28 Nov, 2017

1 commit

  • This is a pure automated search-and-replace of the internal kernel
    superblock flags.

    The s_flags are now called SB_*, with the names and the values for the
    moment mirroring the MS_* flags that they're equivalent to.

    Note how the MS_xyz flags are the ones passed to the mount system call,
    while the SB_xyz flags are what we then use in sb->s_flags.

    The script to do this was:

    # places to look in; re security/*: it generally should *not* be
    # touched (that stuff parses mount(2) arguments directly), but
    # there are two places where we really deal with superblock flags.
    FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
    include/linux/fs.h include/uapi/linux/bfs_fs.h \
    security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
    # the list of MS_... constants
    SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
    DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
    POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
    I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
    ACTIVE NOUSER"

    SED_PROG=
    for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done

    # we want files that contain at least one of MS_...,
    # with fs/namespace.c and fs/pnode.c excluded.
    L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')

    for f in $L; do sed -i $f $SED_PROG; done

    Requested-by: Al Viro
    Signed-off-by: Linus Torvalds

    Linus Torvalds
     

18 Nov, 2017

6 commits

  • Merge more updates from Andrew Morton:

    - a bit more MM

    - procfs updates

    - dynamic-debug fixes

    - lib/ updates

    - checkpatch

    - epoll

    - nilfs2

    - signals

    - rapidio

    - PID management cleanup and optimization

    - kcov updates

    - sysvipc updates

    - quite a few misc things all over the place

    * emailed patches from Andrew Morton : (94 commits)
    EXPERT Kconfig menu: fix broken EXPERT menu
    include/asm-generic/topology.h: remove unused parent_node() macro
    arch/tile/include/asm/topology.h: remove unused parent_node() macro
    arch/sparc/include/asm/topology_64.h: remove unused parent_node() macro
    arch/sh/include/asm/topology.h: remove unused parent_node() macro
    arch/ia64/include/asm/topology.h: remove unused parent_node() macro
    drivers/pcmcia/sa1111_badge4.c: avoid unused function warning
    mm: add infrastructure for get_user_pages_fast() benchmarking
    sysvipc: make get_maxid O(1) again
    sysvipc: properly name ipc_addid() limit parameter
    sysvipc: duplicate lock comments wrt ipc_addid()
    sysvipc: unteach ids->next_id for !CHECKPOINT_RESTORE
    initramfs: use time64_t timestamps
    drivers/watchdog: make use of devm_register_reboot_notifier()
    kernel/reboot.c: add devm_register_reboot_notifier()
    kcov: update documentation
    Makefile: support flag -fsanitizer-coverage=trace-cmp
    kcov: support comparison operands collection
    kcov: remove pointless current != NULL check
    kernel/panic.c: add TAINT_AUX
    ...

    Linus Torvalds
     
  • For a custom microbenchmark on a 3.30GHz Xeon SandyBridge, which calls
    IPC_STAT over and over, it was calculated that, on avg the cost of
    ipc_get_maxid() for increasing amounts of keys was:

    10 keys: ~900 cycles
    100 keys: ~15000 cycles
    1000 keys: ~150000 cycles
    10000 keys: ~2100000 cycles

    This is unsurprising as maxid is currently O(n).

    By having the max_id available in O(1) we save all those cycles for each
    semctl(_STAT) command, the idr_find can be expensive -- which some real
    (customer) workloads actually poll on.

    Note that this used to be the case, until commit 7ca7e564e04 ("ipc:
    store ipcs into IDRs"). The cost is the extra idr_find when doing
    RMIDs, but we simply go backwards, and should not take too many
    iterations to find the new value.

    [akpm@linux-foundation.org: coding-style fixes]
    Link: http://lkml.kernel.org/r/20170831172049.14576-5-dave@stgolabs.net
    Signed-off-by: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • This is better understood as a limit, instead of size; exactly like the
    function comment indicates. Rename it.

    Link: http://lkml.kernel.org/r/20170831172049.14576-4-dave@stgolabs.net
    Signed-off-by: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • The comment in msgqueues when using ipc_addid() is quite useful imo.
    Duplicate it for shm and semaphores.

    Link: http://lkml.kernel.org/r/20170831172049.14576-3-dave@stgolabs.net
    Signed-off-by: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Patch series "sysvipc: ipc-key management improvements".

    Here are a few improvements I spotted while eyeballing Guillaume's
    rhashtable implementation for ipc keys. The first and fourth patches
    are the interesting ones, the middle two are trivial.

