t merge and two fixes to
        incremental send that Filipe has been hunting for some time"
      
      * 'for-4.13-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
        Btrfs: fix unexpected return value of bio_readpage_error
        btrfs: btrfs_create_repair_bio never fails, skip error handling
        btrfs: cloned bios must not be iterated by bio_for_each_segment_all
        Btrfs: fix write corruption due to bio cloning on raid5/6
        Btrfs: incremental send, fix invalid memory access
        Btrfs: incremental send, fix invalid path for link commands
      bc243704
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input · 0ffff118
      Linus Torvalds authored
      Pull a few more input updates from Dmitry Torokhov:
      
       - multi-touch handling for Xen
      
       - fix for long-standing bug causing crashes in i8042 on boot
      
       - change to gpio_keys to better handle key presses during system state
         transition
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
        Input: i8042 - fix crash at boot time
        Input: gpio_keys - handle the missing key press event in resume phase
        Input: xen-kbdfront - add multi-touch support
      0ffff118
    • Linus Torvalds's avatar
      Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 · dcf903d0
      Linus Torvalds authored
      Pull crypto fixes from Herbert Xu:
      
       - fix new compiler warnings in cavium
      
       - set post-op IV properly in caam (this fixes chaining)
      
       - fix potential use-after-free in atmel in case of EBUSY
      
       - fix sleeping in softirq path in chcr
      
       - disable buggy sha1-avx2 driver (may overread and page fault)
      
       - fix use-after-free on signals in caam
      
      * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
        crypto: cavium - make several functions static
        crypto: chcr - Avoid algo allocation in softirq.
        crypto: caam - properly set IV after {en,de}crypt
        crypto: atmel - only treat EBUSY as transient if backlog
        crypto: af_alg - Avoid sock_graft call warning
        crypto: caam - fix signals handling
        crypto: sha1-ssse3 - Disable avx2
      dcf903d0
    • Linus Torvalds's avatar
      Merge tag 'devprop-fix-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 96d0d831
      Linus Torvalds authored
      Pull device properties framework fix from Rafael Wysocki:
       "This fixes a problem with bool properties that could be seen as "true"
        when the property was not present at all by adding a special helper
        for bool properties with checks for all of the requisute conditions
        (Sakari Ailus)"
      
      * tag 'devprop-fix-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
        device property: Introduce fwnode_call_bool_op() for ops that return bool
      96d0d831
    • Linus Torvalds's avatar
      Merge tag 'acpi-fixes-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 1ef27400
      Linus Torvalds authored
      Pull ACPI fixes from Rafael Wysocki:
       "These fix the return value of an IRQ mapping routine in the ACPI core,
        fix an EC driver issue causing abnormal fan behavior after system
        resume on some systems and add quirks for ACPI device objects that
        need to be treated as "always present" to work around bogus
        implementations of the _STA control method.
      
        Specifics:
      
         - Fix the return value of acpi_gsi_to_irq() to make the GSI to IRQ
           mapping work on the Mustang (ARM64) platform (Mark Salter).
      
         - Fix an EC driver issue that causes fans to behave abnormally after
           system resume on some systems which turns out to be related to
           switching over the EC into the polling mode during the noirq stages
           of system suspend and resume (Lv Zheng).
      
         - Add quirks for ACPI device objects that need to be treated as
           "always present", because their _STA methods are designed to work
           around Windows driver bugs and return garbage from our perspective
           (Hans de Goede)"
      
      * tag 'acpi-fixes-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
        ACPI / x86: Add KIOX000A accelerometer on GPD win to always_present_ids array
        ACPI / x86: Add Dell Venue 11 Pro 7130 touchscreen to always_present_ids
        ACPI / x86: Allow matching always_present_id array entries by DMI
        Revert "ACPI / EC: Enable event freeze mode..." to fix a regression
        ACPI / EC: Drop EC noirq hooks to fix a regression
        ACPI / irq: Fix return code of acpi_gsi_to_irq()
      1ef27400
    • Linus Torvalds's avatar
      Merge tag 'pm-fixes-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · e37720e2
      Linus Torvalds authored
      Pull power management fixes from Rafael Wysocki:
       "These fix a recently exposed issue in the PCI device wakeup code and
        one older problem related to PCI device wakeup that has been reported
        recently, modify one more piece of computations in intel_pstate to get
        rid of a rounding error, fix a possible race in the schedutil cpufreq
        governor, fix the device PM QoS sysfs interface to correctly handle
        invalid user input, fix return values of two probe routines in devfreq
        drivers and constify an attribute_group structure in devfreq.
      
