Commit Graph

746 Commits

Author SHA1 Message Date
Andrew Morton a61fc2cbdf ipc/shm.c: shm_split(): remove unneeded test for NULL shm_file_data.vm_ops
This was added by the recent "ipc/shm.c: add split function to
shm_vm_ops", but it is not necessary.

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:38 -07:00
Davidlohr Bueso 23c8cec8cf ipc/msg: introduce msgctl(MSG_STAT_ANY)
There is a permission discrepancy when consulting msq ipc object
metadata between /proc/sysvipc/msg (0444) and the MSG_STAT shmctl
command.  The later does permission checks for the object vs S_IRUGO.
As such there can be cases where EACCESS is returned via syscall but the
info is displayed anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the msq metadata), this behavior goes way back and showing
all the objects regardless of the permissions was most likely an
overlook - so we are stuck with it.  Furthermore, modifying either the
syscall or the procfs file can cause userspace programs to break (ie
ipcs).  Some applications require getting the procfs info (without root
privileges) and can be rather slow in comparison with a syscall -- up to
500x in some reported cases for shm.

This patch introduces a new MSG_STAT_ANY command such that the msq ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

Link: http://lkml.kernel.org/r/20180215162458.10059-4-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Robert Kettler <robert.kettler@outlook.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:37 -07:00
Davidlohr Bueso a280d6dc77 ipc/sem: introduce semctl(SEM_STAT_ANY)
There is a permission discrepancy when consulting shm ipc object
metadata between /proc/sysvipc/sem (0444) and the SEM_STAT semctl
command.  The later does permission checks for the object vs S_IRUGO.
As such there can be cases where EACCESS is returned via syscall but the
info is displayed anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the sma metadata), this behavior goes way back and showing
all the objects regardless of the permissions was most likely an
overlook - so we are stuck with it.  Furthermore, modifying either the
syscall or the procfs file can cause userspace programs to break (ie
ipcs).  Some applications require getting the procfs info (without root
privileges) and can be rather slow in comparison with a syscall -- up to
500x in some reported cases for shm.

This patch introduces a new SEM_STAT_ANY command such that the sem ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

Link: http://lkml.kernel.org/r/20180215162458.10059-3-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Robert Kettler <robert.kettler@outlook.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:37 -07:00
Davidlohr Bueso c21a6970ae ipc/shm: introduce shmctl(SHM_STAT_ANY)
Patch series "sysvipc: introduce STAT_ANY commands", v2.

The following patches adds the discussed (see [1]) new command for shm
as well as for sems and msq as they are subject to the same
discrepancies for ipc object permission checks between the syscall and
via procfs.  These new commands are justified in that (1) we are stuck
with this semantics as changing syscall and procfs can break userland;
and (2) some users can benefit from performance (for large amounts of
shm segments, for example) from not having to parse the procfs
interface.

Once merged, I will submit the necesary manpage updates.  But I'm thinking
something like:

: diff --git a/man2/shmctl.2 b/man2/shmctl.2
: index 7bb503999941..bb00bbe21a57 100644
: --- a/man2/shmctl.2
: +++ b/man2/shmctl.2
: @@ -41,6 +41,7 @@
:  .\" 2005-04-25, mtk -- noted aberrant Linux behavior w.r.t. new
:  .\"	attaches to a segment that has already been marked for deletion.
:  .\" 2005-08-02, mtk: Added IPC_INFO, SHM_INFO, SHM_STAT descriptions.
: +.\" 2018-02-13, dbueso: Added SHM_STAT_ANY description.
:  .\"
:  .TH SHMCTL 2 2017-09-15 "Linux" "Linux Programmer's Manual"
:  .SH NAME
: @@ -242,6 +243,18 @@ However, the
:  argument is not a segment identifier, but instead an index into
:  the kernel's internal array that maintains information about
:  all shared memory segments on the system.
: +.TP
: +.BR SHM_STAT_ANY " (Linux-specific)"
: +Return a
: +.I shmid_ds
: +structure as for
: +.BR SHM_STAT .
: +However, the
: +.I shm_perm.mode
: +is not checked for read access for
: +.IR shmid ,
: +resembing the behaviour of
: +/proc/sysvipc/shm.
:  .PP
:  The caller can prevent or allow swapping of a shared
:  memory segment with the following \fIcmd\fP values:
: @@ -287,7 +300,7 @@ operation returns the index of the highest used entry in the
:  kernel's internal array recording information about all
:  shared memory segments.
:  (This information can be used with repeated
: -.B SHM_STAT
: +.B SHM_STAT/SHM_STAT_ANY
:  operations to obtain information about all shared memory segments
:  on the system.)
:  A successful
: @@ -328,7 +341,7 @@ isn't accessible.
:  \fIshmid\fP is not a valid identifier, or \fIcmd\fP
:  is not a valid command.
:  Or: for a
: -.B SHM_STAT
: +.B SHM_STAT/SHM_STAT_ANY
:  operation, the index value specified in
:  .I shmid
:  referred to an array slot that is currently unused.

