1. 05 Apr, 2017 1 commit
  2. 24 Mar, 2017 1 commit
  3. 16 Mar, 2017 2 commits
  4. 13 Mar, 2017 1 commit
  5. 10 Mar, 2017 3 commits
    • Andrea Arcangeli's avatar
      userfaultfd: non-cooperative: rollback userfaultfd_exit · dd0db88d
      Andrea Arcangeli authored
      Patch series "userfaultfd non-cooperative further update for 4.11 merge
      window".
      
      Unfortunately I noticed one relevant bug in userfaultfd_exit while doing
      more testing.  I've been doing testing before and this was also tested
      by kbuild bot and exercised by the selftest, but this bug never
      reproduced before.
      
      I dropped userfaultfd_exit as result.  I dropped it because of
      implementation difficulty in receiving signals in __mmput and because I
      think -ENOSPC as result from the background UFFDIO_COPY should be enough
      already.
      
      Before I decided to remove userfaultfd_exit, I noticed userfaultfd_exit
      wasn't exercised by the selftest and when I tried to exercise it, after
      moving it to a more correct place in __mmput where it would make more
      sense and where the vma list is stable, it resulted in the
      event_wait_completion in D state.  So then I added the second patch to
      be sure even if we call userfaultfd_event_wait_completion too late
      during task exit(), we won't risk to generate tasks in D state.  The
      same check exists in handle_userfault() for the same reason, except it
      makes a difference there, while here is just a robustness check and it's
      run under WARN_ON_ONCE.
      
      While looking at the userfaultfd_event_wait_completion() function I
      looked back at its callers too while at it and I think it's not ok to
      stop executing dup_fctx on the fcs list because we relay on
      userfaultfd_event_wait_completion to execute
      userfaultfd_ctx_put(fctx->orig) which is paired against
      userfaultfd_ctx_get(fctx->orig) in dup_userfault just before
      list_add(fcs).  This change only takes care of fctx->orig but this area
      also needs further review looking for similar problems in fctx->new.
      
      The only patch that is urgent is the first because it's an use after
      free during a SMP race condition that affects all processes if
      CONFIG_USERFAULTFD=y.  Very hard to reproduce though and probably
      impossible without SLUB poisoning enabled.
      
      This patch (of 3):
      
      I once reproduced this oops with the userfaultfd selftest, it's not
      easily reproducible and it requires SLUB poisoning to reproduce.
      
          general protection fault: 0000 [#1] SMP
          Modules linked in:
          CPU: 2 PID: 18421 Comm: userfaultfd Tainted: G               ------------ T 3.10.0+ #15
          Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014
          task: ffff8801f83b9440 ti: ffff8801f833c000 task.ti: ffff8801f833c000
          RIP: 0010:[<ffffffff81451299>]  [<ffffffff81451299>] userfaultfd_exit+0x29/0xa0
          RSP: 0018:ffff8801f833fe80  EFLAGS: 00010202
          RAX: ffff8801f833ffd8 RBX: 6b6b6b6b6b6b6b6b RCX: ffff8801f83b9440
          RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8800baf18600
          RBP: ffff8801f833fee8 R08: 0000000000000000 R09: 0000000000000001
          R10: 0000000000000000 R11: ffffffff8127ceb3 R12: 0000000000000000
          R13: ffff8800baf186b0 R14: ffff8801f83b99f8 R15: 00007faed746c700
          FS:  0000000000000000(0000) GS:ffff88023fc80000(0000) knlGS:0000000000000000
          CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
          CR2: 00007faf0966f028 CR3: 0000000001bc6000 CR4: 00000000000006e0
          DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
          DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
          Call Trace:
            do_exit+0x297/0xd10
            SyS_exit+0x17/0x20
            tracesys+0xdd/0xe2
          Code: 00 00 66 66 66 66 90 55 48 89 e5 41 54 53 48 83 ec 58 48 8b 1f 48 85 db 75 11 eb 73 66 0f 1f 44 00 00 48 8b 5b 10 48 85 db 74 64 <4c> 8b a3 b8 00 00 00 4d 85 e4 74 eb 41 f6 84 24 2c 01 00 00 80
          RIP  [<ffffffff81451299>] userfaultfd_exit+0x29/0xa0
           RSP <ffff8801f833fe80>
          ---[ end trace 9fecd6dcb442846a ]---
      
      In the debugger I located the "mm" pointer in the stack and walking
      mm->mmap->vm_next through the end shows the vma->vm_next list is fully
      consistent and it is null terminated list as expected.  So this has to
      be an SMP race condition where userfaultfd_exit was running while the
      vma list was being modified by another CPU.
      
