Commit 871af121 enabled 32bit PIO for
PATA piix but didn't for SATA.  There's no reason not to use 32bit PIO
on SATA piix.  Enable it.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

When sata_promise encounters an overrun or underrun error it
translates that to a libata AC_ERR_HSM, causing a hard reset.
Since over/under-runs were thought to be rare and transient,
this action seemed reasonable.

Unfortunately it turns out that the controller throws overrun
errors when e.g. hal polls a CD or DVD writer containing blank
media, causing long sequences of hard resets and retries before
EH finally gives up.

This patch updates sata_promise to classify over/under-runs as
AC_ERR_OTHER instead. This allows libata EH and upper layers to
retry or fail the operation as they see fit without the disruption
caused by repeated hard resets.

This fixes a problem using a DVD-RAM drive with sata_promise,
reported by Thomas Schorpp. I also tested it on a DVD-RW drive.
Signed-off-by: NMikael Pettersson <mikpe@it.uu.se>
Tested-by: Nthomas schorpp <thomas.schorpp@googlemail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Revert commit 2fbd07a5, as this commit
breaks an IBM platform with quad-core Xeon cpu's.

According to Suresh, this might be an IBM platform issue, as on other
Intel platforms with <= 8 logical cpu's, logical flat mode works fine
irespective of physical apic id values (inline with the xapic
architecture).

Revert this for now because of the IBM platform breakage.

Another version will be re-submitted after the complete analysis.
Signed-off-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: Ensure we force all busy extents in range to disk
  xfs: Don't flush stale inodes
  xfs: fix timestamp handling in xfs_setattr
  xfs: use DECLARE_EVENT_CLASS

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes:
  GFS2: Use MAX_LFS_FILESIZE for meta inode size
  GFS2: Fix gfs2_xattr_acl_chmod()
  GFS2: Fix locking bug in rename
  GFS2: Ensure uptodate inode size when using O_APPEND

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6:
  quota: Fix dquot_transfer for filesystems different from ext4

* 'agp-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/agp-2.6:
  agp/hp: fail gracefully if we don't find an IOC
  agp/hp: fixup hp agp after ACPI changes
  agp: correct missing cleanup on error in agp_add_bridge

* 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (45 commits)
  drm/nv04: Fix set_operation software method.
  drm/nouveau: initialise DMA tracking parameters earlier
  drm/nouveau: use dma.max rather than pushbuf size for checking GET validity
  drm/nv04: differentiate between nv04/nv05
  drm/nouveau: Fix null deref in nouveau_fence_emit due to deleted fence
  drm/nv50: prevent a possible ctxprog hang
  drm/nouveau: have ttm's fault handler called directly
  drm/nv50: restore correct cache1 get/put address on fifoctx load
  drm/nouveau: create function for "dealing" with gpu lockup
  drm/nouveau: remove unused nouveau_channel_idle() function
  drm/nouveau: fix handling of fbcon colours in 8bpp
  drm/nv04: Context switching fixes.
  drm/nouveau: Use the software object for fencing.
  drm/nouveau: Allocate a per-channel instance of NV_SW.
  drm/nv50: make the blocksize depend on vram size
  drm/nouveau: better alignment of bo sizes and use roundup instead of ALIGN
  drm/nouveau: Don't skip card take down on nv0x.
  drm/nouveau: Implement nv42-nv43 TV load detection.
  drm/nouveau: Clean up the nv17-nv4x load detection code a bit.
  drm/nv50: fix fillrect color
  ...

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  hwmon: Make PCI device ids constant
  hwmon: (coretemp) Fix TjMax for Atom N450/D410/D510 CPUs
  hwmon: (k10temp) Blacklist more family 10h processors
  hwmon: (asus_atk0110) Add debugfs interface
  hwmon: (asus_atk0110) Refactor interface probe code
  hwmon: (adt7462) Fix pin 28 monitoring

The list macros use LIST_POISON1 and LIST_POISON2 as undereferencable
pointers in order to trap erronous use of freed list_heads.  Unfortunately
userspace can arrange for those pointers to actually be dereferencable,
potentially turning an oops to an expolit.