This patch (of 3):

There is a permission discrepancy when consulting shm ipc object metadata
between /proc/sysvipc/shm (0444) and the SHM_STAT shmctl command.  The
later does permission checks for the object vs S_IRUGO.  As such there can
be cases where EACCESS is returned via syscall but the info is displayed
anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the shm metadata), this behavior goes way back and showing all
the objects regardless of the permissions was most likely an overlook - so
we are stuck with it.  Furthermore, modifying either the syscall or the
procfs file can cause userspace programs to break (ie ipcs).  Some
applications require getting the procfs info (without root privileges) and
can be rather slow in comparison with a syscall -- up to 500x in some
reported cases.

This patch introduces a new SHM_STAT_ANY command such that the shm ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

[1] https://lkml.org/lkml/2017/12/19/220

Link: http://lkml.kernel.org/r/20180215162458.10059-2-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Robert Kettler <robert.kettler@outlook.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:37 -07:00
Alexey Dobriyan e74a0effff proc: move /proc/sysvipc creation to where it belongs
Move the proc_mkdir() call within the sysvipc subsystem such that we
avoid polluting proc_root_init() with petty cpp.

[dave@stgolabs.net: contributed changelog]
Link: http://lkml.kernel.org/r/20180216161732.GA10297@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:33 -07:00
Linus Torvalds 17dec0a949 Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman:
 "There was a lot of work this cycle fixing bugs that were discovered
  after the merge window and getting everything ready where we can
  reasonably support fully unprivileged fuse. The bug fixes you already
  have and much of the unprivileged fuse work is coming in via other
  trees.

  Still left for fully unprivileged fuse is figuring out how to cleanly
  handle .set_acl and .get_acl in the legacy case, and properly handling
  of evm xattrs on unprivileged mounts.

  Included in the tree is a cleanup from Alexely that replaced a linked
  list with a statically allocated fix sized array for the pid caches,
  which simplifies and speeds things up.

  Then there is are some cleanups and fixes for the ipc namespace. The
  motivation was that in reviewing other code it was discovered that
  access ipc objects from different pid namespaces recorded pids in such
  a way that when asked the wrong pids were returned. In the worst case
  there has been a measured 30% performance impact for sysvipc
  semaphores. Other test cases showed no measurable performance impact.
  Manfred Spraul and Davidlohr Bueso who tend to work on sysvipc
  performance both gave the nod that this is good enough.

  Casey Schaufler and James Morris have given their approval to the LSM
  side of the changes.

  I simplified the types and the code dealing with sysvipc to pass just
  kern_ipc_perm for all three types of ipc. Which reduced the header
  dependencies throughout the kernel and simplified the lsm code.

  Which let me work on the pid fixes without having to worry about
  trivial changes causing complete kernel recompiles"

* 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  ipc/shm: Fix pid freeing.
  ipc/shm: fix up for struct file no longer being available in shm.h
  ipc/smack: Tidy up from the change in type of the ipc security hooks
  ipc: Directly call the security hook in ipc_ops.associate
  ipc/sem: Fix semctl(..., GETPID, ...) between pid namespaces
  ipc/msg: Fix msgctl(..., IPC_STAT, ...) between pid namespaces
  ipc/shm: Fix shmctl(..., IPC_STAT, ...) between pid namespaces.
  ipc/util: Helpers for making the sysvipc operations pid namespace aware
  ipc: Move IPCMNI from include/ipc.h into ipc/util.h
  msg: Move struct msg_queue into ipc/msg.c
  shm: Move struct shmid_kernel into ipc/shm.c
  sem: Move struct sem and struct sem_array into ipc/sem.c
  msg/security: Pass kern_ipc_perm not msg_queue into the msg_queue security hooks
  shm/security: Pass kern_ipc_perm not shmid_kernel into the shm security hooks
  sem/security: Pass kern_ipc_perm not sem_array into the sem security hooks
  pidns: simpler allocation of pid_* caches
2018-04-03 19:15:32 -07:00
Linus Torvalds 642e7fd233 Merge branch 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux
Pull removal of in-kernel calls to syscalls from Dominik Brodowski:
 "System calls are interaction points between userspace and the kernel.
  Therefore, system call functions such as sys_xyzzy() or
  compat_sys_xyzzy() should only be called from userspace via the
  syscall table, but not from elsewhere in the kernel.