      When userfaultfd_exit() run one of the ->vm_next pointers pointed to
      SLAB_POISON (RBX is the vma pointer and is 0x6b6b..).
      
      The reason is that it's not running in __mmput but while there are still
      other threads running and it's not holding the mmap_sem (it can't as it
      has to wait the even to be received by the manager).  So this is an use
      after free that was happening for all processes.
      
      One more implementation problem aside from the race condition:
      userfaultfd_exit has really to check a flag in mm->flags before walking
      the vma or it's going to slowdown the exit() path for regular tasks.
      
      One more implementation problem: at that point signals can't be
      delivered so it would also create a task in D state if the manager
      doesn't read the event.
      
      The major design issue: it overall looks superfluous as the manager can
      check for -ENOSPC in the background transfer:
      
      	if (mmget_not_zero(ctx->mm)) {
      [..]
      	} else {
      		return -ENOSPC;
      	}
      
      It's safer to roll it back and re-introduce it later if at all.
      
      [rppt@linux.vnet.ibm.com: documentation fixup after removal of UFFD_EVENT_EXIT]
        Link: http://lkml.kernel.org/r/1488345437-4364-1-git-send-email-rppt@linux.vnet.ibm.com
      Link: http://lkml.kernel.org/r/20170224181957.19736-2-aarcange@redhat.comSigned-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
      Acked-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
      Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
      Cc: Mike Kravetz <mike.kravetz@oracle.com>
      Cc: Pavel Emelyanov <xemul@parallels.com>
      Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dd0db88d
    • Masahiro Yamada's avatar
      scripts/spelling.txt: add "overide" pattern and fix typo instances · 505d3085
      Masahiro Yamada authored
      Fix typos and add the following to the scripts/spelling.txt:
      
        overide||override
      
      While we are here, fix the doubled "address" in the touched line
      Documentation/devicetree/bindings/regulator/ti-abb-regulator.txt.
      
      Also, fix the comment block style in the touched hunks in
      drivers/media/dvb-frontends/drx39xyj/drx_driver.h.
      
      Link: http://lkml.kernel.org/r/1481573103-11329-21-git-send-email-yamada.masahiro@socionext.comSigned-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      505d3085
    • Masahiro Yamada's avatar
      scripts/spelling.txt: add "disble(d)" pattern and fix typo instances · 8a1115ff
      Masahiro Yamada authored
      Fix typos and add the following to the scripts/spelling.txt:
      
        disble||disable
        disbled||disabled
      
      I kept the TSL2563_INT_DISBLED in /drivers/iio/light/tsl2563.c
      untouched.  The macro is not referenced at all, but this commit is
      touching only comment blocks just in case.
      
      Link: http://lkml.kernel.org/r/1481573103-11329-20-git-send-email-yamada.masahiro@socionext.comSigned-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8a1115ff
  6. 09 Mar, 2017 4 commits
  7. 07 Mar, 2017 2 commits
  8. 06 Mar, 2017 1 commit
  9. 05 Mar, 2017 1 commit
    • Len Brown's avatar
      cpufreq: Add the "cpufreq.off=1" cmdline option · d82f2692
      Len Brown authored
      Add the "cpufreq.off=1" cmdline option.
      
      At boot-time, this allows a user to request CONFIG_CPU_FREQ=n
      behavior from a kernel built with CONFIG_CPU_FREQ=y.
      
      This is analogous to the existing "cpuidle.off=1" option
      and CONFIG_CPU_IDLE=y
      
      This capability is valuable when we need to debug end-user
      issues in the BIOS or in Linux.  It is also convenient
      for enabling comparisons, which may otherwise require a new kernel,
      or help from BIOS SETUP, which may be buggy or unavailable.
      Signed-off-by: default avatarLen Brown <len.brown@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      d82f2692
  10. 03 Mar, 2017 7 commits
    • John Keeping's avatar
      Documentation/sphinx: fix primary_domain configuration · fd5d6669
      John Keeping authored
      With Sphinx 1.5.3 I get the warning:
      
      	WARNING: primary_domain 'C' not found, ignored.
      