    This patch (of 4):

    The next_id object-allocation functionality was introduced in commit
    03f595668017 ("ipc: add sysctl to specify desired next object id").

    Given that these new entries are _only_ exported under the
    CONFIG_CHECKPOINT_RESTORE option, there is no point for the common case
    to even know about ->next_id. As such rewrite ipc_buildid() such that
    it can do away with the field as well as unnecessary branches when
    adding a new identifier. The end result also better differentiates both
    cases, so the code ends up being cleaner; albeit the small duplications
    regarding the default case.

    [akpm@linux-foundation.org: coding-style fixes]
    Link: http://lkml.kernel.org/r/20170831172049.14576-2-dave@stgolabs.net
    Signed-off-by: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Pull misc vfs updates from Al Viro:
    "Assorted stuff, really no common topic here"

    * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
    vfs: grab the lock instead of blocking in __fd_install during resizing
    vfs: stop clearing close on exec when closing a fd
    include/linux/fs.h: fix comment about struct address_space
    fs: make fiemap work from compat_ioctl
    coda: fix 'kernel memory exposure attempt' in fsync
    pstore: remove unneeded unlikely()
    vfs: remove unneeded unlikely()
    stubs for mount_bdev() and kill_block_super() in !CONFIG_BLOCK case
    make vfs_ustat() static
    do_handle_open() should be static
    elf_fdpic: fix unused variable warning
    fold destroy_super() into __put_super()
    new helper: destroy_unused_super()
    fix address space warnings in ipc/
    acct.h: get rid of detritus

    Linus Torvalds
     

02 Nov, 2017

1 commit

  • Many source files in the tree are missing licensing information, which
    makes it harder for compliance tools to determine the correct license.

    By default all files without license information are under the default
    license of the kernel, which is GPL version 2.

    Update the files which contain no license information with the 'GPL-2.0'
    SPDX license identifier. The SPDX identifier is a legally binding
    shorthand, which can be used instead of the full boiler plate text.

    This patch is based on work done by Thomas Gleixner and Kate Stewart and
    Philippe Ombredanne.

    How this work was done:

    Patches were generated and checked against linux-4.14-rc6 for a subset of
    the use cases:
    - file had no licensing information it it.
    - file was a */uapi/* one with no licensing information in it,
    - file was a */uapi/* one with existing licensing information,

    Further patches will be generated in subsequent months to fix up cases
    where non-standard license headers were used, and references to license
    had to be inferred by heuristics based on keywords.

    The analysis to determine which SPDX License Identifier to be applied to
    a file was done in a spreadsheet of side by side results from of the
    output of two independent scanners (ScanCode & Windriver) producing SPDX
    tag:value files created by Philippe Ombredanne. Philippe prepared the
    base worksheet, and did an initial spot review of a few 1000 files.

    The 4.13 kernel was the starting point of the analysis with 60,537 files
    assessed. Kate Stewart did a file by file comparison of the scanner
    results in the spreadsheet to determine which SPDX license identifier(s)
    to be applied to the file. She confirmed any determination that was not
    immediately clear with lawyers working with the Linux Foundation.

    Criteria used to select files for SPDX license identifier tagging was:
    - Files considered eligible had to be source code files.
    - Make and config files were included as candidates if they contained >5
    lines of source
    - File already had some variant of a license header in it (even if
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

12 Oct, 2017

1 commit


26 Sep, 2017

1 commit


21 Sep, 2017

1 commit

  • Commit 553f770ef71b ("ipc: move compat shmctl to native") moved the
    compat IPC syscall handling into ipc/shm.c and refactored the struct
    accessors in the process. Unfortunately, the call to
    copy_compat_shmid_to_user when handling a compat {IPC,SHM}_STAT command
    gets the arguments the wrong way round, passing a kernel stack address
    as the user buffer (destination) and the user buffer as the kernel stack
    address (source).

    This patch fixes the parameter ordering so the buffers are accessed
    correctly.