  At least on 64-bit x86, it will likely be a hard requirement from
  v4.17 onwards to not call system call functions in the kernel: It is
  better to use use a different calling convention for system calls
  there, where struct pt_regs is decoded on-the-fly in a syscall wrapper
  which then hands processing over to the actual syscall function. This
  means that only those parameters which are actually needed for a
  specific syscall are passed on during syscall entry, instead of
  filling in six CPU registers with random user space content all the
  time (which may cause serious trouble down the call chain). Those
  x86-specific patches will be pushed through the x86 tree in the near
  future.

  Moreover, rules on how data may be accessed may differ between kernel
  data and user data. This is another reason why calling sys_xyzzy() is
  generally a bad idea, and -- at most -- acceptable in arch-specific
  code.

  This patchset removes all in-kernel calls to syscall functions in the
  kernel with the exception of arch/. On top of this, it cleans up the
  three places where many syscalls are referenced or prototyped, namely
  kernel/sys_ni.c, include/linux/syscalls.h and include/linux/compat.h"

* 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux: (109 commits)
  bpf: whitelist all syscalls for error injection
  kernel/sys_ni: remove {sys_,sys_compat} from cond_syscall definitions
  kernel/sys_ni: sort cond_syscall() entries
  syscalls/x86: auto-create compat_sys_*() prototypes
  syscalls: sort syscall prototypes in include/linux/compat.h
  net: remove compat_sys_*() prototypes from net/compat.h
  syscalls: sort syscall prototypes in include/linux/syscalls.h
  kexec: move sys_kexec_load() prototype to syscalls.h
  x86/sigreturn: use SYSCALL_DEFINE0
  x86: fix sys_sigreturn() return type to be long, not unsigned long
  x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm()
  mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead()
  mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff()
  mm: add ksys_fadvise64_64() helper; remove in-kernel call to sys_fadvise64_64()
  fs: add ksys_fallocate() wrapper; remove in-kernel calls to sys_fallocate()
  fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscalls
  fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate()
  fs: add ksys_sync_file_range helper(); remove in-kernel calls to syscall
  kernel: add ksys_setsid() helper; remove in-kernel call to sys_setsid()
  kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare()
  ...
2018-04-02 21:22:12 -07:00
Dominik Brodowski 31c213f210 ipc: add msgsnd syscall/compat_syscall wrappers
Provide ksys_msgsnd() and compat_ksys_msgsnd() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_msgsnd() and compat_sys_msgsnd().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:28 +02:00
Dominik Brodowski 078faac9e8 ipc: add msgrcv syscall/compat_syscall wrappers
Provide ksys_msgrcv() and compat_ksys_msgrcv() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_msgrcv() and compat_sys_msgrcv().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:27 +02:00
Dominik Brodowski e340db5648 ipc: add msgctl syscall/compat_syscall wrappers
Provide ksys_msgctl() and compat_ksys_msgctl() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_msgctl() and compat_sys_msgctl().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:26 +02:00
Dominik Brodowski c84d0791df ipc: add shmctl syscall/compat_syscall wrappers
Provide ksys_shmctl() and compat_ksys_shmctl() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_shmctl() and compat_sys_shmctl().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:25 +02:00
Dominik Brodowski da1e274434 ipc: add shmdt syscall wrapper
Provide ksys_shmdt() wrapper to avoid in-kernel calls to this syscall.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_shmdt().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:25 +02:00
Dominik Brodowski 65749e0bb5 ipc: add shmget syscall wrapper
Provide ksys_shmget() wrapper to avoid in-kernel calls to this syscall.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_shmget().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:24 +02:00
Dominik Brodowski 3d65661a49 ipc: add msgget syscall wrapper
Provide ksys_msgget() wrapper to avoid in-kernel calls to this syscall.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_msgget().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:23 +02:00
Dominik Brodowski d969c6fa72 ipc: add semctl syscall/compat_syscall wrappers
Provide ksys_semctl() and compat_ksys_semctl() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_semctl() and compat_sys_semctl().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:22 +02:00
Dominik Brodowski 69894718a5 ipc: add semget syscall wrapper
Provide ksys_semget() wrapper to avoid in-kernel calls to this syscall.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_semget().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:22 +02:00
Dominik Brodowski 41f4f0e2f5 ipc: add semtimedop syscall/compat_syscall wrappers
Provide ksys_semtimedop() and compat_ksys_semtimedop() wrappers to avoid
in-kernel calls to these syscalls. The ksys_ prefix denotes that these
functions are meant as a drop-in replacement for the syscalls. In
particular, they use the same calling convention as sys_semtimedop() and
compat_sys_semtimedop().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:21 +02:00
Mike Kravetz 3d942ee079 ipc/shm.c: add split function to shm_vm_ops
If System V shmget/shmat operations are used to create a hugetlbfs
backed mapping, it is possible to munmap part of the mapping and split
the underlying vma such that it is not huge page aligned.  This will
untimately result in the following BUG:

  kernel BUG at /build/linux-jWa1Fv/linux-4.15.0/mm/hugetlb.c:3310!
  Oops: Exception in kernel mode, sig: 5 [#1]
  LE SMP NR_CPUS=2048 NUMA PowerNV
  Modules linked in: kcm nfc af_alg caif_socket caif phonet fcrypt
  CPU: 18 PID: 43243 Comm: trinity-subchil Tainted: G         C  E 4.15.0-10-generic #11-Ubuntu
  NIP:  c00000000036e764 LR: c00000000036ee48 CTR: 0000000000000009
  REGS: c000003fbcdcf810 TRAP: 0700   Tainted: G         C  E (4.15.0-10-generic)
  MSR:  9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 24002222  XER: 20040000
  CFAR: c00000000036ee44 SOFTE: 1
  NIP __unmap_hugepage_range+0xa4/0x760
  LR __unmap_hugepage_range_final+0x28/0x50
  Call Trace:
    0x7115e4e00000 (unreliable)
    __unmap_hugepage_range_final+0x28/0x50
    unmap_single_vma+0x11c/0x190
    unmap_vmas+0x94/0x140
    exit_mmap+0x9c/0x1d0
    mmput+0xa8/0x1d0
    do_exit+0x360/0xc80
    do_group_exit+0x60/0x100
    SyS_exit_group+0x24/0x30
    system_call+0x58/0x6c
  ---[ end trace ee88f958a1c62605 ]---

This bug was introduced by commit 31383c6865 ("mm, hugetlbfs:
introduce ->split() to vm_operations_struct").  A split function was
added to vm_operations_struct to determine if a mapping can be split.
This was mostly for device-dax and hugetlbfs mappings which have
specific alignment constraints.

Mappings initiated via shmget/shmat have their original vm_ops
overwritten with shm_vm_ops.  shm_vm_ops functions will call back to the
original vm_ops if needed.  Add such a split function to shm_vm_ops.

Link: http://lkml.kernel.org/r/20180321161314.7711-1-mike.kravetz@oracle.com
Fixes: 31383c6865 ("mm, hugetlbfs: introduce ->split() to vm_operations_struct")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-28 13:42:05 -10:00
Eric W. Biederman 2236d4d390 ipc/shm: Fix pid freeing.
The 0day kernel test build report reported an oops:
>
>  IP: put_pid+0x22/0x5c
>  PGD 19efa067 P4D 19efa067 PUD 0
>  Oops: 0000 [#1]
>  CPU: 0 PID: 727 Comm: trinity Not tainted 4.16.0-rc2-00010-g98f929b #1
>  RIP: 0010:put_pid+0x22/0x5c
>  RSP: 0018:ffff986719f73e48 EFLAGS: 00010202
>  RAX: 00000006d765f710 RBX: ffff98671a4fa4d0 RCX: ffff986719f73d40
>  RDX: 000000006f6e6125 RSI: 0000000000000000 RDI: ffffffffa01e6d21
>  RBP: ffffffffa0955fe0 R08: 0000000000000020 R09: 0000000000000000
>  R10: 0000000000000078 R11: ffff986719f73e76 R12: 0000000000001000
>  R13: 00000000ffffffea R14: 0000000054000fb0 R15: 0000000000000000
>  FS:  00000000028c2880(0000) GS:ffffffffa06ad000(0000) knlGS:0000000000000000
>  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  CR2: 0000000677846439 CR3: 0000000019fc1005 CR4: 00000000000606b0
>  Call Trace:
>   ? ipc_update_pid+0x36/0x3e
>   ? newseg+0x34c/0x3a6
>   ? ipcget+0x5d/0x528
>   ? entry_SYSCALL_64_after_hwframe+0x52/0xb7
>   ? SyS_shmget+0x5a/0x84
>   ? do_syscall_64+0x194/0x1b3
>   ? entry_SYSCALL_64_after_hwframe+0x42/0xb7
>  Code: ff 05 e7 20 9b 03 58 c9 c3 48 ff 05 85 21 9b 03 48 85 ff 74 4f 8b 47 04 8b 17 48 ff 05 7c 21 9b 03 48 83 c0 03 48 c1 e0 04 ff ca <48> 8b 44 07 08 74 1f 48 ff 05 6c 21 9b 03 ff 0f 0f 94 c2 48 ff
>  RIP: put_pid+0x22/0x5c RSP: ffff986719f73e48
>  CR2: 0000000677846439
>  ---[ end trace ab8c5cb4389d37c5 ]---
>  Kernel panic - not syncing: Fatal exception

In newseg when changing shm_cprid and shm_lprid from pid_t to struct
pid* I misread the kvmalloc as kvzalloc and thought shp was
initialized to 0.  As that is not the case it is not safe to for the
error handling to address shm_cprid and shm_lprid before they are
initialized.

