There's a race between mm->owner assignment and swapoff, more easily
seen when task slab poisoning is turned on.  The condition occurs when
try_to_unuse() runs in parallel with an exiting task.  A similar race
can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats>
or ptrace or page migration.

CPU0                                    CPU1
                                        try_to_unuse
                                        looks at mm = task0->mm
                                        increments mm->mm_users
task 0 exits
mm->owner needs to be updated, but no
new owner is found (mm_users > 1, but
no other task has task->mm = task0->mm)
mm_update_next_owner() leaves
                                        mmput(mm) decrements mm->mm_users
task0 freed
                                        dereferencing mm->owner fails

The fix is to notify the subsystem via mm_owner_changed callback(),
if no new owner is found, by specifying the new task as NULL.

Jiri Slaby:
mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but
must be set after that, so as not to pass NULL as old owner causing oops.

Daisuke Nishimura:
mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task()
and its callers need to take account of this situation to avoid oops.

Hugh Dickins:
Lockdep warning and hang below exec_mmap() when testing these patches.
exit_mm() up_reads mmap_sem before calling mm_update_next_owner(),
so exec_mmap() now needs to do the same.  And with that repositioning,
there's now no point in mm_need_new_owner() allowing for NULL mm.
Reported-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: disable apm on the olpc

* git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6:
  cdrom: update ioctl documentation
  ide: note that IDE generic may prevent other drivers from attaching
  ide-tape: fix vendor strings
  Swarm: Fix crash due to missing initialization

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  [SSB] Initialise dma_mask for SSB_BUSTYPE_SSB devices
  [MIPS] BCM47xx: Fix build error due to missing PCI functions
  [MIPS] IP27: Switch to dynamic interrupt routing avoding panic on error.
  [MIPS] au1000: Make sure GPIO value is zero or one

* 'linux-m32r' of git://www.linux-m32r.org/git/takata/linux-2.6_dev:
  m32r/kernel/: cleanups
  m32r: export __ndelay
  m32r: export empty_zero_page
  m32r: don't offer CONFIG_ISA
  m32r: remove the unused NOHIGHMEM option

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kgdboc,tty: Fix tty polling search to use name correctly
  kgdb, x86_64: fix PS CS SS registers in gdb serial
  kgdb, x86_64: gdb serial has BX and DX reversed
  kgdb, x86, arm, mips, powerpc: ignore user space single stepping
  kgdb: could not write to the last of valid memory with kgdb

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ALSA: ASoC: Fix another cs4270 error path
  ALSA: make the CS4270 driver a new-style I2C driver

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6:
  [SCSI] qlogicpti: fix sg list traversal error in continuation entries
  [SCSI] Fix hang with split requests
  [SCSI] qla2xxx: Defer enablement of RISC interrupts until ISP initialization completes.

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  scsi: fix fall out of sg-chaining patch in qlogicpti

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  sata_nv: reinstate nv_hardreset() for non generic controllers

Commit f072181e ("kconfig: drop the
""trying to assign nonexistent symbol" warning") simply dropped the
warnings, but it does a little more than that, it also marks the current
.config as needed saving, so add this back.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Recent changes to oldconfig have mixed up the silentoldconfig handling,
so this fixes that by clearly separating that special mode, e.g.
KCONFIG_NOSILENTUPDATE is only relevant here, the .config is written as
needed.

This will also properly close Bug 11230.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The VFS interface for the 'd_compare()' is a bit special (read: 'odd'),
because it really just essentially replaces a memcmp().  The filesystem
is supposed to just compare the two names with whatever case-independent
or other function.

And when I say 'is supposed to', I obviously mean that 'procfs does odd
things, and actually looks at the dentry that we don't even pass down,
rather than just the name'.  Which results in problems, because we
actually call d_compare before we have even verified that the dentry is
still hashed at all.

And that causes a problm since the inode that procfs looks at may have
been free'd and the d_inode pointer is NULL.  procfs just assumes that
all dentries are positive, since procfs itself never generates a
negative one.  But memory pressure will still result in the dentry
getting torn down, and as it is removed by RCU, it still remains visible
on some lists - and to d_compare.