    Cc: Al Viro
    Cc: Andrew Morton
    Signed-off-by: Will Deacon
    Signed-off-by: Al Viro

    Will Deacon
     

15 Sep, 2017

1 commit

  • Pull ipc compat cleanup and 64-bit time_t from Al Viro:
    "IPC copyin/copyout sanitizing, including 64bit time_t work from Deepa
    Dinamani"

    * 'work.ipc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
    utimes: Make utimes y2038 safe
    ipc: shm: Make shmid_kernel timestamps y2038 safe
    ipc: sem: Make sem_array timestamps y2038 safe
    ipc: msg: Make msg_queue timestamps y2038 safe
    ipc: mqueue: Replace timespec with timespec64
    ipc: Make sys_semtimedop() y2038 safe
    get rid of SYSVIPC_COMPAT on ia64
    semtimedop(): move compat to native
    shmat(2): move compat to native
    msgrcv(2), msgsnd(2): move compat to native
    ipc(2): move compat to native
    ipc: make use of compat ipc_perm helpers
    semctl(): move compat to native
    semctl(): separate all layout-dependent copyin/copyout
    msgctl(): move compat to native
    msgctl(): split the actual work from copyin/copyout
    ipc: move compat shmctl to native
    shmctl: split the work from copyin/copyout

    Linus Torvalds
     

09 Sep, 2017

6 commits

  • ipc_findkey() used to scan all objects to look for the wanted key. This
    is slow when using a high number of keys. This change adds an rhashtable
    of kern_ipc_perm objects in ipc_ids, so that one lookup cease to be O(n).

    This change gives a 865% improvement of benchmark reaim.jobs_per_min on a
    56 threads Intel(R) Xeon(R) CPU E5-2695 v3 @ 2.30GHz with 256G memory [1]

    Other (more micro) benchmark results, by the author: On an i5 laptop, the
    following loop executed right after a reboot took, without and with this
    change:

    for (int i = 0, k=0x424242; i < KEYS; ++i)
    semget(k++, 1, IPC_CREAT | 0600);

    total total max single max single
    KEYS without with call without call with

    1 3.5 4.9 µs 3.5 4.9
    10 7.6 8.6 µs 3.7 4.7
    32 16.2 15.9 µs 4.3 5.3
    100 72.9 41.8 µs 3.7 4.7
    1000 5,630.0 502.0 µs * *
    10000 1,340,000.0 7,240.0 µs * *
    31900 17,600,000.0 22,200.0 µs * *

    *: unreliable measure: high variance

    The duration for a lookup-only usage was obtained by the same loop once
    the keys are present:

    total total max single max single
    KEYS without with call without call with

    1 2.1 2.5 µs 2.1 2.5
    10 4.5 4.8 µs 2.2 2.3
    32 13.0 10.8 µs 2.3 2.8
    100 82.9 25.1 µs * 2.3
    1000 5,780.0 217.0 µs * *
    10000 1,470,000.0 2,520.0 µs * *
    31900 17,400,000.0 7,810.0 µs * *

    Finally, executing each semget() in a new process gave, when still
    summing only the durations of these syscalls:

    creation:
    total total
    KEYS without with

    1 3.7 5.0 µs
    10 32.9 36.7 µs
    32 125.0 109.0 µs
    100 523.0 353.0 µs
    1000 20,300.0 3,280.0 µs
    10000 2,470,000.0 46,700.0 µs
    31900 27,800,000.0 219,000.0 µs

    lookup-only:
    total total
    KEYS without with

    1 2.5 2.7 µs
    10 25.4 24.4 µs
    32 106.0 72.6 µs
    100 591.0 352.0 µs
    1000 22,400.0 2,250.0 µs
    10000 2,510,000.0 25,700.0 µs
    31900 28,200,000.0 115,000.0 µs

    [1] http://lkml.kernel.org/r/20170814060507.GE23258@yexl-desktop

    Link: http://lkml.kernel.org/r/20170815194954.ck32ta2z35yuzpwp@debix
    Signed-off-by: Guillaume Knispel
    Reviewed-by: Marc Pardo
    Cc: Davidlohr Bueso
    Cc: Kees Cook
    Cc: Manfred Spraul
    Cc: Alexey Dobriyan
    Cc: "Eric W. Biederman"
    Cc: "Peter Zijlstra (Intel)"
    Cc: Ingo Molnar
    Cc: Sebastian Andrzej Siewior
    Cc: Serge Hallyn
    Cc: Andrey Vagin
    Cc: Guillaume Knispel
    Cc: Marc Pardo
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Guillaume Knispel
     
  • Replacing semop()'s kmalloc for kvmalloc was originally proposed by
    Manfred on the premise that it can be called for large (than order-1)
    sizes. For example, while Oracle recommends setting SEMOPM to a _minimum_
    of 100, some distros[1] encourage the setting to be a factor of the amount
    of db tasks (PROCESSES), which can get fishy for large systems (easily
    going beyond 1000).