Therefore move the cleanup of shm_cprid and shm_lprid from the no_file
error cleanup path to the no_id error cleanup path.  Ensuring that an
early error exit won't cause the oops above.

Reported-by: kernel test robot <fengguang.wu@intel.com>
Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2018-03-28 16:40:08 -05:00
Eric W. Biederman 50ab44b1c5 ipc: Directly call the security hook in ipc_ops.associate
After the last round of cleanups the shm, sem, and msg associate
operations just became trivial wrappers around the appropriate security
method.  Simplify things further by just calling the security method
directly.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-27 15:53:56 -05:00
Eric W. Biederman 51d6f2635b ipc/sem: Fix semctl(..., GETPID, ...) between pid namespaces
Today the last process to update a semaphore is remembered and
reported in the pid namespace of that process.  If there are processes
in any other pid namespace querying that process id with GETPID the
result will be unusable nonsense as it does not make any
sense in your own pid namespace.

Due to ipc_update_pid I don't think you will be able to get System V
ipc semaphores into a troublesome cache line ping-pong.  Using struct
pids from separate process are not a problem because they do not share
a cache line.  Using struct pid from different threads of the same
process are unlikely to be a problem as the reference count update
can be avoided.

Further linux futexes are a much better tool for the job of mutual
exclusion between processes than System V semaphores.  So I expect
programs that  are performance limited by their interprocess mutual
exclusion primitive will be using futexes.

So while it is possible that enhancing the storage of the last
rocess of a System V semaphore from an integer to a struct pid
will cause a performance regression because of the effect
of frequently updating the pid reference count.  I don't expect
that to happen in practice.

This change updates semctl(..., GETPID, ...) to return the
process id of the last process to update a semphore inthe
pid namespace of the calling process.

Fixes: b488893a39 ("pid namespaces: changes to show virtual ids to user")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-27 15:53:55 -05:00
Eric W. Biederman 39a4940eaa ipc/msg: Fix msgctl(..., IPC_STAT, ...) between pid namespaces
Today msg_lspid and msg_lrpid are remembered in the pid namespace of
the creator and the processes that last send or received a sysvipc
message.  If you have processes in multiple pid namespaces that is
just wrong.  The process ids reported will not make the least bit of
sense.

This fix is slightly more susceptible to a performance problem than
the related fix for System V shared memory.  By definition the pids
are updated by msgsnd and msgrcv, the fast path of System V message
queues.  The only concern over the previous implementation is the
incrementing and decrementing of the pid reference count.  As that is
the only difference and multiple updates by of the task_tgid by
threads in the same process have been shown in af_unix sockets to
create a cache line ping-pong between cpus of the same processor.

In this case I don't expect cache lines holding pid reference counts
to ping pong between cpus.  As senders and receivers update different
pids there is a natural separation there.  Further if multiple threads
of the same process either send or receive messages the pid will be
updated to the same value and ipc_update_pid will avoid the reference
count update.

Which means in the common case I expect msg_lspid and msg_lrpid to
remain constant, and reference counts not to be updated when messages
are sent.

In rare cases it may be possible to trigger the issue which was
observed for af_unix sockets, but it will require multiple processes
with multiple threads to be either sending or receiving messages.  It
just does not feel likely that anyone would do that in practice.

This change updates msgctl(..., IPC_STAT, ...) to return msg_lspid and
msg_lrpid in the pid namespace of the process calling stat.

This change also updates cat /proc/sysvipc/msg to return print msg_lspid
and msg_lrpid in the pid namespace of the process that opened the proc
file.

Fixes: b488893a39 ("pid namespaces: changes to show virtual ids to user")
Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-27 15:53:41 -05:00
Eric W. Biederman 98f929b1bd ipc/shm: Fix shmctl(..., IPC_STAT, ...) between pid namespaces.
Today shm_cpid and shm_lpid are remembered in the pid namespace of the
creator and the processes that last touched a sysvipc shared memory
segment.   If you have processes in multiple pid namespaces that
is just wrong, and I don't know how this has been over-looked for
so long.

As only creation and shared memory attach and shared memory detach
update the pids I do not expect there to be a repeat of the issues
when struct pid was attached to each af_unix skb, which in some
notable cases cut the performance in half.  The problem was threads of
the same process updating same struct pid from different cpus causing
the cache line to be highly contended and bounce between cpus.

