ACPI 4.0 spec adds the ACPI IPMI opregion, which means that the ACPI AML
code can also communicate with the BMC controller. This is to install
the ACPI IPMI opregion and enable the ACPI to access the BMC controller
through the IPMI message.

     It will create IPMI user interface for every IPMI device detected
in ACPI namespace and install the corresponding IPMI opregion space handler.
Then it can enable ACPI to access the BMC controller through the IPMI
message.

The following describes how to process the IPMI request in IPMI space handler:
    1. format the IPMI message based on the request in AML code.
    IPMI system address. Now the address type is SYSTEM_INTERFACE_ADDR_TYPE
    IPMI net function & command
    IPMI message payload
    2. send the IPMI message by using the function of ipmi_request_settime
    3. wait for the completion of IPMI message. It can be done in different
routes: One is in handled in IPMI user recv callback function. Another is
handled in timeout function.
    4. format the IPMI response and return it to ACPI AML code.

At the same time it also addes the module dependency. The ACPI IPMI opregion
will depend on the IPMI subsystem.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Add the document description about how to use ipmi_get_smi_info.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Len Brown <len.brown@intel.com>

The IPMI smi_watcher will be used to catch the IPMI interface as they
come or go.  In order to communicate with the correct IPMI device, it
should be confirmed whether it is what we wanted especially on the
system with multiple IPMI devices. But the new_smi callback function
of smi_watcher provides very limited info(only the interface number
and dev pointer) and there is no detailed info about the low level
interface. For example: which mechansim registers the IPMI
interface(ACPI, PCI, DMI and so on).

This is to add one interface that can get more info of low-level IPMI
device. For example: the ACPI device handle will be returned for the
pnp_acpi IPMI device.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Len Brown <len.brown@intel.com>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
  ocfs2_connection_find() returns pointer to bad structure
  ocfs2: char is not always signed
  Ocfs2: Stop tracking a negative dentry after dentry_iput().
  ocfs2: fix memory leak
  fs/ocfs2/dlm: Use GFP_ATOMIC under spin_lock

Commit 0ea12930 ("arm: return both physical and virtual addresses
from addruart") took out the test for MMU on/off but didn't switch the
ldr instructions to no longer be conditionals based on said test.

Fix that.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  PM / Hibernate: Fix memory corruption related to swap
  PM / Hibernate: Use async I/O when reading compressed hibernation image

There is a problem that swap pages allocated before the creation of
a hibernation image can be released and used for storing the contents
of different memory pages while the image is being saved.  Since the
kernel stored in the image doesn't know of that, it causes memory
corruption to occur after resume from hibernation, especially on
systems with relatively small RAM that need to swap often.

This issue can be addressed by keeping the GFP_IOFS bits clear
in gfp_allowed_mask during the entire hibernation, including the
saving of the image, until the system is finally turned off or
the hibernation is aborted.  Unfortunately, for this purpose
it's necessary to rework the way in which the hibernate and
suspend code manipulates gfp_allowed_mask.

This change is based on an earlier patch from Hugh Dickins.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Ondrej Zary <linux@rainbow-software.org>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: stable@kernel.org

* master.kernel.org:/home/rmk/linux-2.6-arm:
  ARM: 6524/1: GIC irq desciptor bug fix
  ARM: 6523/1: iop: ensure sched_clock() is notrace
  ARM: 6456/1: Fix for building DEBUG with sa11xx_base.c as a module.
  ARM: 6519/1: kuser: Fix incorrect cmpxchg syscall in kuser helpers
  ARM: 6505/1: kprobes: Don't HAVE_KPROBES when CONFIG_THUMB2_KERNEL is selected
  ARM: 6508/1: vexpress: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
  ARM: 6507/1: RealView: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
  ARM: 6504/1: Thumb-2: Fix long-distance conditional branches in head.S for Thumb-2.
  ARM: 6503/1: Thumb-2: Restore sensible zImage header layout for CONFIG_THUMB2_KERNEL
  ARM: 6502/1: Thumb-2: Fix CONFIG_THUMB2_KERNEL breakage in compressed/head.S
  ARM: 6501/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in mm/proc-v7.S
  ARM: 6500/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in kernel/head.S
  ARM: 6499/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in bootp/init.S
  ARM: 6498/1: vfp: Correct data alignment for CONFIG_THUMB2_KERNEL
  ARM: 6497/1: kexec: Correct data alignment for CONFIG_THUMB2_KERNEL
  ARM: 6496/1: GIC: Do not try to register more then NR_IRQS interrupts
  ARM: cns3xxx: Fix build with CONFIG_PCI=y

This is a fix for reading LZO compressed image using async I/O.
Essentially, instead of having just one page into which we keep
reading blocks from swap, we allocate enough of them to cover the
largest compressed size and then let block I/O pick them all up. Once
we have them all (and here we wait), we decompress them, as usual.
Obviously, the very first block we still pick up synchronously,
because we need to know the size of the lot before we pick up the
rest.

