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
     

09 May, 2016

1 commit


15 Jan, 2016

1 commit

  • Mark those kmem allocations that are known to be easily triggered from
    userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
    memcg. For the list, see below:

    - threadinfo
    - task_struct
    - task_delay_info
    - pid
    - cred
    - mm_struct
    - vm_area_struct and vm_region (nommu)
    - anon_vma and anon_vma_chain
    - signal_struct
    - sighand_struct
    - fs_struct
    - files_struct
    - fdtable and fdtable->full_fds_bits
    - dentry and external_name
    - inode for all filesystems. This is the most tedious part, because
    most filesystems overwrite the alloc_inode method.

    The list is far from complete, so feel free to add more objects.
    Nevertheless, it should be close to "account everything" approach and
    keep most workloads within bounds. Malevolent users will be able to
    breach the limit, but this was possible even with the former "account
    everything" approach (simply because it did not account everything in
    fact).

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Vladimir Davydov
    Acked-by: Johannes Weiner
    Acked-by: Michal Hocko
    Cc: Tejun Heo
    Cc: Greg Thelen
    Cc: Christoph Lameter
    Cc: Pekka Enberg
    Cc: David Rientjes
    Cc: Joonsoo Kim
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Vladimir Davydov
     

09 Dec, 2015

1 commit

  • kmap() in page_follow_link_light() needed to go - allowing to hold
    an arbitrary number of kmaps for long is a great way to deadlocking
    the system.

    new helper (inode_nohighmem(inode)) needs to be used for pagecache
    symlinks inodes; done for all in-tree cases. page_follow_link_light()
    instrumented to yell about anything missed.

    Signed-off-by: Al Viro

    Al Viro
     

13 Mar, 2014

1 commit

  • Previously, the no-op "mount -o mount /dev/xxx" operation when the
    file system is already mounted read-write causes an implied,
    unconditional syncfs(). This seems pretty stupid, and it's certainly
    documented or guaraunteed to do this, nor is it particularly useful,
    except in the case where the file system was mounted rw and is getting
    remounted read-only.

    However, it's possible that there might be some file systems that are
    actually depending on this behavior. In most file systems, it's
    probably fine to only call sync_filesystem() when transitioning from
    read-write to read-only, and there are some file systems where this is
    not needed at all (for example, for a pseudo-filesystem or something
    like romfs).

    Signed-off-by: "Theodore Ts'o"
    Cc: linux-fsdevel@vger.kernel.org
    Cc: Christoph Hellwig
    Cc: Artem Bityutskiy
    Cc: Adrian Hunter
    Cc: Evgeniy Dushistov
    Cc: Jan Kara
    Cc: OGAWA Hirofumi
    Cc: Anders Larsen
    Cc: Phillip Lougher
    Cc: Kees Cook
    Cc: Mikulas Patocka
    Cc: Petr Vandrovec
    Cc: xfs@oss.sgi.com
    Cc: linux-btrfs@vger.kernel.org
    Cc: linux-cifs@vger.kernel.org
    Cc: samba-technical@lists.samba.org
    Cc: codalist@coda.cs.cmu.edu
    Cc: linux-ext4@vger.kernel.org
    Cc: linux-f2fs-devel@lists.sourceforge.net
    Cc: fuse-devel@lists.sourceforge.net
    Cc: cluster-devel@redhat.com
    Cc: linux-mtd@lists.infradead.org
    Cc: jfs-discussion@lists.sourceforge.net
    Cc: linux-nfs@vger.kernel.org
    Cc: linux-nilfs@vger.kernel.org
    Cc: linux-ntfs-dev@lists.sourceforge.net
    Cc: ocfs2-devel@oss.oracle.com
    Cc: reiserfs-devel@vger.kernel.org

    Theodore Ts'o
     

25 Jan, 2014

1 commit

  • * pass on-disk superblock to qnx4_chkroot() explicitly
    * don't leave stale (and unused) pointers in qnx4_super_block
    * free stuff in ->kill_sb(); ->put_super() becomes empty and dies
    * simplify failure exits

    Signed-off-by: Al Viro

    Al Viro
     

09 Nov, 2013

1 commit


29 Jun, 2013

1 commit


04 Mar, 2013

1 commit

  • Modify the request_module to prefix the file system type with "fs-"
    and add aliases to all of the filesystems that can be built as modules
    to match.