As creation, attach, and detach are expected to be rare operations for
sysvipc shared memory segments I do not expect that kind of cache line
ping pong to cause probems.  In addition because the pid is at a fixed
location in the structure instead of being dynamic on a skb, the
reference count of the pid does not need to be updated on each
operation if the pid is the same.  This ability to simply skip the pid
reference count changes if the pid is unchanging further reduces the
likelihood of the a cache line holding a pid reference count
ping-ponging between cpus.

Fixes: b488893a39 ("pid namespaces: changes to show virtual ids to user")
Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-27 15:53:09 -05:00
Eric W. Biederman cfb2f6f6e0 Revert "mqueue: switch to on-demand creation of internal mount"
This reverts commit 36735a6a2b.

Aleksa Sarai <asarai@suse.de> writes:
> [REGRESSION v4.16-rc6] [PATCH] mqueue: forbid unprivileged user access to internal mount
>
> Felix reported weird behaviour on 4.16.0-rc6 with regards to mqueue[1],
> which was introduced by 36735a6a2b ("mqueue: switch to on-demand
> creation of internal mount").
>
> Basically, the reproducer boils down to being able to mount mqueue if
> you create a new user namespace, even if you don't unshare the IPC
> namespace.
>
> Previously this was not possible, and you would get an -EPERM. The mount
> is the *host* mqueue mount, which is being cached and just returned from
> mqueue_mount(). To be honest, I'm not sure if this is safe or not (or if
> it was intentional -- since I'm not familiar with mqueue).
>
> To me it looks like there is a missing permission check. I've included a
> patch below that I've compile-tested, and should block the above case.
> Can someone please tell me if I'm missing something? Is this actually
> safe?
>
> [1]: https://github.com/docker/docker/issues/36674

The issue is a lot deeper than a missing permission check.  sb->s_user_ns
was is improperly set as well.  So in addition to the filesystem being
mounted when it should not be mounted, so things are not allow that should
be.

We are practically to the release of 4.16 and there is no agreement between
Al Viro and myself on what the code should looks like to fix things properly.
So revert the code to what it was before so that we can take our time
and discuss this properly.

Fixes: 36735a6a2b ("mqueue: switch to on-demand creation of internal mount")
Reported-by: Felix Abecassis <fabecassis@nvidia.com>
Reported-by: Aleksa Sarai <asarai@suse.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-24 19:34:23 -05:00
Eric W. Biederman 03f1fc0918 ipc/util: Helpers for making the sysvipc operations pid namespace aware
Capture the pid namespace when /proc/sysvipc/msg /proc/sysvipc/shm
and /proc/sysvipc/sem are opened, and make it available through
the new helper ipc_seq_pid_ns.

This makes it possible to report the pids in these files in the
pid namespace of the opener of the files.

Implement ipc_update_pid.  A simple impline helper that will only update
a struct pid pointer if the new value does not equal the old value.  This
removes the need for wordy code sequences like:

	old = object->pid;
	object->pid = new;
	put_pid(old);

and

	old = object->pid;
	if (old != new) {
		object->pid = new;
		put_pid(old);
	}

Allowing the following to be written instead:

	ipc_update_pid(&object->pid, new);

Which is easier to read and ensures that the pid reference count is
not touched the old and the new values are the same.  Not touching
the reference count in this case is important to help avoid issues
like af_unix experienced, where multiple threads of the same
process managed to bounce the struct pid between cpu cache lines,
but updating the pids reference count.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-24 11:25:37 -05:00
Eric W. Biederman f83a396d06 ipc: Move IPCMNI from include/ipc.h into ipc/util.h
The definition IPCMNI is only used in ipc/util.h and ipc/util.c.  So
there is no reason to keep it in a header file that the whole kernel
can see.  Move it into util.h to simplify future maintenance.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-24 11:25:36 -05:00
Eric W. Biederman 34b56df922 msg: Move struct msg_queue into ipc/msg.c
All of the users are now in ipc/msg.c so make the definition local to
that file to make code maintenance easier.  AKA to prevent rebuilding
the entire kernel when struct msg_queue changes.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-24 11:25:35 -05:00
Eric W. Biederman a2e102cd3c shm: Move struct shmid_kernel into ipc/shm.c
All of the users are now in ipc/shm.c so make the definition local to
that file to make code maintenance easier.  AKA to prevent rebuilding
the entire kernel when struct shmid_kernel changes.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-24 11:25:21 -05:00
Eric W. Biederman 1a5c1349d1 sem: Move struct sem and struct sem_array into ipc/sem.c
All of the users are now in ipc/sem.c so make the definitions
local to that file to make code maintenance easier.  AKA
to prevent rebuilding the entire kernel when one of these
files is changed.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22 21:30:56 -05:00
Eric W. Biederman d8c6e85432 msg/security: Pass kern_ipc_perm not msg_queue into the msg_queue security hooks
All of the implementations of security hooks that take msg_queue only
access q_perm the struct kern_ipc_perm member.  This means the
dependencies of the msg_queue security hooks can be simplified by
passing the kern_ipc_perm member of msg_queue.