Also fixed the copyright line, which I've forgotten before.
Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

gic_set_cpu will directly use irq_desc[]. If CONFIG_SPARSE_IRQ is
enabled, there is no irq_desc[]. So we need use irq_to_desc(irq) to
get the descriptor for irq.
Signed-off-by: Chao Xie <chao.xie@marvell.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slub: Fix a crash during slabinfo -v

* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  initramfs: Really fix build break on symbol-prefixed archs
  [media] Fix Kconfig errors due to two visible menus
  i2c/algos: convert Kconfig to use the menu's `visible' keyword
  media/video: convert Kconfig to use the menu's `visible' keyword
  Revert "i2c: Fix Kconfig dependencies"
  kconfig: regen parser
  kconfig: add an option to determine a menu's visibility

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kyle/parisc-2.6:
  parisc: Fix GSC PS/2 driver name for keyboard and mouse
  parisc: KittyHawk LCD fix
  parisc: convert the rest of the irq handlers to simple/percpu
  parisc: fix dino/gsc interrupts
  parisc: remove redundant initialization in sigsegv path of sys_rt_sigreturn

Because it caused a chroot ttyname regression in 2.6.36.

As of 2.6.36 ttyname does not work in a chroot.  It has already been
reported that screen breaks, and for me this breaks an automated
distribution testsuite, that I need to preserve the ability to run the
existing binaries on for several more years.  glibc 2.11.3 which has a
fix for this is not an option.

The root cause of this breakage is:

    commit 8df9d1a4
    Author: Miklos Szeredi <mszeredi@suse.cz>
    Date:   Tue Aug 10 11:41:41 2010 +0200

    vfs: show unreachable paths in getcwd and proc

    Prepend "(unreachable)" to path strings if the path is not reachable
    from the current root.

    Two places updated are
     - the return string from getcwd()
     - and symlinks under /proc/$PID.

    Other uses of d_path() are left unchanged (we know that some old
    software crashes if /proc/mounts is changed).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

So remove the nice sounding, but ultimately ill advised change to how
/proc/fd symlinks work.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix kernel warnings caused by the driver name of GSC PS/2 containing '/'.

The following warnings are observed on a K410 system :