        Specifics:
      
         - Avoid clearing the PCI PME Enable bit for devices as a result of
           config space restoration which confuses AML executed afterward and
           causes wakeup events to be lost on some systems (Rafael Wysocki).
      
         - Fix the native PCIe PME interrupts handling in the cases when the
           PME IRQ is set up as a system wakeup one so that runtime PM remote
           wakeup works as expected after system resume on systems where that
           happens (Rafael Wysocki).
      
         - Fix the device PM QoS sysfs interface to handle invalid user input
           correctly instead of using an unititialized variable value as the
           latency tolerance for the device at hand (Dan Carpenter).
      
         - Get rid of one more rounding error from intel_pstate computations
           (Srinivas Pandruvada).
      
         - Fix the schedutil cpufreq governor to prevent it from possibly
           accessing unititialized data structures from governor callbacks in
           some cases on systems when multiple CPUs share a single cpufreq
           policy object (Vikram Mulukutla).
      
         - Fix the return values of probe routines in two devfreq drivers
           (Gustavo Silva).
      
         - Constify an attribute_group structure in devfreq (Arvind Yadav)"
      
      * tag 'pm-fixes-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
        PCI / PM: Fix native PME handling during system suspend/resume
        PCI / PM: Restore PME Enable after config space restoration
        cpufreq: schedutil: Fix sugov_start() versus sugov_update_shared() race
        PM / QoS: return -EINVAL for bogus strings
        cpufreq: intel_pstate: Fix ratio setting for min_perf_pct
        PM / devfreq: constify attribute_group structures.
        PM / devfreq: tegra: fix error return code in tegra_devfreq_probe()
        PM / devfreq: rk3399_dmc: fix error return code in rk3399_dmcfreq_probe()
      e37720e2
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · 867eacd7
      Linus Torvalds authored
      Merge even more updates from Andrew Morton:
      
       - a few leftovers
      
       - fault-injector rework
      
       - add a module loader test driver
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>:
        kmod: throttle kmod thread limit
        kmod: add test driver to stress test the module loader
        MAINTAINERS: give kmod some maintainer love
        xtensa: use generic fb.h
        fault-inject: add /proc/<pid>/fail-nth
        fault-inject: simplify access check for fail-nth
        fault-inject: make fail-nth read/write interface symmetric
        fault-inject: parse as natural 1-based value for fail-nth write interface
        fault-inject: automatically detect the number base for fail-nth write interface
        kernel/watchdog.c: use better pr_fmt prefix
        MAINTAINERS: move the befs tree to kernel.org
        lib/atomic64_test.c: add a test that atomic64_inc_not_zero() returns an int
        mm: fix overflow check in expand_upwards()
      867eacd7
    • Daniel Micay's avatar
      replace incorrect strscpy use in FORTIFY_SOURCE · 077d2ba5
      Daniel Micay authored
      Using strscpy was wrong because FORTIFY_SOURCE is passing the maximum
      possible size of the outermost object, but strscpy defines the count
      parameter as the exact buffer size, so this could copy past the end of
      the source.  This would still be wrong with the planned usage of
      __builtin_object_size(p, 1) for intra-object overflow checks since it's
      the maximum possible size of the specified object with no guarantee of
      it being that large.
      
      Reuse of the fortified functions like this currently makes the runtime
      error reporting less precise but that can be improved later on.
      