      It seems that domain names in Sphinx are case-sensitive and for the C
      domain the name must be lower case.
      Signed-off-by: default avatarJohn Keeping <john@metanate.com>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      fd5d6669
    • Martyn Welch's avatar
      docs: Fix htmldocs build failure · f3fc83e5
      Martyn Welch authored
      Build of HTML docs failing due to conversion of deviceiobook.tmpl in
      8a8a602f and regulator.tmpl in 028f2533 to RST without removing from
      DOCBOOKS in Makefile, resulting (in the case of deviceiobook) the
      following error:
      
      make[1]: *** No rule to make target 'Documentation/DocBook/deviceiobook.xml', needed by 'Documentation/DocBook/deviceiobook.aux.xml'.  Stop.
      Makefile:1452: recipe for target 'htmldocs' failed
      make: *** [htmldocs] Error 2
      
      Update DOCBOOKS to reflect available books.
      Signed-off-by: default avatarMartyn Welch <martyn.welch@collabora.co.uk>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      f3fc83e5
    • SeongJae Park's avatar
      doc/ko_KR/memory-barriers: Update control-dependencies section · 9857b1ad
      SeongJae Park authored
      This commit applies upstream change, commit c8241f85 ("doc: Update
      control-dependencies section of memory-barriers.txt"), to Korean
      translation.
      Signed-off-by: default avatarSeongJae Park <sj38.park@gmail.com>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      9857b1ad
    • Cao jin's avatar
      pcieaer doc: update the link · 2eb6a4b2
      Cao jin authored
      The original link is empty, replace it.
      Signed-off-by: default avatarCao jin <caoj.fnst@cn.fujitsu.com>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      2eb6a4b2
    • Krzysztof Kozlowski's avatar
      Documentation: Update path to sysrq.txt · d3c1a297
      Krzysztof Kozlowski authored
      Commit 9d85025b ("docs-rst: create an user's manual book") moved the
      sysrq.txt leaving old paths in the kernel docs.
      Signed-off-by: default avatarKrzysztof Kozlowski <krzk@kernel.org>
      Reviewed-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      d3c1a297
    • Todd Brandt's avatar
      ftrace/graph: Add ftrace_graph_max_depth kernel parameter · 65a50c65
      Todd Brandt authored
      Early trace callgraphs can be extremely large on systems with
      several seconds of boot time. The max_depth parameter limits how
      deep the graph trace goes and reduces the output size. This
      parameter is the same as the max_graph_depth file in tracefs.
      
      Link: http://lkml.kernel.org/r/1488499935-23216-1-git-send-email-todd.e.brandt@linux.intel.comSigned-off-by: default avatarTodd Brandt <todd.e.brandt@linux.intel.com>
      [ changed comments about debugfs to tracefs ]
      Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      65a50c65
    • David Howells's avatar
      statx: Add a system call to make enhanced file info available · a528d35e
      David Howells authored
      Add a system call to make extended file information available, including
      file creation and some attribute flags where available through the
      underlying filesystem.
      
      The getattr inode operation is altered to take two additional arguments: a
      u32 request_mask and an unsigned int flags that indicate the
      synchronisation mode.  This change is propagated to the vfs_getattr*()
      function.
      
      Functions like vfs_stat() are now inline wrappers around new functions
      vfs_statx() and vfs_statx_fd() to reduce stack usage.
      
      ========
      OVERVIEW
      ========
      
      The idea was initially proposed as a set of xattrs that could be retrieved
      with getxattr(), but the general preference proved to be for a new syscall
      with an extended stat structure.
      
      A number of requests were gathered for features to be included.  The
      following have been included:
      
       (1) Make the fields a consistent size on all arches and make them large.
      
       (2) Spare space, request flags and information flags are provided for
           future expansion.
      
       (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
           __s64).
      
       (4) Creation time: The SMB protocol carries the creation time, which could
           be exported by Samba, which will in turn help CIFS make use of
           FS-Cache as that can be used for coherency data (stx_btime).
      
           This is also specified in NFSv4 as a recommended attribute and could
           be exported by NFSD [Steve French].
      
       (5) Lightweight stat: Ask for just those details of interest, and allow a
           netfs (such as NFS) to approximate anything not of interest, possibly
           without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
           Dilger] (AT_STATX_DONT_SYNC).
      
       (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
           its cached attributes are up to date [Trond Myklebust]
           (AT_STATX_FORCE_SYNC).
      
      And the following have been left out for future extension:
      
       (7) Data version number: Could be used by userspace NFS servers [Aneesh
           Kumar].
      
           Can also be used to modify fill_post_wcc() in NFSD which retrieves
           i_version directly, but has just called vfs_getattr().  It could get
           it from the kstat struct if it used vfs_xgetattr() instead.
      