    A common practice is to build all of the kernel code and leave code
    that is not commonly needed as modules, with the result that many
    users are exposed to any bug anywhere in the kernel.

    Looking for filesystems with a fs- prefix limits the pool of possible
    modules that can be loaded by mount to just filesystems trivially
    making things safer with no real cost.

    Using aliases means user space can control the policy of which
    filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
    with blacklist and alias directives. Allowing simple, safe,
    well understood work-arounds to known problematic software.

    This also addresses a rare but unfortunate problem where the filesystem
    name is not the same as it's module name and module auto-loading
    would not work. While writing this patch I saw a handful of such
    cases. The most significant being autofs that lives in the module
    autofs4.

    This is relevant to user namespaces because we can reach the request
    module in get_fs_type() without having any special permissions, and
    people get uncomfortable when a user specified string (in this case
    the filesystem type) goes all of the way to request_module.

    After having looked at this issue I don't think there is any
    particular reason to perform any filtering or permission checks beyond
    making it clear in the module request that we want a filesystem
    module. The common pattern in the kernel is to call request_module()
    without regards to the users permissions. In general all a filesystem
    module does once loaded is call register_filesystem() and go to sleep.
    Which means there is not much attack surface exposed by loading a
    filesytem module unless the filesystem is mounted. In a user
    namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
    which most filesystems do not set today.

    Acked-by: Serge Hallyn
    Acked-by: Kees Cook
    Reported-by: Kees Cook
    Signed-off-by: "Eric W. Biederman"

    Eric W. Biederman
     

23 Feb, 2013

1 commit


03 Oct, 2012

2 commits

  • Pull vfs update from Al Viro:

    - big one - consolidation of descriptor-related logics; almost all of
    that is moved to fs/file.c

    (BTW, I'm seriously tempted to rename the result to fd.c. As it is,
    we have a situation when file_table.c is about handling of struct
    file and file.c is about handling of descriptor tables; the reasons
    are historical - file_table.c used to be about a static array of
    struct file we used to have way back).

    A lot of stray ends got cleaned up and converted to saner primitives,
    disgusting mess in android/binder.c is still disgusting, but at least
    doesn't poke so much in descriptor table guts anymore. A bunch of
    relatively minor races got fixed in process, plus an ext4 struct file
    leak.

    - related thing - fget_light() partially unuglified; see fdget() in
    there (and yes, it generates the code as good as we used to have).

    - also related - bits of Cyrill's procfs stuff that got entangled into
    that work; _not_ all of it, just the initial move to fs/proc/fd.c and
    switch of fdinfo to seq_file.

    - Alex's fs/coredump.c spiltoff - the same story, had been easier to
    take that commit than mess with conflicts. The rest is a separate
    pile, this was just a mechanical code movement.

    - a few misc patches all over the place. Not all for this cycle,
    there'll be more (and quite a few currently sit in akpm's tree)."

    Fix up trivial conflicts in the android binder driver, and some fairly
    simple conflicts due to two different changes to the sock_alloc_file()
    interface ("take descriptor handling from sock_alloc_file() to callers"
    vs "net: Providing protocol type via system.sockprotoname xattr of
    /proc/PID/fd entries" adding a dentry name to the socket)

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
    MAX_LFS_FILESIZE should be a loff_t
    compat: fs: Generic compat_sys_sendfile implementation
    fs: push rcu_barrier() from deactivate_locked_super() to filesystems
    btrfs: reada_extent doesn't need kref for refcount
    coredump: move core dump functionality into its own file
    coredump: prevent double-free on an error path in core dumper
    usb/gadget: fix misannotations
    fcntl: fix misannotations
    ceph: don't abuse d_delete() on failure exits
    hypfs: ->d_parent is never NULL or negative
    vfs: delete surplus inode NULL check
    switch simple cases of fget_light to fdget
    new helpers: fdget()/fdput()
    switch o2hb_region_dev_write() to fget_light()
    proc_map_files_readdir(): don't bother with grabbing files
    make get_file() return its argument
    vhost_set_vring(): turn pollstart/pollstop into bool
    switch prctl_set_mm_exe_file() to fget_light()
    switch xfs_find_handle() to fget_light()
    switch xfs_swapext() to fget_light()
    ...

    Linus Torvalds
     
  • There's no reason to call rcu_barrier() on every
    deactivate_locked_super(). We only need to make sure that all delayed rcu
    free inodes are flushed before we destroy related cache.