      Noticed by Dave Jones and KASAN.
      Signed-off-by: default avatarDaniel Micay <danielmicay@gmail.com>
      Acked-by: default avatarKees Cook <keescook@chromium.org>
      Reported-by: default avatarDave Jones <davej@codemonkey.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      077d2ba5
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile · 01ea9177
      Linus Torvalds authored
      Pull arch/tile updates from Chris Metcalf:
       "This adds support for an <arch/intreg.h> to help with removing
        __need_xxx #defines from glibc, and removes some dead code in
        arch/tile/mm/init.c"
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
        mm, tile: drop arch_{add,remove}_memory
        tile: prefer <arch/intreg.h> to __need_int_reg_t
      01ea9177
  4. 14 Jul, 2017 13 commits
    • Linus Torvalds's avatar
      Merge tag 'powerpc-4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · deed9deb
      Linus Torvalds authored
      Pull powerpc fixes from Michael Ellerman:
       "Nothing that really stands out, just a bunch of fixes that have come
        in in the last couple of weeks.
      
        None of these are actually fixes for code that is new in 4.13. It's
        roughly half older bugs, with fixes going to stable, and half
        fixes/updates for Power9.
      
        Thanks to: Aneesh Kumar K.V, Anton Blanchard, Balbir Singh, Benjamin
        Herrenschmidt, Madhavan Srinivasan, Michael Neuling, Nicholas Piggin,
        Oliver O'Halloran"
      
      * tag 'powerpc-4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
        powerpc/64: Fix atomic64_inc_not_zero() to return an int
        powerpc: Fix emulation of mfocrf in emulate_step()
        powerpc: Fix emulation of mcrf in emulate_step()
        powerpc/perf: Add POWER9 alternate PM_RUN_CYC and PM_RUN_INST_CMPL events
        powerpc/perf: Fix SDAR_MODE value for continous sampling on Power9
        powerpc/asm: Mark cr0 as clobbered in mftb()
        powerpc/powernv: Fix local TLB flush for boot and MCE on POWER9
        powerpc/mm/radix: Synchronize updates to the process table
        powerpc/mm/radix: Properly clear process table entry
        powerpc/powernv: Tell OPAL about our MMU mode on POWER9
        powerpc/kexec: Fix radix to hash kexec due to IAMR/AMOR
      deed9deb
    • Luis R. Rodriguez's avatar
      kmod: throttle kmod thread limit · 6d7964a7
      Luis R. Rodriguez authored
      If we reach the limit of modprobe_limit threads running the next
      request_module() call will fail.  The original reason for adding a kill
      was to do away with possible issues with in old circumstances which would
      create a recursive series of request_module() calls.
      
      We can do better than just be super aggressive and reject calls once we've
      reached the limit by simply making pending callers wait until the
      threshold has been reduced, and then throttling them in, one by one.
      
      This throttling enables requests over the kmod concurrent limit to be
      processed once a pending request completes.  Only the first item queued up
      to wait is woken up.  The assumption here is once a task is woken it will
      have no other option to also kick the queue to check if there are more
      pending tasks -- regardless of whether or not it was successful.
      
      By throttling and processing only max kmod concurrent tasks we ensure we
      avoid unexpected fatal request_module() calls, and we keep memory
      consumption on module loading to a minimum.
      
      With x86_64 qemu, with 4 cores, 4 GiB of RAM it takes the following run
      time to run both tests:
      
      time ./kmod.sh -t 0008
      real    0m16.366s
      user    0m0.883s
      sys     0m8.916s
      
      time ./kmod.sh -t 0009
      real    0m50.803s
      user    0m0.791s
      sys     0m9.852s
      
      Link: http://lkml.kernel.org/r/20170628223155.26472-4-mcgrof@kernel.orgSigned-off-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
      Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Jessica Yu <jeyu@redhat.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Michal Marek <mmarek@suse.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6d7964a7
    • Luis R. Rodriguez's avatar
      kmod: add test driver to stress test the module loader · d9c6a72d
      Luis R. Rodriguez authored
      This adds a new stress test driver for kmod: the kernel module loader.
      The new stress test driver, test_kmod, is only enabled as a module right
      now.  It should be possible to load this as built-in and load tests
      early (refer to the force_init_test module parameter), however since a
      lot of test can get a system out of memory fast we leave this disabled
      for now.
      
      Using a system with 1024 MiB of RAM can *easily* get your kernel OOM
      fast with this test driver.
      