If the filesystem just did a name comparison, we wouldn't care.  And we
could just fix procfs to know about negative dentries too.  But rather
than have the low-level filesystems know about internal VFS details,
just move the check for a unhashed dentry up a bit, so that we will only
call d_compare on dentries that are still active.

The actual oops this caused didn't look like a NULL pointer dereference
because procfs did a 'container_of(inode, struct proc_inode, vfs_inode)'
to get at its internal proc_inode information from the inode pointer,
and accessed a field below the inode. So the oops would look something
like

	BUG: unable to handle kernel paging request at fffffffffffffff0
	IP: [<ffffffff802bc6c6>] proc_sys_compare+0x36/0x50

and was seen on both x86-64 (Alexey Dobriyan and Hugh Dickins) and
ppc64 (Hugh Dickins).
Reported-by: NAlexey Dobriyan <adobriyan@gmail.com>
Acked-by: NHugh Dickins <hugh@veritas.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-of-by: NLinus Torvalds <torvalds@linux-foundation.org>

Conversion to new-style i2c driver missed the error path of the
probe function. Fix it.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Timur Tabi <timur@freescale.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Update the CS4270 ALSA device driver to use the new-style I2C interface.
Starting with the 2.6.27 PowerPC kernel, I2C devices that have entries in the
device trees can no longer be probed by old-style I2C drivers.  The device
tree for Freescale MPC8610 HPCD has included an entry for the CS4270 since
2.6.25, but that entry was previously ignored by the PowerPC I2C subsystem.
Since that's no longer the case, the best solution is to update the CS4270
driver to a new-style interface, rather than try to revert the behavior of
new PowerPC I2C subsystem.
Signed-off-by: NTimur Tabi <timur@freescale.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Boaz writes:

"I've reviewed all patches since Matthew's, and I find one small
problem.

In the load_cmd() there is a compound loop where the first 4 sg's are
set then the rest are set into a memory structure in group of 7 sg's.

Well the second 7-group and on is a bug because sg pointer does not advance.
This is a fall out from Jens's patch."

The reporter, Meelis Roos <mroos@ut.ee>, verified that this patch
does indeed fix his problem with qlogicpti.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Commit 2fd673ec which tried to remove
hardreset for generic accidentally removed it for all flavors as all
others were inheriting from nv_generic_ops.  This patch reinstates
nv_hardreset() and puts it into nv_common_ops which all flavors
inherit from.  nv_generic_ops now inherits from nv_common_ops and
overrides .hardreset to ATA_OP_NULL.

While at it, explain why nv_hardreset and ATA_OP_NULL override are
necessary.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

The current sg list traversal logic for the continuation entries
doesn't advance the list pointer once all seven slots are used, so the
next continuation entry (if there is one) wrongly begins again at the
start of the sg list.

Fix by advancing the sg pointer after the for_each_sg().
Reported-by: NMeelis Roos <mroos@ut.ee>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Correct copy-paste problem: CDROMCLOSETRAY is about closing the tray,
not opening it.
Signed-off-by: NMárton Németh <nm127@freemail.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Enabling IDE generic may prevent ATA controllers located on legacy
ports from being attached to more proper driver or can prevent other
controllers which share the IRQ from working.  Note it in the help
message.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: xerces8 <xerces8@butn.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: stein@hermes.si
[bart: s/will grab/may grab/ since Borislav has fixed PCI-case for .28]
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Remove superfluous two bytes from each string buffer and add proper length
format specifiers.
Signed-off-by: NBorislav Petkov <petkovbb@gmail.com>
Tested-by: NMark de Wever <koraq@xs4all.nl>
Acked-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

If things are just right this will result in the hws[0]->parent being
passed to ide_host_add() being non-zero and an ooops a little later.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

For SSB_BUSTYPE_SSB type devices, we need to initialize dma_mask using
coherent_dma_mask so that calls to dma_set_mask() succeed.