           (There's disagreement on the exact semantics of a single field, since
           not all filesystems do this the same way).
      
       (8) BSD stat compatibility: Including more fields from the BSD stat such
           as creation time (st_btime) and inode generation number (st_gen)
           [Jeremy Allison, Bernd Schubert].
      
       (9) Inode generation number: Useful for FUSE and userspace NFS servers
           [Bernd Schubert].
      
           (This was asked for but later deemed unnecessary with the
           open-by-handle capability available and caused disagreement as to
           whether it's a security hole or not).
      
      (10) Extra coherency data may be useful in making backups [Andreas Dilger].
      
           (No particular data were offered, but things like last backup
           timestamp, the data version number and the DOS archive bit would come
           into this category).
      
      (11) Allow the filesystem to indicate what it can/cannot provide: A
           filesystem can now say it doesn't support a standard stat feature if
           that isn't available, so if, for instance, inode numbers or UIDs don't
           exist or are fabricated locally...
      
           (This requires a separate system call - I have an fsinfo() call idea
           for this).
      
      (12) Store a 16-byte volume ID in the superblock that can be returned in
           struct xstat [Steve French].
      
           (Deferred to fsinfo).
      
      (13) Include granularity fields in the time data to indicate the
           granularity of each of the times (NFSv4 time_delta) [Steve French].
      
           (Deferred to fsinfo).
      
      (14) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
           Note that the Linux IOC flags are a mess and filesystems such as Ext4
           define flags that aren't in linux/fs.h, so translation in the kernel
           may be a necessity (or, possibly, we provide the filesystem type too).
      
           (Some attributes are made available in stx_attributes, but the general
           feeling was that the IOC flags were to ext[234]-specific and shouldn't
           be exposed through statx this way).
      
      (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
           Michael Kerrisk].
      
           (Deferred, probably to fsinfo.  Finding out if there's an ACL or
           seclabal might require extra filesystem operations).
      
      (16) Femtosecond-resolution timestamps [Dave Chinner].
      
           (A __reserved field has been left in the statx_timestamp struct for
           this - if there proves to be a need).
      
      (17) A set multiple attributes syscall to go with this.
      
      ===============
      NEW SYSTEM CALL
      ===============
      
      The new system call is:
      
      	int ret = statx(int dfd,
      			const char *filename,
      			unsigned int flags,
      			unsigned int mask,
      			struct statx *buffer);
      
      The dfd, filename and flags parameters indicate the file to query, in a
      similar way to fstatat().  There is no equivalent of lstat() as that can be
      emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags.  There is
      also no equivalent of fstat() as that can be emulated by passing a NULL
      filename to statx() with the fd of interest in dfd.
      
      Whether or not statx() synchronises the attributes with the backing store
      can be controlled by OR'ing a value into the flags argument (this typically
      only affects network filesystems):
      
       (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
           respect.
      
       (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
           its attributes with the server - which might require data writeback to
           occur to get the timestamps correct.
      
       (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
           network filesystem.  The resulting values should be considered
           approximate.
      
      mask is a bitmask indicating the fields in struct statx that are of
      interest to the caller.  The user should set this to STATX_BASIC_STATS to
      get the basic set returned by stat().  It should be noted that asking for
      more information may entail extra I/O operations.
      
      buffer points to the destination for the data.  This must be 256 bytes in
      size.
      
      ======================
      MAIN ATTRIBUTES RECORD
      ======================
      
      The following structures are defined in which to return the main attribute
      set:
      
      	struct statx_timestamp {
      		__s64	tv_sec;
      		__s32	tv_nsec;
      		__s32	__reserved;
      	};
      
      	struct statx {
      		__u32	stx_mask;
      		__u32	stx_blksize;
      		__u64	stx_attributes;
      		__u32	stx_nlink;
      		__u32	stx_uid;
      		__u32	stx_gid;
      		__u16	stx_mode;
      		__u16	__spare0[1];
      		__u64	stx_ino;
      		__u64	stx_size;
      		__u64	stx_blocks;
      		__u64	__spare1[1];
      		struct statx_timestamp	stx_atime;
      		struct statx_timestamp	stx_btime;
      		struct statx_timestamp	stx_ctime;
      		struct statx_timestamp	stx_mtime;
      		__u32	stx_rdev_major;
      		__u32	stx_rdev_minor;
      		__u32	stx_dev_major;
      		__u32	stx_dev_minor;
      		__u64	__spare2[14];
      	};
      