      The test_kmod driver exposes API knobs for us to fine tune simple
      request_module() and get_fs_type() calls.  Since these API calls only
      allow each one parameter a test driver for these is rather simple.
      Other factors that can help out test driver though are the number of
      calls we issue and knowing current limitations of each.  This exposes
      configuration as much as possible through userspace to be able to build
      tests directly from userspace.
      
      Since it allows multiple misc devices its will eventually (once we add a
      knob to let us create new devices at will) also be possible to perform
      more tests in parallel, provided you have enough memory.
      
      We only enable tests we know work as of right now.
      
      Demo screenshots:
      
       # tools/testing/selftests/kmod/kmod.sh
      kmod_test_0001_driver: OK! - loading kmod test
      kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
      kmod_test_0001_fs: OK! - loading kmod test
      kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
      kmod_test_0002_driver: OK! - loading kmod test
      kmod_test_0002_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
      kmod_test_0002_fs: OK! - loading kmod test
      kmod_test_0002_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
      kmod_test_0003: OK! - loading kmod test
      kmod_test_0003: OK! - Return value: 0 (SUCCESS), expected SUCCESS
      kmod_test_0004: OK! - loading kmod test
      kmod_test_0004: OK! - Return value: 0 (SUCCESS), expected SUCCESS
      kmod_test_0005: OK! - loading kmod test
      kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
      kmod_test_0006: OK! - loading kmod test
      kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
      kmod_test_0005: OK! - loading kmod test
      kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
      kmod_test_0006: OK! - loading kmod test
      kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
      XXX: add test restult for 0007
      Test completed
      
      You can also request for specific tests:
      
       # tools/testing/selftests/kmod/kmod.sh -t 0001
      kmod_test_0001_driver: OK! - loading kmod test
      kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
      kmod_test_0001_fs: OK! - loading kmod test
      kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
      Test completed
      
      Lastly, the current available number of tests:
      
       # tools/testing/selftests/kmod/kmod.sh --help
      Usage: tools/testing/selftests/kmod/kmod.sh [ -t <4-number-digit> ]
      Valid tests: 0001-0009
      
      0001 - Simple test - 1 thread  for empty string
      0002 - Simple test - 1 thread  for modules/filesystems that do not exist
      0003 - Simple test - 1 thread  for get_fs_type() only
      0004 - Simple test - 2 threads for get_fs_type() only
      0005 - multithreaded tests with default setup - request_module() only
      0006 - multithreaded tests with default setup - get_fs_type() only
      0007 - multithreaded tests with default setup test request_module() and get_fs_type()
      0008 - multithreaded - push kmod_concurrent over max_modprobes for request_module()
      0009 - multithreaded - push kmod_concurrent over max_modprobes for get_fs_type()
      
      The following test cases currently fail, as such they are not currently
      enabled by default:
      
       # tools/testing/selftests/kmod/kmod.sh -t 0008
       # tools/testing/selftests/kmod/kmod.sh -t 0009
      
      To be sure to run them as intended please unload both of the modules:
      
        o test_module
        o xfs
      
      And ensure they are not loaded on your system prior to testing them.  If
      you use these paritions for your rootfs you can change the default test
      driver used for get_fs_type() by exporting it into your environment.  For
      example of other test defaults you can override refer to kmod.sh
      allow_user_defaults().
      
      Behind the scenes this is how we fine tune at a test case prior to
      hitting a trigger to run it:
      
      cat /sys/devices/virtual/misc/test_kmod0/config
      echo -n "2" > /sys/devices/virtual/misc/test_kmod0/config_test_case
      echo -n "ext4" > /sys/devices/virtual/misc/test_kmod0/config_test_fs
      echo -n "80" > /sys/devices/virtual/misc/test_kmod0/config_num_threads
      cat /sys/devices/virtual/misc/test_kmod0/config
      echo -n "1" > /sys/devices/virtual/misc/test_kmod0/config_num_threads
      
      Finally to trigger:
      
      echo -n "1" > /sys/devices/virtual/misc/test_kmod0/trigger_config
      
      The kmod.sh script uses the above constructs to build different test cases.
      