Making this change will allow struct msg_queue to become private to
ipc/msg.c.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22 21:22:26 -05:00
Eric W. Biederman 7191adff2a shm/security: Pass kern_ipc_perm not shmid_kernel into the shm security hooks
All of the implementations of security hooks that take shmid_kernel only
access shm_perm the struct kern_ipc_perm member.  This means the
dependencies of the shm security hooks can be simplified by passing
the kern_ipc_perm member of shmid_kernel..

Making this change will allow struct shmid_kernel to become private to ipc/shm.c.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22 21:08:27 -05:00
Eric W. Biederman aefad9593e sem/security: Pass kern_ipc_perm not sem_array into the sem security hooks
All of the implementations of security hooks that take sem_array only
access sem_perm the struct kern_ipc_perm member.  This means the
dependencies of the sem security hooks can be simplified by passing
the kern_ipc_perm member of sem_array.

Making this change will allow struct sem and struct sem_array
to become private to ipc/sem.c.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22 21:07:51 -05:00
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00
Jonathan Haws 68e34f4e89 ipc/mqueue.c: have RT tasks queue in by priority in wq_add()
Previous behavior added tasks to the work queue using the static_prio
value instead of the dynamic priority value in prio.  This caused RT tasks
to be added to the work queue in a FIFO manner rather than by priority.
Normal tasks were handled by priority.

This fix utilizes the dynamic priority of the task to ensure that both RT
and normal tasks are added to the work queue in priority order.  Utilizing
the dynamic priority (prio) rather than the base priority (normal_prio)
was chosen to ensure that if a task had a boosted priority when it was
added to the work queue, it would be woken sooner to to ensure that it
releases any other locks it may be holding in a more timely manner.  It is
understood that the task could have a lower priority when it wakes than
when it was added to the queue in this (unlikely) case.

Link: http://lkml.kernel.org/r/1513006652-7014-1-git-send-email-jhaws@sdl.usu.edu
Signed-off-by: Jonathan Haws <jhaws@sdl.usu.edu>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:46 -08:00
Philippe Mikoyan 87ad4b0d85 ipc: fix ipc data structures inconsistency
As described in the title, this patch fixes <ipc>id_ds inconsistency when
<ipc>ctl_stat executes concurrently with some ds-changing function, e.g.
shmat, msgsnd or whatever.

For instance, if shmctl(IPC_STAT) is running concurrently
with shmat, following data structure can be returned:
{... shm_lpid = 0, shm_nattch = 1, ...}

Link: http://lkml.kernel.org/r/20171202153456.6514-1-philippe.mikoyan@skat.systems
Signed-off-by: Philippe Mikoyan <philippe.mikoyan@skat.systems>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:46 -08:00
Linus Torvalds 8b0fdf631c Merge branch 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull mqueue/bpf vfs cleanups from Al Viro:
 "mqueue and bpf go through rather painful and similar contortions to
  create objects in their dentry trees. Provide a primitive for doing
  that without abusing ->mknod(), switch bpf and mqueue to it.

  Another mqueue-related thing that has ended up in that branch is
  on-demand creation of internal mount (based upon the work of Giuseppe
  Scrivano)"

* 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  mqueue: switch to on-demand creation of internal mount
  tidy do_mq_open() up a bit
  mqueue: clean prepare_open() up
  do_mq_open(): move all work prior to dentry_open() into a helper
  mqueue: fold mq_attr_ok() into mqueue_get_inode()
  move dentry_open() calls up into do_mq_open()
  mqueue: switch to vfs_mkobj(), quit abusing ->d_fsdata
  bpf_obj_do_pin(): switch to vfs_mkobj(), quit abusing ->mknod()
  new primitive: vfs_mkobj()
2018-01-30 18:32:21 -08:00
Linus Torvalds 168fe32a07 Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull poll annotations from Al Viro:
 "This introduces a __bitwise type for POLL### bitmap, and propagates
  the annotations through the tree. Most of that stuff is as simple as
  'make ->poll() instances return __poll_t and do the same to local
  variables used to hold the future return value'.