[   10.700000] name 'GSC PS/2 keyboard'
[   10.732000] ------------[ cut here ]------------
[   10.772000] WARNING: at fs/proc/generic.c:323
[   10.828000] Modules linked in:
[   10.916000]
[   10.916000]      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
[   10.936000] PSW: 00000000000001000000000000001111 Not tainted
[   10.992000] r00-03  0004000f 104fe3e0 10201ea0 00000000
[   11.060000] r04-07  4fc405c8 00000006 4fc405c8 4fc40694
[   11.124000] r08-11  4fc40708 10438aa0 00000001 1043bfc8
[   11.184000] r12-15  104ff2a0 104ff2a0 4fc38634 104ff2a0
[   11.248000] r16-19  f0001570 10479af0 f000006c 1044fe50
[   11.308000] r20-23  00000000 00000028 104cd858 00000000
[   11.372000] r24-27  ffffffff 0000000e 1044fe10 1043bbe0
[   11.436000] r28-31  0000002b 00000078 4fc40800 0000000d
[   11.496000] sr00-03  00000000 00000000 00000000 00000000
[   11.560000] sr04-07  00000000 00000000 00000000 00000000
[   11.624000]
[   11.688000] IASQ: 00000000 00000000 IAOQ: 10201ea0 10201ea4
[   11.704000]  IIR: 03ffe01f    ISR: 00000000  IOR: 0000000d
[   11.772000]  CPU:        0   CR30: 4fc40000 CR31: f01043b0
[   11.836000]  ORIG_R28: 4fc40940
[   11.904000]  IAOQ[0]: __xlate_proc_name+0x90/0xd0
[   11.940000]  IAOQ[1]: __xlate_proc_name+0x94/0xd0
[   11.996000]  RP(r2): __xlate_proc_name+0x90/0xd0
[   12.052000] Backtrace:
[   12.108000]  [<10257790>] vsnprintf+0x290/0x4f4
[   12.136000]
[   12.188000] ---[ end trace 91bf6ece17e322dd ]---
[   12.208000] serio: GSC PS/2 keyboard port at 0x0001c000 irq 19 @ 10:12:7
[   12.264000] name 'GSC PS/2 mouse'
[   12.344000] ------------[ cut here ]------------
[   12.384000] WARNING: at fs/proc/generic.c:323
[   12.436000] Modules linked in:
[   12.524000]
[   12.528000]      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
[   12.544000] PSW: 00000000000001000000000000001111 Tainted: G        W
[   12.600000] r00-03  0004000f 104fe3e0 10201ea0 00000000
[   12.680000] r04-07  4fc405c8 00000006 4fc405c8 4fc40694
[   12.740000] r08-11  4fc40708 10438aa0 00000001 1043bfc8
[   12.804000] r12-15  104ff2a0 104ff2a0 4fc38634 104ff2a0
[   12.868000] r16-19  f0001570 10479af0 f000006c 1044fe50
[   12.928000] r20-23  00000000 00000025 104cd858 00000000
[   12.992000] r24-27  ffffffff 0000000e 1044fe10 1043bbe0
[   13.056000] r28-31  00000028 00000078 4fc40800 0000000d
[   13.116000] sr00-03  00000000 00000000 00000000 00000000
[   13.180000] sr04-07  00000000 00000000 00000000 00000000
[   13.244000]
[   13.308000] IASQ: 00000000 00000000 IAOQ: 10201ea0 10201ea4
[   13.324000]  IIR: 03ffe01f    ISR: 00000000  IOR: 0000000d
[   13.392000]  CPU:        0   CR30: 4fc40000 CR31: f01043b0
[   13.456000]  ORIG_R28: 4fc40940
[   13.524000]  IAOQ[0]: __xlate_proc_name+0x90/0xd0
[   13.560000]  IAOQ[1]: __xlate_proc_name+0x94/0xd0
[   13.616000]  RP(r2): __xlate_proc_name+0x90/0xd0
[   13.672000] Backtrace:
[   13.728000]  [<10257790>] vsnprintf+0x290/0x4f4
[   13.756000]
[   13.808000] ---[ end trace 91bf6ece17e322de ]---
[   13.828000] serio: GSC PS/2 mouse port at 0x00020100 irq 19 @ 10:12:8
Signed-off-by: Guy Martin <gmsoft@tuxicoman.be>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

K class aka KittyHawk don't have LED support on their LCD. Installing
HP-UX confirmed this. The current led_wq fills the LCD with black
characters each time it runs.

The patch prevents the led_wq workqueue and its proc entry to be
created for KittyHawk machines.

It also increase min_cmd_delay as currently, one character out of two
is lost when a string is sent to the LCD.
Signed-off-by: Guy Martin <gmsoft@tuxicoman.be>
Signed-off-by: Kyle McMartin <kyle@mcmartin.c>

The generic conversion eliminates the spurious no_ack and no_end
routines, converts all the cascaded handlers to handle_simple_irq() and
makes iosapic use a modified handle_percpu_irq() to become the same as
the CPU irq's.  This isn't an essential change, but it eliminates the
mask/unmask overhead of handle_level_irq().
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

The essential problem we're currently having is that dino (and gsc) is a
cascaded CPU interrupt.  Under the old __do_IRQ() handler, our CPU
interrupts basically did an ack followed by an end.  In the new scheme,
we replaced them with level handlers which do a mask, an ack and then an
unmask (but no end).  Instead, with the renaming of end to eoi, we
actually want to call the percpu flow handlers, because they actually
have all the characteristics we want.

This patch does the conversion and gets my C360 booting again.
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

Include sched.h to ensure sched_clock() has the notrace
annotation, and mark any functions it calls as notrace
too.
Include sched.h to ensure sched_clock() has the notrace
annotation, and mark any functions it calls as notrace
too.
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch fixes a compilation issue when compiling PCMCIA SA1100
support as a module with PCMCIA_DEBUG enabled. The symbol
soc_pcmcia_debug was not beeing exported.
ARM: pcmcia: Fix for building DEBUG with sa11xx_base.c as a module.

This patch fixes a compilation issue when compiling PCMCIA SA1100
support as a module with PCMCIA_DEBUG enabled. The symbol
soc_pcmcia_debug was not beeing exported.