      A bit of interpretation of the current failures follows, first two
      premises:
      
      a) When request_module() is used userspace figures out an optimized
         version of module order for us.  Once it finds the modules it needs, as
         per depmod symbol dep map, it will finit_module() the respective
         modules which are needed for the original request_module() request.
      
      b) We have an optimization in place whereby if a kernel uses
         request_module() on a module already loaded we never bother userspace
         as the module already is loaded.  This is all handled by kernel/kmod.c.
      
      A few things to consider to help identify root causes of issues:
      
      0) kmod 19 has a broken heuristic for modules being assumed to be
         built-in to your kernel and will return 0 even though request_module()
         failed.  Upgrade to a newer version of kmod.
      
      1) A get_fs_type() call for "xfs" will request_module() for "fs-xfs",
         not for "xfs".  The optimization in kernel described in b) fails to
         catch if we have a lot of consecutive get_fs_type() calls.  The reason
         is the optimization in place does not look for aliases.  This means two
         consecutive get_fs_type() calls will bump kmod_concurrent, whereas
         request_module() will not.
      
      This one explanation why test case 0009 fails at least once for
      get_fs_type().
      
      2) If a module fails to load --- for whatever reason (kmod_concurrent
         limit reached, file not yet present due to rootfs switch, out of
         memory) we have a period of time during which module request for the
         same name either with request_module() or get_fs_type() will *also*
         fail to load even if the file for the module is ready.
      
      This explains why *multiple* NULLs are possible on test 0009.
      
      3) finit_module() consumes quite a bit of memory.
      
      4) Filesystems typically also have more dependent modules than other
         modules, its important to note though that even though a get_fs_type()
         call does not incur additional kmod_concurrent bumps, since userspace
         loads dependencies it finds it needs via finit_module_fd(), it *will*
         take much more memory to load a module with a lot of dependencies.
      
      Because of 3) and 4) we will easily run into out of memory failures with
      certain tests.  For instance test 0006 fails on qemu with 1024 MiB of RAM.
      It panics a box after reaping all userspace processes and still not
      having enough memory to reap.
      
      [arnd@arndb.de: add dependencies for test module]
        Link: http://lkml.kernel.org/r/20170630154834.3689272-1-arnd@arndb.de
      Link: http://lkml.kernel.org/r/20170628223155.26472-3-mcgrof@kernel.orgSigned-off-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
      Cc: Jessica Yu <jeyu@redhat.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Michal Marek <mmarek@suse.com>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d9c6a72d
    • Luis R. Rodriguez's avatar
      MAINTAINERS: give kmod some maintainer love · 062b8740
      Luis R. Rodriguez authored
      As suggested by Jessica, I've been actively working on kmod, so might as
      well reflect its maintained status.
      
      Changes are expected to go through akpm's tree.
      
      Link: http://lkml.kernel.org/r/20170628223155.26472-2-mcgrof@kernel.orgSigned-off-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
      Suggested-by: default avatarJessica Yu <jeyu@redhat.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Michal Marek <mmarek@suse.com>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      062b8740
    • Tobias Klauser's avatar
      xtensa: use generic fb.h · 20cf0c54
      Tobias Klauser authored
      The arch uses a verbatim copy of the asm-generic version and does not
      add any own implementations to the header, so use asm-generic/fb.h
      instead of duplicating code.
      
      Link: http://lkml.kernel.org/r/20170517083545.2115-1-tklauser@distanz.chSigned-off-by: default avatarTobias Klauser <tklauser@distanz.ch>
      Acked-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      20cf0c54
    • Akinobu Mita's avatar
      fault-inject: add /proc/<pid>/fail-nth · 168c42bc
      Akinobu Mita authored
      fail-nth interface is only created in /proc/self/task/<current-tid>/.
      This change also adds it in /proc/<pid>/.
      
      This makes shell based tool a bit simpler.
      