      The defined bits in request_mask and stx_mask are:
      
      	STATX_TYPE		Want/got stx_mode & S_IFMT
      	STATX_MODE		Want/got stx_mode & ~S_IFMT
      	STATX_NLINK		Want/got stx_nlink
      	STATX_UID		Want/got stx_uid
      	STATX_GID		Want/got stx_gid
      	STATX_ATIME		Want/got stx_atime{,_ns}
      	STATX_MTIME		Want/got stx_mtime{,_ns}
      	STATX_CTIME		Want/got stx_ctime{,_ns}
      	STATX_INO		Want/got stx_ino
      	STATX_SIZE		Want/got stx_size
      	STATX_BLOCKS		Want/got stx_blocks
      	STATX_BASIC_STATS	[The stuff in the normal stat struct]
      	STATX_BTIME		Want/got stx_btime{,_ns}
      	STATX_ALL		[All currently available stuff]
      
      stx_btime is the file creation time, stx_mask is a bitmask indicating the
      data provided and __spares*[] are where as-yet undefined fields can be
      placed.
      
      Time fields are structures with separate seconds and nanoseconds fields
      plus a reserved field in case we want to add even finer resolution.  Note
      that times will be negative if before 1970; in such a case, the nanosecond
      fields will also be negative if not zero.
      
      The bits defined in the stx_attributes field convey information about a
      file, how it is accessed, where it is and what it does.  The following
      attributes map to FS_*_FL flags and are the same numerical value:
      
      	STATX_ATTR_COMPRESSED		File is compressed by the fs
      	STATX_ATTR_IMMUTABLE		File is marked immutable
      	STATX_ATTR_APPEND		File is append-only
      	STATX_ATTR_NODUMP		File is not to be dumped
      	STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs
      
      Within the kernel, the supported flags are listed by:
      
      	KSTAT_ATTR_FS_IOC_FLAGS
      
      [Are any other IOC flags of sufficient general interest to be exposed
      through this interface?]
      
      New flags include:
      
      	STATX_ATTR_AUTOMOUNT		Object is an automount trigger
      
      These are for the use of GUI tools that might want to mark files specially,
      depending on what they are.
      
      Fields in struct statx come in a number of classes:
      
       (0) stx_dev_*, stx_blksize.
      
           These are local system information and are always available.
      
       (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
           stx_size, stx_blocks.
      
           These will be returned whether the caller asks for them or not.  The
           corresponding bits in stx_mask will be set to indicate whether they
           actually have valid values.
      
           If the caller didn't ask for them, then they may be approximated.  For
           example, NFS won't waste any time updating them from the server,
           unless as a byproduct of updating something requested.
      
           If the values don't actually exist for the underlying object (such as
           UID or GID on a DOS file), then the bit won't be set in the stx_mask,
           even if the caller asked for the value.  In such a case, the returned
           value will be a fabrication.
      
           Note that there are instances where the type might not be valid, for
           instance Windows reparse points.
      
       (2) stx_rdev_*.
      
           This will be set only if stx_mode indicates we're looking at a
           blockdev or a chardev, otherwise will be 0.
      
       (3) stx_btime.
      
           Similar to (1), except this will be set to 0 if it doesn't exist.
      
      =======
      TESTING
      =======
      
      The following test program can be used to test the statx system call:
      
      	samples/statx/test-statx.c
      
      Just compile and run, passing it paths to the files you want to examine.
      The file is built automatically if CONFIG_SAMPLES is enabled.
      
      Here's some example output.  Firstly, an NFS directory that crosses to
      another FSID.  Note that the AUTOMOUNT attribute is set because transiting
      this directory will cause d_automount to be invoked by the VFS.
      
      	[root@andromeda ~]# /tmp/test-statx -A /warthog/data
      	statx(/warthog/data) = 0
      	results=7ff
      	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
      	Device: 00:26           Inode: 1703937     Links: 125
      	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
      	Access: 2016-11-24 09:02:12.219699527+0000
      	Modify: 2016-11-17 10:44:36.225653653+0000
      	Change: 2016-11-17 10:44:36.225653653+0000
      	Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)
      
      Secondly, the result of automounting on that directory.
      