Cc: <stable@kernel.org>
Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The existing code invokes the syscall with rubbish in r7,
due to what looks like an incorrect literal load idiom.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Commit f7cb1933 ("SLUB: Pass active
and inactive redzone flags instead of boolean to debug functions")
missed two instances of check_object(). This caused a lot of warnings
during 'slabinfo -v' finally leading to a crash:

  BUG ext4_xattr: Freepointer corrupt
  ...
  BUG buffer_head: Freepointer corrupt
  ...
  BUG ext4_alloc_context: Freepointer corrupt
  ...
  ...
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [<ffffffff810a291f>] file_sb_list_del+0x1c/0x35
  PGD 79d78067 PUD 79e67067 PMD 0
  Oops: 0002 [#1] SMP
  last sysfs file: /sys/kernel/slab/:t-0000192/validate

This patch fixes the problem by converting the two missed instances.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tero Roponen <tero.roponen@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

* '2.6.37-rc4-pvhvm-fixes' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
  xen: unplug the emulated devices at resume time
  xen: fix save/restore for PV on HVM guests with pirq remapping
  xen: resume the pv console for hvm guests too
  xen: fix MSI setup and teardown for PV on HVM guests
  xen: use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq

Merge branches 'upstream/core' and 'upstream/bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen

* 'upstream/core' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
  xen: allocate irq descs on any NUMA node
  xen: prevent crashes with non-HIGHMEM 32-bit kernels with largeish memory
  xen: use default_idle
  xen: clean up "extra" memory handling some more

* 'upstream/bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
  xen: x86/32: perform initial startup on initial_page_table
  xen: don't bother to stop other cpus on shutdown/reboot

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ASoC: omap: N810: Don't select CONFIG_OMAP_MUX but make it as dependency
  ALSA: hda: Use "alienware" model quirk for another SSID
  ASoC: WM8731: Fix incorrect mask for bypass path disable
  s6105-ipcam: fix compilation
  s6000-pcm: fix compilation
  s6000-i2s: fix compilation
  ASoC: Fix missing spin_unlock_irqrestore
  ALSA: Fix SNDCTL_DSP_RESET ioctl for OSS emulation
  ASoC: Add missing dev_set_drvdata in p1022_ds_probe
  ASoC: Add missing dev_set_drvdata in mpc8610_hpcd_probe
  ASoC: Remove unneeded !! operations while checking return value of nuc900_checkready
  ASoC: Fix compile error for nuc900-pcm.c
  ASoC: Fix prototype for nuc900_ac97_probe and nuc900_ac97_remove
  ASoC: Fix compile error for nuc900-ac97.c
  ALSA: hda: Use BIOS auto-parsing instead of existing model quirk for MEDION MD2

* 'linux-next' of git://git.infradead.org/ubi-2.6:
  UBI: fix corrupted PEB detection for NOR flash

* 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
  sh: se/7724: Remove FSI/B of GPIO init code
  sh: se/7724: Update clock framework of FSI clock to non-legacy
  sh: Assume new page cache pages have dirty dcache lines.
  sh: boards: mach-se: use IS_ERR() instead of NULL check
  sh: Add div6_reparent_clks to clock framework for FSI
  dma: shdma: add a MODULE_ALIAS() to allow module autoloading

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

* 'fbdev-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6:
  lxfb: Maintain video processor palette through suspend/resume
  video: da8xx: Register IRQ as last thing in driver probing.
  framebuffer: fix fbcmap.c kernel-doc warning

Implement asm/syscall.h for the MN10300 arch.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

My new shiny code for corrupted PEB detection has NOR specific bug.
We tread PEB as corrupted and preserve it, if

1. EC header is OK.
2. VID header is corrupted.
3. data area is not "all 0xFFs"

In case of NOR we have 'nor_erase_prepare()' quirk, which invalidates
the headers before erasing the PEB. And we invalidate first the VID
header, and then the EC header. So if a power cut happens after we have
invalidated the VID header, but before we have invalidated the EC
header, we end up with a PEB which satisfies the above 3 conditions,
and the scanning code will treat it as corrupted, and will print
scary warnings, wrongly.

This patch fixes the issue by firt invalidating the EC header, then
invalidating the VID header. In case of power cut inbetween, we still
just lose the EC header, and UBI can deal with this situation gracefully.

Thanks to Anatolij Gustschin <agust@denx.de> for tracking this down.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reported-by: Anatolij Gustschin <agust@denx.de>
Tested-by: Anatolij Gustschin <agust@denx.de>

se7724 board does not have FSI/B.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: length resolution should be reported units/mm
  HID: add support for F430 Force Feedback Wheel
  HID: egalax: Use kzalloc
  HID: Remove KERN_DEBUG from dbg_hid use

Manually fixed trivial conflict in drivers/hid/hid-input.c (due to
removal of KERN_DEBUG from dbg_hid use clashing with new keycode
interface switch)

Allocate irq descs on any NUMA node (we don't care) rather than
specifically node 0, which may not exist.