    [1] An Example of Semaphore Settings
    https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Tuning_and_Optimizing_Red_Hat_Enterprise_Linux_for_Oracle_9i_and_10g_Databases/sect-Oracle_9i_and_10g_Tuning_Guide-Setting_Semaphores-An_Example_of_Semaphore_Settings.html

    So let's just convert this to kvmalloc, just like the rest of the
    allocations we do in ipc. While the fallback vmalloc obviously involves
    more overhead, this by far the uncommon path, and it's better for the user
    than just erroring out with kmalloc.

    Link: http://lkml.kernel.org/r/20170803184136.13855-2-dave@stgolabs.net
    Signed-off-by: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • ... 'tis not used.

    Link: http://lkml.kernel.org/r/20170803184136.13855-1-dave@stgolabs.net
    Signed-off-by: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • refcount_t type and corresponding API should be used instead of atomic_t
    when the variable is used as a reference counter. This allows to avoid
    accidental refcounter overflows that might lead to use-after-free
    situations.

    Link: http://lkml.kernel.org/r/1499417992-3238-4-git-send-email-elena.reshetova@intel.com
    Signed-off-by: Elena Reshetova
    Signed-off-by: Hans Liljestrand
    Signed-off-by: Kees Cook
    Signed-off-by: David Windsor
    Cc: Peter Zijlstra
    Cc: Greg Kroah-Hartman
    Cc: "Eric W. Biederman"
    Cc: Ingo Molnar
    Cc: Alexey Dobriyan
    Cc: Serge Hallyn
    Cc:
    Cc: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Elena Reshetova
     
  • refcount_t type and corresponding API should be used instead of atomic_t
    when the variable is used as a reference counter. This allows to avoid
    accidental refcounter overflows that might lead to use-after-free
    situations.

    Link: http://lkml.kernel.org/r/1499417992-3238-3-git-send-email-elena.reshetova@intel.com
    Signed-off-by: Elena Reshetova
    Signed-off-by: Hans Liljestrand
    Signed-off-by: Kees Cook
    Signed-off-by: David Windsor
    Cc: Peter Zijlstra
    Cc: Greg Kroah-Hartman
    Cc: "Eric W. Biederman"
    Cc: Ingo Molnar
    Cc: Alexey Dobriyan
    Cc: Serge Hallyn
    Cc:
    Cc: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Elena Reshetova
     
  • refcount_t type and corresponding API should be used instead of atomic_t
    when the variable is used as a reference counter. This allows to avoid
    accidental refcounter overflows that might lead to use-after-free
    situations.

    Link: http://lkml.kernel.org/r/1499417992-3238-2-git-send-email-elena.reshetova@intel.com
    Signed-off-by: Elena Reshetova
    Signed-off-by: Hans Liljestrand
    Signed-off-by: Kees Cook
    Signed-off-by: David Windsor
    Cc: Peter Zijlstra
    Cc: Greg Kroah-Hartman
    Cc: "Eric W. Biederman"
    Cc: Ingo Molnar
    Cc: Alexey Dobriyan
    Cc: Serge Hallyn
    Cc:
    Cc: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Elena Reshetova
     

04 Sep, 2017

5 commits

  • time_t is not y2038 safe. Replace all uses of
    time_t by y2038 safe time64_t.

    Similarly, replace the calls to get_seconds() with
    y2038 safe ktime_get_real_seconds().
    Note that this preserves fast access on 64 bit systems,
    but 32 bit systems need sequence counters.

    The syscall interfaces themselves are not changed as part of
    the patch. They will be part of a different series.

    Signed-off-by: Deepa Dinamani
    Reviewed-by: Arnd Bergmann
    Signed-off-by: Al Viro

    Deepa Dinamani
     
  • time_t is not y2038 safe. Replace all uses of
    time_t by y2038 safe time64_t.

    Similarly, replace the calls to get_seconds() with
    y2038 safe ktime_get_real_seconds().
    Note that this preserves fast access on 64 bit systems,
    but 32 bit systems need sequence counters.

    The syscall interface themselves are not changed as part of
    the patch. They will be part of a different series.

    Signed-off-by: Deepa Dinamani
    Reviewed-by: Arnd Bergmann
    Signed-off-by: Al Viro

    Deepa Dinamani
     
  • time_t is not y2038 safe. Replace all uses of
    time_t by y2038 safe time64_t.

    Similarly, replace the calls to get_seconds() with
    y2038 safe ktime_get_real_seconds().
    Note that this preserves fast access on 64 bit systems,
    but 32 bit systems need sequence counters.

    The syscall interfaces themselves are not changed as part of
    the patch. They will be part of a different series.