To avoid this allow architectures (currently x86_64 only) to override
the default values for these pointers with truly-undereferencable values.
This is easy on x86_64 as the virtual address space is large and contains
areas that cannot be mapped.

Other 64-bit architectures will likely find similar unmapped ranges.

[ingo: switch to 0xdead000000000000 as the unmapped area]
[ingo: add comments, cleanup]
[jaswinder: eliminate sparse warnings]
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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

* 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6: (26 commits)
  OMAP2 clock: dynamically allocate CPUFreq frequency table
  OMAP clock/CPUFreq: add clk_exit_cpufreq_table()
  OMAP2xxx OPP: clean up comments in OPP data
  OMAP2xxx clock: clk2xxx.c doesn't compile if CPUFREQ is enabled
  OMAP1 clock: remove __initdata from struct clk_functions to prevent crash
  OMAP1 clock: Add missing clocks for OMAP 7xx
  OMAP clock: remove incorrect EXPORT_SYMBOL()s
  OMAP3 clock: Add capability to change rate of dpll4_m5_ck
  OMAP3 clock: McBSP 2, 3, 4 functional clock parent is PER_96M_FCLK, not CORE_96M_FCLK
  OMAP3: clock: add clockdomains for UART1 & 2
  OMAP2420 IO mapping: move IVA mapping virtual address out of vmalloc space
  OMAP2xxx IO mapping: mark DSP mappings as being 2420-only
  ARM: OMAP3: PM: Fix the Invalid CM_CLKSTCTRL reg access.
  OMAP2: remove duplicated #include
  omap3: EVM: Choose OMAP_PACKAGE_CBB
  omap3: Fix booting if package is uninitialized
  omap3: add missing parentheses
  omap3: add missing parentheses
  omap2/3: ZOOM: Correcting key mapping for few keys
  omap2/3: make serial_in_override() address the right uart port
  ...

Update the defconfig for the ASB2303 platform.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Access to the ASB2305's PCnet32 NIC doesn't work correctly because when
the NIC attempts to update the ring buffer flags by DMA, the change to RAM
crops up about 17uS after the interrupt line is asserted.  This is almost
certainly due to a bug in the PCI bridge FPGA on that board.

We can get around this by making dma_alloc_coherent() put the ring buffer
in the SRAM attached to the PCI bridge rather than in the SDRAM.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Insert PCI root bus resources for the MN10300-based ASB2305 development
kit motherboard.  This is required because the CPU's window onto the PCI
bus address space is considerably smaller than the CPU's full address
space and non-PCI devices lie outside of the PCI window that we might want
to access.

Without this patch, the PCI root bus uses the platform-level bus
resources, and these are then confined to the PCI window, thus making
platform_device_add() reject devices outside of this window.

We also add a reservation for the PCI SRAM region.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the generic pci_enable_resources() instead of the arch-specific code.

Unlike this arch-specific code, the generic version:

 - checks PCI_NUM_RESOURCES (11), not 6, resources
 - skips resources that have neither IORESOURCE_IO nor IORESOURCE_MEM set
 - skips ROM resources unless IORESOURCE_ROM_ENABLE is set
 - checks for resource collisions with "!r->parent"
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use KERN_ERR not KERN_ERROR in the ASB2305 platform code.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

asm/cpu never existed for mn10300; the files they are looking for are in
asm.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Wire up missing new system calls for MN10300.
Signed-off-by: NDavid Howells <dhowelsl@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

gcc 4.2.1 for MN10300 is more agressive than the older gcc in
reordering/moving other insns between an insn that sets flags and an insn
that uses those flags.  This leads to trouble with asm statements which
are missing an explicit "cc" clobber.  This patch adds the explicit "cc"
clobber to asm statements which do indeed clobber the condition flags.
Signed-off-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The gcc-4.2.1 based toolchain for MN10300 adds some new note sections
which need to be stripped from the binary image.  This patch takes care of
that.
Signed-off-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes a signal stack handling problem in the MN10300 arch.  When new
threads are cloned with CLONE_VM, they don't inherit the alternate signal
stack.  They do share the signal flags, though.  When deciding whether to
use an alternate stack, the arch code needs to check to make sure the task
struct contains a valid alternate stack.  This patch fixes the MN10300
arch by using the sas_ss_flags() test provided by sched.h rather than the
on_sig_stack() test which is insufficient by itself.
Signed-off-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

commit abd6633c ("pnp: add a shutdown
method to pnp drivers") adds shutdown method to bus driver blindly.  With
it, driver->shutdown is no longer valid.