It fixes the regression on the b44 driver introduced by commit
f225763aSigned-off-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This patch defines pcibios_map_irq() and pcibios_plat_dev_init() for
the BCM47xx platform.

It fixes the regression introduced by commit
aab547ce.
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

pcibios_map_irq is no way of returning an error but on IP27 an interrupt
is possibly not routable when running out of resources.  So do the
interrupt routing at pcibios_enable_device time.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

David Brownell <david-b@pacbell.net> wrote:
>       The problem is that "value" is zero-or-nonzero.
>       This code wrongly assumes it's zero-or-one.
>       Possible fix:  "((!!value) << gpio)".
Signed-off-by: NBruno Randolf <br1@einfach.org>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This patch contains the following cleanups:
- make the following needlessly global code static:
  - entry.S: resume_userspace
  - process.c: pm_idle
  - process.c: default_idle()
  - smp.c: send_IPI_allbutself()
  - time.c: timer_interrupt()
  - time.c: struct irq0
  - traps.c: set_eit_vector_entries()
  - traps.c: kstack_depth_to_print
  - traps.c: show_trace()
  - traps.c: die_lock
- remove the following unused code:
  - head.S: startup_32
  - process.c: hlt_counter
  - process.c: disable_hlt()
  - process.c: enable_hlt()
  - process.c: dump_task_regs()
- remove the following variables and their usages since they were
  always 0:
  - irq.c: irq_err_count
  - irq.c: irq_mis_count
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>

ERROR: "__ndelay" [drivers/spi/spi_bitbang.ko] undefined!
Reported-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>

ERROR: "empty_zero_page" [fs/ext4/ext4dev.ko] undefined!
Reported-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>

As far as I know no M32R hardware actually has ISA slots.

And ISA drivers don't compile on M32R.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>

Remove the unused NOHIGHMEM option.
Reviewed-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHirokazu Takata <takata@linux-m32r.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ALSA: remove unneeded power_mutex lock in snd_pcm_drop
  ALSA: fix locking in snd_pcm_open*() and snd_rawmidi_open*()

* git://oss.sgi.com:8090/xfs/linux-2.6:
  [XFS] Remove xfs_iext_irec_compact_full()
  [XFS] Fix extent list corruption in xfs_iext_irec_compact_full().

Delete ARM's own cnt32_to_63.h as the copy in include/linux/ should now be
used instead.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The tty_find_polling_driver() routine did not correctly check the base
part of the tty name.  This can lead to kgdboc selecting an incorrect
driver, as well as accepting a completely invalid tty such as "echo
ffff0 > /sys/module/kgdboc/parameters/kgdboc".
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

On x86_64 the gdb serial register structure defines the PS (also known
as eflags), CS and SS registers as 4 bytes entities.

This patch splits the x86_64 regnames enum into a 32 and 64 version to
account for the 32 bit entities in the gdb serial packets.

Also the program counter is properly filled in for the sleeping
threads.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

The BX and DX registers in the gdb serial register packet need to be
flipped for gdb to receive the correct data.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

On the x86 arch, user space single step exceptions should be ignored
if they occur in the kernel space, such as ptrace stepping through a
system call.

First check if it is kgdb that is executing a single step, then ensure
it is not an accidental traversal into the user space, while in kgdb,
any other time the TIF_SINGLESTEP is set, kgdb should ignore the
exception.

On x86, arm, mips and powerpc, the kgdb_contthread usage was
inconsistent with the way single stepping is implemented in the kgdb
core.  The arch specific stub should always set the
kgdb_cpu_doing_single_step correctly if it is single stepping.  This
allows kgdb to correctly process an instruction steps if ptrace
happens to be requesting an instruction step over a system call.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

On the ARM architecture, kgdb will crash the kernel if the last byte
of valid memory is written due to a flush_icache_range flushing
beyond the memory boundary.
Signed-off-by: NAtsuo Igarashi <atsuo_igarashi@tripeaks.co.jp>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>