    Removing rcu_barrier() from deactivate_locked_super() affects some fast
    paths. E.g. on my machine exit_group() of a last process in IPC
    namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time.

    Signed-off-by: Kirill A. Shutemov
    Cc: Al Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Al Viro

    Kirill A. Shutemov
     

21 Sep, 2012

1 commit


31 Jul, 2012

1 commit

  • Use memweight() to count the total number of bits clear in memory area.

    Note that this memweight() call can't be replaced with a single
    bitmap_weight() call, although the pointer to the memory area is aligned
    to long-word boundary. Because the size of the memory area may not be a
    multiple of BITS_PER_LONG, then it returns wrong value on big-endian
    architecture.

    Signed-off-by: Akinobu Mita
    Acked-by: Anders Larsen
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Akinobu Mita
     

14 Jul, 2012

1 commit

  • Just the flags; only NFS cares even about that, but there are
    legitimate uses for such argument. And getting rid of that
    completely would require splitting ->lookup() into a couple
    of methods (at least), so let's leave that alone for now...

    Signed-off-by: Al Viro

    Al Viro
     

21 Mar, 2012

4 commits


20 Jan, 2012

3 commits


09 Jan, 2012

1 commit

  • * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (53 commits)
    Kconfig: acpi: Fix typo in comment.
    misc latin1 to utf8 conversions
    devres: Fix a typo in devm_kfree comment
    btrfs: free-space-cache.c: remove extra semicolon.
    fat: Spelling s/obsolate/obsolete/g
    SCSI, pmcraid: Fix spelling error in a pmcraid_err() call
    tools/power turbostat: update fields in manpage
    mac80211: drop spelling fix
    types.h: fix comment spelling for 'architectures'
    typo fixes: aera -> area, exntension -> extension
    devices.txt: Fix typo of 'VMware'.
    sis900: Fix enum typo 'sis900_rx_bufer_status'
    decompress_bunzip2: remove invalid vi modeline
    treewide: Fix comment and string typo 'bufer'
    hyper-v: Update MAINTAINERS
    treewide: Fix typos in various parts of the kernel, and fix some comments.
    clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR
    gpio: Kconfig: drop unknown symbol 'CS5535_GPIO'
    leds: Kconfig: Fix typo 'D2NET_V2'
    sound: Kconfig: drop unknown symbol ARCH_CLPS7500
    ...

    Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new
    kconfig additions, close to removed commented-out old ones)

    Linus Torvalds
     

04 Jan, 2012

1 commit

  • Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
    it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
    the cost of taking it into inode_init_always() will be negligible for pipes
    and sockets and negative for everything else. Not to mention the removal of
    boilerplate code from ->destroy_inode() instances...

    Signed-off-by: Al Viro

    Al Viro
     

21 Nov, 2011

1 commit


02 Nov, 2011

1 commit


10 Mar, 2011

1 commit

  • Code has been converted over to the new explicit on-stack plugging,
    and delay users have been converted to use the new API for that.
    So lets kill off the old plugging along with aops->sync_page().

    Signed-off-by: Jens Axboe

    Jens Axboe
     

07 Jan, 2011

1 commit

  • RCU free the struct inode. This will allow:

    - Subsequent store-free path walking patch. The inode must be consulted for
    permissions when walking, so an RCU inode reference is a must.
    - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
    to take i_lock no longer need to take sb_inode_list_lock to walk the list in
    the first place. This will simplify and optimize locking.
    - Could remove some nested trylock loops in dcache code
    - Could potentially simplify things a bit in VM land. Do not need to take the
    page lock to follow page->mapping.

    The downsides of this is the performance cost of using RCU. In a simple
    creat/unlink microbenchmark, performance drops by about 10% due to inability to
    reuse cache-hot slab objects. As iterations increase and RCU freeing starts
    kicking over, this increases to about 20%.

    In cases where inode lifetimes are longer (ie. many inodes may be allocated
    during the average life span of a single inode), a lot of this cache reuse is
    not applicable, so the regression caused by this patch is smaller.

    The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
    however this adds some complexity to list walking and store-free path walking,
    so I prefer to implement this at a later date, if it is shown to be a win in
    real situations. I haven't found a regression in any non-micro benchmark so I
    doubt it will be a problem.