      	[root@andromeda ~]# /tmp/test-statx /warthog/data
      	statx(/warthog/data) = 0
      	results=7ff
      	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
      	Device: 00:27           Inode: 2           Links: 125
      	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
      	Access: 2016-11-24 09:02:12.219699527+0000
      	Modify: 2016-11-17 10:44:36.225653653+0000
      	Change: 2016-11-17 10:44:36.225653653+0000
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      a528d35e
  11. 01 Mar, 2017 3 commits
    • David Howells's avatar
      KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload() · 0837e49a
      David Howells authored
      rcu_dereference_key() and user_key_payload() are currently being used in
      two different, incompatible ways:
      
       (1) As a wrapper to rcu_dereference() - when only the RCU read lock used
           to protect the key.
      
       (2) As a wrapper to rcu_dereference_protected() - when the key semaphor is
           used to protect the key and the may be being modified.
      
      Fix this by splitting both of the key wrappers to produce:
      
       (1) RCU accessors for keys when caller has the key semaphore locked:
      
      	dereference_key_locked()
      	user_key_payload_locked()
      
       (2) RCU accessors for keys when caller holds the RCU read lock:
      
      	dereference_key_rcu()
      	user_key_payload_rcu()
      
      This should fix following warning in the NFS idmapper
      
        ===============================
        [ INFO: suspicious RCU usage. ]
        4.10.0 #1 Tainted: G        W
        -------------------------------
        ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage!
        other info that might help us debug this:
        rcu_scheduler_active = 2, debug_locks = 0
        1 lock held by mount.nfs/5987:
          #0:  (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4]
        stack backtrace:
        CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G        W       4.10.0 #1
        Call Trace:
          dump_stack+0xe8/0x154 (unreliable)
          lockdep_rcu_suspicious+0x140/0x190
          nfs_idmap_get_key+0x380/0x420 [nfsv4]
          nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4]
          decode_getfattr_attrs+0xfac/0x16b0 [nfsv4]
          decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4]
          nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4]
          rpcauth_unwrap_resp+0xe8/0x140 [sunrpc]
          call_decode+0x29c/0x910 [sunrpc]
          __rpc_execute+0x140/0x8f0 [sunrpc]
          rpc_run_task+0x170/0x200 [sunrpc]
          nfs4_call_sync_sequence+0x68/0xa0 [nfsv4]
          _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4]
          nfs4_lookup_root+0xe0/0x350 [nfsv4]
          nfs4_lookup_root_sec+0x70/0xa0 [nfsv4]
          nfs4_find_root_sec+0xc4/0x100 [nfsv4]
          nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4]
          nfs4_get_rootfh+0x6c/0x190 [nfsv4]
          nfs4_server_common_setup+0xc4/0x260 [nfsv4]
          nfs4_create_server+0x278/0x3c0 [nfsv4]
          nfs4_remote_mount+0x50/0xb0 [nfsv4]
          mount_fs+0x74/0x210
          vfs_kern_mount+0x78/0x220
          nfs_do_root_mount+0xb0/0x140 [nfsv4]
          nfs4_try_mount+0x60/0x100 [nfsv4]
          nfs_fs_mount+0x5ec/0xda0 [nfs]
          mount_fs+0x74/0x210
          vfs_kern_mount+0x78/0x220
          do_mount+0x254/0xf70
          SyS_mount+0x94/0x100
          system_call+0x38/0xe0
      Reported-by: default avatarJan Stancek <jstancek@redhat.com>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Tested-by: default avatarJan Stancek <jstancek@redhat.com>
      Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
      0837e49a
    • Viresh Kumar's avatar
      PM / OPP: Documentation: Fix opp-microvolt in examples · 28db0c7b
      Viresh Kumar authored
      The triplet present in "opp-microvolt" property should be in the order
      <target min max>, while all the examples have it in the order
      <min target max>.
      
      Fix it.
      
      Luckily all of the users of "opp-microvolt" property have applied brain
      instead of copying the examples from documentation and none of the
      actual dts files have it wrong.
      Reported-by: default avatarRob Herring <robh@kernel.org>
      Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      28db0c7b
    • Anton Blanchard's avatar
      perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS · 6b0b7551
      Anton Blanchard authored
      We have uses of CONFIG_UPROBE_EVENT and CONFIG_KPROBE_EVENT as
      well as CONFIG_UPROBE_EVENTS and CONFIG_KPROBE_EVENTS.
      
      Consistently use the plurals.
      Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: acme@kernel.org
      Cc: alexander.shishkin@linux.intel.com
      Cc: davem@davemloft.net
      Cc: sparclinux@vger.kernel.org
      Link: http://lkml.kernel.org/r/20170216060050.20866-1-anton@ozlabs.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      6b0b7551
  12. 28 Feb, 2017 10 commits
  13. 25 Feb, 2017 4 commits