Use pnp_driver->shutdown instead.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14889Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: NMalte Schröder <maltesch@gmx.de>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: David Hardeman <david@hardeman.nu>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: <stable@kernel.org>		[2.6.32.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A long time ago we regarded zero page as file_rss and vm_normal_page
doesn't return NULL.

But now, we reinstated ZERO_PAGE and vm_normal_page's implementation can
return NULL in case of zero page.  Also we don't count it with file_rss
any more.

Then, RSS and PSS can't be matched.  For consistency, Let's ignore zero
page in smaps_pte_range.
Signed-off-by: NMinchan Kim <minchan.kim@gmail.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: NMatt Mackall <mpm@selenic.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove comments about function short descriptions not allowed to be on
multiple lines (that was fixed/changed recently).

Add comments that function "section header:" names need to be unique per
function/struct/union/typedef/enum.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

menu: use proper 64 bit math

The new menu governor is incorrectly doing a 64 bit divide.  Compile
tested only
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix typos, grammos, spellos, hyphenation.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sz is in bytes, MAX_ORDER_NR_PAGES is in pages.
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Acked-by: NDavid Gibson <dwg@au1.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: <tomaz.mertelj@guest.arnes.si>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Previously enabled poll(2) support on one edge was never reconfigured when
sysfs polarity change was triggered from kernel, because 'struct device
*dev' shadowed an earlier definition.

Found by sparse, which I should've run much earlier.
Signed-off-by: NJani Nikula <ext-jani.1.nikula@nokia.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reported-by: NJosip Rodin <joy@entuzijast.net>
Cc: Joe Perches <joe@perches.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

JEDEC eMMC specification version 4.4 (MMCA 4.4) defines Extended CSD
structure versions up to 5.
Signed-off-by: NAdrian Hunter <adrian.hunter@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The main bug was that 'blk_cleanup_queue()' was called while the block
device could still be in use, for example, because the card was removed
while files were still open.

In addition, to be sure that 'mmc_request()' will get called for all new
requests (so it can error them out), the queue is emptied during cleanup.
This is done after the worker thread is stopped to avoid racing with it.

Finally, it is not a device error for this to be happening, so quiet the
(sometimes very many) error messages.
Signed-off-by: NAdrian Hunter <adrian.hunter@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If mmc_blk_set_blksize() fails mmc_blk_probe() the request queue and its
thread have been set up and they need to be shut down properly before
putting the disk.
Signed-off-by: NJarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: NAdrian Hunter <adrian.hunter@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When a card is removed before mmc_blk_probe() has called add_disk(), then
the minor field is uninitialized and has value 0.  This caused
mmc_blk_put() to always release devidx 0 even if 0 was still in use.  Then
the next mmc_blk_probe() used the first free idx of 0, which oopses in
sysfs, since it is used by another card.
Signed-off-by: NAnna Lemehova <EXT-Anna.Lemehova@nokia.com>
Signed-off-by: NAdrian Hunter <adrian.hunter@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Warning(drivers/base/power/main.c:453): No description found for parameter 'dev'
Warning(drivers/base/power/main.c:453): No description found for parameter 'cb'
Warning(drivers/base/power/main.c:719): No description found for parameter 'dev'
Warning(drivers/base/power/main.c:719): No description found for parameter 'state'
Warning(drivers/base/power/main.c:719): No description found for parameter 'cb'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit d899bf7b (procfs: provide stack information for threads) introduced
to show stack information in /proc/{pid}/status.  But it cause large
performance regression.  Unfortunately /proc/{pid}/status is used ps
command too and ps is one of most important component.  Because both to
take mmap_sem and page table walk are heavily operation.