    Signed-off-by: Nick Piggin

    Nick Piggin
     

29 Oct, 2010

1 commit


22 Oct, 2010

1 commit

  • All uses of the BKL in qnx4 were the result of a pushdown into
    code that doesn't really need it. As Christoph points out, this
    is a read-only file system, which eliminates most of the races in
    readdir/lookup.

    Signed-off-by: Arnd Bergmann
    Acked-by: Anders Larsen
    Cc: Christoph Hellwig

    Arnd Bergmann
     

05 Oct, 2010

1 commit

  • This patch is a preparation necessary to remove the BKL from do_new_mount().
    It explicitly adds calls to lock_kernel()/unlock_kernel() around
    get_sb/fill_super operations for filesystems that still uses the BKL.

    I've read through all the code formerly covered by the BKL inside
    do_kern_mount() and have satisfied myself that it doesn't need the BKL
    any more.

    do_kern_mount() is already called without the BKL when mounting the rootfs
    and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
    from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
    through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
    afs_mntpt_follow_link(). Both later functions are actually the filesystems
    follow_link inode operation. vfs_kern_mount() is calling the specified
    get_sb function and lets the filesystem do its job by calling the given
    fill_super function.

    Therefore I think it is safe to push down the BKL from the VFS to the
    low-level filesystems get_sb/fill_super operation.

    [arnd: do not add the BKL to those file systems that already
    don't use it elsewhere]

    Signed-off-by: Jan Blunck
    Signed-off-by: Arnd Bergmann
    Cc: Matthew Wilcox
    Cc: Christoph Hellwig

    Jan Blunck
     

10 Aug, 2010

1 commit


28 May, 2010

2 commits

  • We don't name our generic fsync implementations very well currently.
    The no-op implementation for in-memory filesystems currently is called
    simple_sync_file which doesn't make too much sense to start with,
    the the generic one for simple filesystems is called simple_fsync
    which can lead to some confusion.

    This patch renames the generic file fsync method to generic_file_fsync
    to match the other generic_file_* routines it is supposed to be used
    with, and the no-op implementation to noop_fsync to make it obvious
    what to expect. In addition add some documentation for both methods.

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     
  • Do not use the fallback default_llseek() if the readdir operation of the
    filesystem still uses the big kernel lock.

    Since llseek() modifies
    file->f_pos of the directory directly it may need locking to not confuse
    readdir which usually uses file->f_pos directly as well

    Since the special characteristics of the BKL (unlocked on schedule) are
    not necessary in this case, the inode mutex can be used for locking as
    provided by generic_file_llseek(). This is only possible since all
    filesystems, except reiserfs, either use a directory as a flat file or
    with disk address offsets. Reiserfs on the other hand uses a 32bit hash
    off the filename as the offset so generic_file_llseek() can get used as
    well since the hash is always smaller than sb->s_maxbytes (= (512 << 32) -
    blocksize).

    Signed-off-by: Jan Blunck
    Acked-by: Jan Kara
    Acked-by: Anders Larsen
    Cc: Frederic Weisbecker
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    jan Blunck
     

04 Feb, 2010

1 commit

  • As an identical match is wanted in this case, strcmp can be used instead.

    The semantic match that lead to detecting this problem is as follows:
    (http://coccinelle.lip6.fr/)

    //
    @@
    expression foo;
    constant char *abc;
    @@

    *strncmp(foo, abc, sizeof(abc))
    //

    Signed-off-by: Julia Lawall
    Signed-off-by: Anders Larsen
    Signed-off-by: Jiri Kosina

    Julia Lawall
     

16 Dec, 2009

2 commits

  • Use hweight8 instead of counting for each bit

    Signed-off-by: Akinobu Mita
    Acked-by: Anders Larsen
    Cc: Al Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Akinobu Mita
     
  • commit 945ffe54bbd56ceed62de3b908800fd7c6ffb284 ("qnx4: remove write support") removed the (defunct)
    write support but missed a chunk of related, dead code.

    Signed-off-by: Anders Larsen
    Cc: Jiri Kosina
    Acked-by: Christoph Hellwig
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Anders Larsen
     

09 Nov, 2009

1 commit


23 Sep, 2009

1 commit

  • qnx4 wrte support has never been fully implement, is broken since the dawn
    of time and hasn't been actively developed since before git history
    started.

    Instead of letting it further bitrot and complicate API transition (like
    the new truncate code) remove it.

    Signed-off-by: Christoph Hellwig
    Cc: Anders Larsen
    Cc: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Hellwig
     

12 Jun, 2009

1 commit