(At the moment NUMA is meaningless within a domain, so any info
the kernel has is just from an SRAT table we haven't suppressed/disabled.)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

If this is a non-HIGHMEM 32-bit kernel, then the page structures only go
up to the limit of addressable memory, even if more memory is physically
present.  Don't try to add that extra memory to the balloon.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

If a user manages to trigger an oops with fs set to KERNEL_DS, fs is not
otherwise reset before do_exit().  do_exit may later (via mm_release in
fork.c) do a put_user to a user-controlled address, potentially allowing
a user to leverage an oops into a controlled write into kernel memory.

This is only triggerable in the presence of another bug, but this
potentially turns a lot of DoS bugs into privilege escalations, so it's
worth fixing.  I have proof-of-concept code which uses this bug along
with CVE-2010-3849 to write a zero to an arbitrary kernel address, so
I've tested that this is not theoretical.

A more logical place to put this fix might be when we know an oops has
occurred, before we call do_exit(), but that would involve changing
every architecture, in multiple places.

Let's just stick it in do_exit instead.

[akpm@linux-foundation.org: update code comment]
Signed-off-by: Nelson Elhage <nelhage@ksplice.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

commit 62b61f61 ("ksm: memory hotremove migration only") caused the
following new lockdep warning.

  =======================================================
  [ INFO: possible circular locking dependency detected ]
  -------------------------------------------------------
  bash/1621 is trying to acquire lock:
   ((memory_chain).rwsem){.+.+.+}, at: [<ffffffff81079339>]
  __blocking_notifier_call_chain+0x69/0xc0

  but task is already holding lock:
   (ksm_thread_mutex){+.+.+.}, at: [<ffffffff8113a3aa>]
  ksm_memory_callback+0x3a/0xc0

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #1 (ksm_thread_mutex){+.+.+.}:
       [<ffffffff8108b70a>] lock_acquire+0xaa/0x140
       [<ffffffff81505d74>] __mutex_lock_common+0x44/0x3f0
       [<ffffffff81506228>] mutex_lock_nested+0x48/0x60
       [<ffffffff8113a3aa>] ksm_memory_callback+0x3a/0xc0
       [<ffffffff8150c21c>] notifier_call_chain+0x8c/0xe0
       [<ffffffff8107934e>] __blocking_notifier_call_chain+0x7e/0xc0
       [<ffffffff810793a6>] blocking_notifier_call_chain+0x16/0x20
       [<ffffffff813afbfb>] memory_notify+0x1b/0x20
       [<ffffffff81141b7c>] remove_memory+0x1cc/0x5f0
       [<ffffffff813af53d>] memory_block_change_state+0xfd/0x1a0
       [<ffffffff813afd62>] store_mem_state+0xe2/0xf0
       [<ffffffff813a0bb0>] sysdev_store+0x20/0x30
       [<ffffffff811bc116>] sysfs_write_file+0xe6/0x170
       [<ffffffff8114f398>] vfs_write+0xc8/0x190
       [<ffffffff8114fc14>] sys_write+0x54/0x90
       [<ffffffff810028b2>] system_call_fastpath+0x16/0x1b

  -> #0 ((memory_chain).rwsem){.+.+.+}:
       [<ffffffff8108b5ba>] __lock_acquire+0x155a/0x1600
       [<ffffffff8108b70a>] lock_acquire+0xaa/0x140
       [<ffffffff81506601>] down_read+0x51/0xa0
       [<ffffffff81079339>] __blocking_notifier_call_chain+0x69/0xc0
       [<ffffffff810793a6>] blocking_notifier_call_chain+0x16/0x20
       [<ffffffff813afbfb>] memory_notify+0x1b/0x20
       [<ffffffff81141f1e>] remove_memory+0x56e/0x5f0
       [<ffffffff813af53d>] memory_block_change_state+0xfd/0x1a0
       [<ffffffff813afd62>] store_mem_state+0xe2/0xf0
       [<ffffffff813a0bb0>] sysdev_store+0x20/0x30
       [<ffffffff811bc116>] sysfs_write_file+0xe6/0x170
       [<ffffffff8114f398>] vfs_write+0xc8/0x190
       [<ffffffff8114fc14>] sys_write+0x54/0x90
       [<ffffffff810028b2>] system_call_fastpath+0x16/0x1b

But it's a false positive.  Both memory_chain.rwsem and ksm_thread_mutex
have an outer lock (mem_hotplug_mutex).  So they cannot deadlock.

Thus, This patch annotate ksm_thread_mutex is not deadlock source.

[akpm@linux-foundation.org: update comment, from Hugh]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>