      	$ bash -c "builtin echo 100 > /proc/self/fail-nth && exec ls /"
      
      Link: http://lkml.kernel.org/r/1491490561-10485-6-git-send-email-akinobu.mita@gmail.comSigned-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      168c42bc
    • Akinobu Mita's avatar
      fault-inject: simplify access check for fail-nth · 1203c8e6
      Akinobu Mita authored
      The fail-nth file is created with 0666 and the access is permitted if
      and only if the task is current.
      
      This file is owned by the currnet user.  So we can create it with 0644
      and allow the owner to write it.  This enables to watch the status of
      task->fail_nth from another processes.
      
      [akinobu.mita@gmail.com: don't convert unsigned type value as signed int]
        Link: http://lkml.kernel.org/r/1492444483-9239-1-git-send-email-akinobu.mita@gmail.com
      [akinobu.mita@gmail.com: avoid unwanted data race to task->fail_nth]
        Link: http://lkml.kernel.org/r/1499962492-8931-1-git-send-email-akinobu.mita@gmail.com
      Link: http://lkml.kernel.org/r/1491490561-10485-5-git-send-email-akinobu.mita@gmail.comSigned-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Acked-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1203c8e6
    • Akinobu Mita's avatar
      fault-inject: make fail-nth read/write interface symmetric · bfc74093
      Akinobu Mita authored
      The read interface for fail-nth looks a bit odd.  Read from this file
      returns "NYYYY..." or "YYYYY..." (this makes me surprise when cat this
      file).  Because there is no EOF condition.  The first character
      indicates current->fail_nth is zero or not, and then current->fail_nth
      is reset to zero.
      
      Just returning task->fail_nth value is more natural to understand.
      
      Link: http://lkml.kernel.org/r/1491490561-10485-4-git-send-email-akinobu.mita@gmail.comSigned-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bfc74093
    • Akinobu Mita's avatar
      fault-inject: parse as natural 1-based value for fail-nth write interface · 9049f2f6
      Akinobu Mita authored
      The value written to fail-nth file is parsed as 0-based.  Parsing as
      one-based is more natural to understand and it enables to cancel the
      previous setup by simply writing '0'.
      
      This change also converts task->fail_nth from signed to unsigned int.
      
      Link: http://lkml.kernel.org/r/1491490561-10485-3-git-send-email-akinobu.mita@gmail.comSigned-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9049f2f6
    • Akinobu Mita's avatar
      fault-inject: automatically detect the number base for fail-nth write interface · ecaad81c
      Akinobu Mita authored
      Automatically detect the number base to use when writing to fail-nth
      file instead of always parsing as a decimal number.
      
      Link: http://lkml.kernel.org/r/1491490561-10485-2-git-send-email-akinobu.mita@gmail.comSigned-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ecaad81c
    • Kefeng Wang's avatar
      kernel/watchdog.c: use better pr_fmt prefix · 5f92a7b0
      Kefeng Wang authored
      After commit 73ce0511 ("kernel/watchdog.c: move hardlockup
      detector to separate file"), 'NMI watchdog' is inappropriate in
      kernel/watchdog.c, using 'watchdog' only.
      
      Link: http://lkml.kernel.org/r/1499928642-48983-1-git-send-email-wangkefeng.wang@huawei.comSigned-off-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
      Cc: Babu Moger <babu.moger@oracle.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5f92a7b0
    • Luis de Bethencourt's avatar
      5624a8b0
    • Michael Ellerman's avatar
      lib/atomic64_test.c: add a test that atomic64_inc_not_zero() returns an int · ffba19cc
      Michael Ellerman authored
      atomic64_inc_not_zero() returns a "truth value" which in C is
      traditionally an int.  That means callers are likely to expect the
      result will fit in an int.
      
      If an implementation returns a "true" value which does not fit in an
      int, then there's a possibility that callers will truncate it when they
      store it in an int.
      
      In fact this happened in practice, see commit 966d2b04
      ("percpu-refcount: fix reference leak during percpu-atomic transition").
      
      So add a test that the result fits in an int, even when the input
      doesn't.  This catches the case where an implementation just passes the
      non-zero input value out as the result.
      
      Link: http://lkml.kernel.org/r/1499775133-1231-1-git-send-email-mpe@ellerman.id.auSigned-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Cc: Douglas Miller <dougmill@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ffba19cc