  Some of the obvious brainos found in process are fixed (e.g. POLLIN
  misspelled as POLL_IN). At that point the amount of sparse warnings is
  low and most of them are for genuine bugs - e.g. ->poll() instance
  deciding to return -EINVAL instead of a bitmap. I hadn't touched those
  in this series - it's large enough as it is.

  Another problem it has caught was eventpoll() ABI mess; select.c and
  eventpoll.c assumed that corresponding POLL### and EPOLL### were
  equal. That's true for some, but not all of them - EPOLL### are
  arch-independent, but POLL### are not.

  The last commit in this series separates userland POLL### values from
  the (now arch-independent) kernel-side ones, converting between them
  in the few places where they are copied to/from userland. AFAICS, this
  is the least disruptive fix preserving poll(2) ABI and making epoll()
  work on all architectures.

  As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and
  it will trigger only on what would've triggered EPOLLWRBAND on other
  architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered
  at all on sparc. With this patch they should work consistently on all
  architectures"

* 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
  make kernel-side POLL... arch-independent
  eventpoll: no need to mask the result of epi_item_poll() again
  eventpoll: constify struct epoll_event pointers
  debugging printk in sg_poll() uses %x to print POLL... bitmap
  annotate poll(2) guts
  9p: untangle ->poll() mess
  ->si_band gets POLL... bitmap stored into a user-visible long field
  ring_buffer_poll_wait() return value used as return value of ->poll()
  the rest of drivers/*: annotate ->poll() instances
  media: annotate ->poll() instances
  fs: annotate ->poll() instances
  ipc, kernel, mm: annotate ->poll() instances
  net: annotate ->poll() instances
  apparmor: annotate ->poll() instances
  tomoyo: annotate ->poll() instances
  sound: annotate ->poll() instances
  acpi: annotate ->poll() instances
  crypto: annotate ->poll() instances
  block: annotate ->poll() instances
  x86: annotate ->poll() instances
  ...
2018-01-30 17:58:07 -08:00
Eric W. Biederman faf1f22b61 signal: Ensure generic siginfos the kernel sends have all bits initialized
Call clear_siginfo to ensure stack allocated siginfos are fully
initialized before being passed to the signal sending functions.

This ensures that if there is the kind of confusion documented by
TRAP_FIXME, FPE_FIXME, or BUS_FIXME the kernel won't send unitialized
data to userspace when the kernel generates a signal with SI_USER but
the copy to userspace assumes it is a different kind of signal, and
different fields are initialized.

This also prepares the way for turning copy_siginfo_to_user
into a copy_to_user, by removing the need in many cases to perform
a field by field copy simply to skip the uninitialized fields.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-12 14:21:07 -06:00
Al Viro 36735a6a2b mqueue: switch to on-demand creation of internal mount
Instead of doing that upon each ipcns creation, we do that the first
time mq_open(2) or mqueue mount is done in an ipcns.  What's more,
doing that allows to get rid of mount_ns() use - we can go with
considerably cheaper mount_nodev(), avoiding the loop over all
mqueue superblock instances; ipcns->mq_mnt is used to locate preexisting
instance in O(1) time instead of O(instances) mount_ns() would've
cost us.

Based upon the version by Giuseppe Scrivano <gscrivan@redhat.com>; I've
added handling of userland mqueue mounts (original had been broken in
that area) and added a switch to mount_nodev().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:54:37 -05:00
Al Viro a713fd7f52 tidy do_mq_open() up a bit
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:54:36 -05:00
Al Viro 9b20d7fc52 mqueue: clean prepare_open() up
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:54:36 -05:00
Al Viro 066cc813e9 do_mq_open(): move all work prior to dentry_open() into a helper
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:54:35 -05:00
Al Viro 05c1b29038 mqueue: fold mq_attr_ok() into mqueue_get_inode()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:54:35 -05:00
Al Viro af4a5372e4 move dentry_open() calls up into do_mq_open()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:54:34 -05:00
Al Viro eecec19d9e mqueue: switch to vfs_mkobj(), quit abusing ->d_fsdata
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-05 11:54:33 -05:00
Al Viro 9dd957485d ipc, kernel, mm: annotate ->poll() instances
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-27 16:20:05 -05:00
Linus Torvalds 1751e8a6cb Rename superblock flags (MS_xyz -> SB_xyz)
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 <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-27 13:05:09 -08:00
Linus Torvalds fa7f578076 Merge branch 'akpm' (patches from Andrew)
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 <akpm@linux-foundation.org>: (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
  ...
2017-11-17 16:56:17 -08:00
Davidlohr Bueso 15df03c879 sysvipc: make get_maxid O(1) again
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 7ca7e564e0 ("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 <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:04 -08:00
Davidlohr Bueso ebf66799ac sysvipc: properly name ipc_addid() limit parameter
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 <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:04 -08:00