If many process run, the ps performance is,

[before d899bf7b]

% perf stat ps >/dev/null

 Performance counter stats for 'ps':

     4090.435806  task-clock-msecs         #      0.032 CPUs
             229  context-switches         #      0.000 M/sec
               0  CPU-migrations           #      0.000 M/sec
             234  page-faults              #      0.000 M/sec
      8587565207  cycles                   #   2099.425 M/sec
      9866662403  instructions             #      1.149 IPC
      3789415411  cache-references         #    926.409 M/sec
        30419509  cache-misses             #      7.437 M/sec

   128.859521955  seconds time elapsed

[after d899bf7b]

% perf stat  ps  > /dev/null

 Performance counter stats for 'ps':

     4305.081146  task-clock-msecs         #      0.028 CPUs
             480  context-switches         #      0.000 M/sec
               2  CPU-migrations           #      0.000 M/sec
             237  page-faults              #      0.000 M/sec
      9021211334  cycles                   #   2095.480 M/sec
     10605887536  instructions             #      1.176 IPC
      3612650999  cache-references         #    839.160 M/sec
        23917502  cache-misses             #      5.556 M/sec

   152.277819582  seconds time elapsed

Thus, this patch revert it. Fortunately /proc/{pid}/task/{tid}/smaps
provide almost same information. we can use it.

Commit d899bf7b introduced two features:

 1) Add the annotattion of [thread stack: xxxx] mark to
    /proc/{pid}/task/{tid}/maps.
 2) Add StackUsage field to /proc/{pid}/status.

I only revert (2), because I haven't seen (1) cause regression.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

MIPS compressed kernels output a vmlinuz file in the top-level directory
(maybe others do).  Add vmlinuz to the list of files to ignore by git.
Signed-off-by: NFlorian Fainelli <ffainelli@freebox.fr>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When print-fatal-signals is enabled it's possible to dump any memory
reachable by the kernel to the log by simply jumping to that address from
user space.

Or crash the system if there's some hardware with read side effects.

The fatal signals handler will dump 16 bytes at the execution address,
which is fully controlled by ring 3.

In addition when something jumps to a unmapped address there will be up to
16 additional useless page faults, which might be potentially slow (and at
least is not very efficient)

Fortunately this option is off by default and only there on i386.

But fix it by checking for kernel addresses and also stopping when there's
a page fault.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The LTP cgroup test suite generates a "kernel BUG at kernel/cgroup.c:790!"
here in cgroup_diput():

                 /*
                  * if we're getting rid of the cgroup, refcount should ensure
                  * that there are no pidlists left.
                  */
                 BUG_ON(!list_empty(&cgrp->pidlists));

The cgroup pidlist rework in 2.6.32 generates the BUG_ON, which is caused
when pidlist_array_load() calls cgroup_pidlist_find():

(1) if a matching cgroup_pidlist is found, it down_write's the mutex of the
     pre-existing cgroup_pidlist, and increments its use_count.
(2) if no matching cgroup_pidlist is found, then a new one is allocated, it
     down_write's its mutex, and the use_count is set to 0.
(3) the matching, or new, cgroup_pidlist gets returned back to pidlist_array_load(),
     which increments its use_count -- regardless whether new or pre-existing --
     and up_write's the mutex.

So if a matching list is ever encountered by cgroup_pidlist_find() during
the life of a cgroup directory, it results in an inflated use_count value,
preventing it from ever getting released by cgroup_release_pid_array().
Then if the directory is subsequently removed, cgroup_diput() hits the
BUG_ON() when it finds that the directory's cgroup is still populated with
a pidlist.

The patch simply removes the use_count increment when a matching pidlist
is found by cgroup_pidlist_find(), because it gets bumped by the calling
pidlist_array_load() function while still protected by the list's mutex.
Signed-off-by: NDave Anderson <anderson@redhat.com>
Reviewed-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NBen Blum <bblum@andrew.cmu.edu>
Cc: Paul Menage <menage@google.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>