    Signed-off-by: Deepa Dinamani
    Reviewed-by: Arnd Bergmann
    Signed-off-by: Al Viro

    Deepa Dinamani
     
  • struct timespec is not y2038 safe. Replace
    all uses of timespec by y2038 safe struct timespec64.

    Even though timespec is used here to represent timeouts,
    replace these with timespec64 so that it facilitates
    in verification by creating a y2038 safe kernel image
    that is free of timespec.

    The syscall interfaces themselves are not changed as part
    of the patch. They will be part of a different series.

    Signed-off-by: Deepa Dinamani
    Cc: Paul Moore
    Cc: Richard Guy Briggs
    Reviewed-by: Richard Guy Briggs
    Reviewed-by: Arnd Bergmann
    Acked-by: Paul Moore
    Signed-off-by: Al Viro

    Deepa Dinamani
     
  • struct timespec is not y2038 safe on 32 bit machines.
    Replace timespec with y2038 safe struct timespec64.

    Note that the patch only changes the internals without
    modifying the syscall interface. This will be part
    of a separate series.

    Signed-off-by: Deepa Dinamani
    Reviewed-by: Arnd Bergmann
    Signed-off-by: Al Viro

    Deepa Dinamani
     

21 Aug, 2017

1 commit


17 Aug, 2017

1 commit

  • There is no agreed-upon definition of spin_unlock_wait()'s semantics,
    and it appears that all callers could do just as well with a lock/unlock
    pair. This commit therefore replaces the spin_unlock_wait() call in
    exit_sem() with spin_lock() followed immediately by spin_unlock().
    This should be safe from a performance perspective because exit_sem()
    is rarely invoked in production.

    Signed-off-by: Paul E. McKenney
    Cc: Andrew Morton
    Cc: Davidlohr Bueso
    Cc: Will Deacon
    Cc: Peter Zijlstra
    Cc: Alan Stern
    Cc: Andrea Parri
    Cc: Linus Torvalds
    Acked-by: Manfred Spraul

    Paul E. McKenney
     

03 Aug, 2017

1 commit

  • When building with the randstruct gcc plugin, the layout of the IPC
    structs will be randomized, which requires any sub-structure accesses to
    use container_of(). The proc display handlers were missing the needed
    container_of()s since the iterator is passing in the top-level struct
    kern_ipc_perm.

    This would lead to crashes when running the "lsipc" program after the
    system had IPC registered (e.g. after starting up Gnome):

    general protection fault: 0000 [#1] PREEMPT SMP
    ...
    RIP: 0010:shm_add_rss_swap.isra.1+0x13/0xa0
    ...
    Call Trace:
    sysvipc_shm_proc_show+0x5e/0x150
    sysvipc_proc_show+0x1a/0x30
    seq_read+0x2e9/0x3f0
    ...

    Link: http://lkml.kernel.org/r/20170730205950.GA55841@beast
    Fixes: 3859a271a003 ("randstruct: Mark various structs for randomization")
    Signed-off-by: Kees Cook
    Reported-by: Dominik Brodowski
    Acked-by: Davidlohr Bueso
    Acked-by: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kees Cook
     

16 Jul, 2017

11 commits


13 Jul, 2017

3 commits

  • Now that ipc_rcu_alloc() and ipc_rcu_free() are removed, document when
    it is valid to use ipc_getref() and ipc_putref().

    Link: http://lkml.kernel.org/r/20170525185107.12869-21-manfred@colorfullife.com
    Signed-off-by: Manfred Spraul
    Cc: Davidlohr Bueso
    Cc: Kees Cook
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Manfred Spraul
     
  • The remaining users of __sem_free() can simply call kvfree() instead for
    better readability.

    [manfred@colorfullife.com: Rediff to keep rcu protection for security_sem_alloc()]
    Link: http://lkml.kernel.org/r/20170525185107.12869-20-manfred@colorfullife.com
    Signed-off-by: Kees Cook
    Signed-off-by: Manfred Spraul
    Cc: Davidlohr Bueso
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kees Cook
     
  • There is nothing special about the msg_alloc/free routines any more, so
    remove them to make code more readable.

    [manfred@colorfullife.com: Rediff to keep rcu protection for security_msg_queue_alloc()]
    Link: http://lkml.kernel.org/r/20170525185107.12869-19-manfred@colorfullife.com
    Signed-off-by: Kees Cook
    Signed-off-by: Manfred Spraul
    Cc: Davidlohr Bueso
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kees Cook