Using a program like the following:

	#include <stdlib.h>
	#include <unistd.h>
	#include <sys/types.h>
	#include <sys/wait.h>

	int main() {
		id_t id;
		siginfo_t infop;
		pid_t res;

		id = fork();
		if (id == 0) { sleep(1); exit(0); }
		kill(id, SIGSTOP);
		alarm(1);
		waitid(P_PID, id, &infop, WCONTINUED);
		return 0;
	}

to call waitid() on a stopped process results in access to the child task's
credentials without the RCU read lock being held - which may be replaced in the
meantime - eliciting the following warning:

	===================================================
	[ INFO: suspicious rcu_dereference_check() usage. ]
	---------------------------------------------------
	kernel/exit.c:1460 invoked rcu_dereference_check() without protection!

	other info that might help us debug this:

	rcu_scheduler_active = 1, debug_locks = 1
	2 locks held by waitid02/22252:
	 #0:  (tasklist_lock){.?.?..}, at: [<ffffffff81061ce5>] do_wait+0xc5/0x310
	 #1:  (&(&sighand->siglock)->rlock){-.-...}, at: [<ffffffff810611da>]
	wait_consider_task+0x19a/0xbe0

	stack backtrace:
	Pid: 22252, comm: waitid02 Not tainted 2.6.35-323cd+ #3
	Call Trace:
	 [<ffffffff81095da4>] lockdep_rcu_dereference+0xa4/0xc0
	 [<ffffffff81061b31>] wait_consider_task+0xaf1/0xbe0
	 [<ffffffff81061d15>] do_wait+0xf5/0x310
	 [<ffffffff810620b6>] sys_waitid+0x86/0x1f0
	 [<ffffffff8105fce0>] ? child_wait_callback+0x0/0x70
	 [<ffffffff81003282>] system_call_fastpath+0x16/0x1b

This is fixed by holding the RCU read lock in wait_task_continued() to ensure
that the task's current credentials aren't destroyed between us reading the
cred pointer and us reading the UID from those credentials.

Furthermore, protect wait_task_stopped() in the same way.

We don't need to keep holding the RCU read lock once we've read the UID from
the credentials as holding the RCU read lock doesn't stop the target task from
changing its creds under us - so the credentials may be outdated immediately
after we've read the pointer, lock or no lock.
Signed-off-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:

arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type

This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to.  This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel().  A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().

do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.

Further kernel_execve() and sys_execve() need to be changed to match.

This has been test built on x86_64, frv, arm and mips.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NRalf Baechle <ralf@linux-mips.org>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
  gcc-4.6: ACPI: fix unused but set variables in ACPI
  ACPI thermal: make procfs I/F depend on CONFIG_ACPI_PROCFS
  ACPI video: make procfs I/F depend on CONFIG_ACPI_PROCFS
  ACPI processor: remove deprecated ACPI procfs I/F
  ACPI power_resource: remove unused procfs I/F
  ACPI: remove deprecated ACPI procfs I/F
  ACPI: introduce drivers/acpi/sysfs.c
  ACPI: introduce module parameter acpi.aml_debug_output
  ACPI: introduce drivers/acpi/debugfs.c
  ACPI, APEI, ERST debug support
  ACPI, APEI, Manage GHES as platform devices
  ACPI, APEI, Rename CPER and GHES severity constants
  ACPI, APEI, Fix a typo of error path of apei_resources_request
  ACPI / ACPICA: Fix reference counting problems with GPE handlers
  ACPI: Add the check of ADR flag in course of finding ACPI handle for PCI device
  ACPI / Sleep: Drop acpi_suspend_finish()
  ACPI / Sleep: Consolidate suspend and hibernation routines
  ACPI / Wakeup: Simplify enabling of wakeup devices
  ACPI / Sleep: Rework enabling wakeup devices
  ACPI / Sleep: Free NVS copy if suspending of devices fails

Fixed up totally buggered "ACPI: fix unused but set variables in ACPI"
patch that doesn't even compile in the merge.

Thanks to Sedat Dilek <sedat.dilek@googlemail.com> for noticing the
breakage before I even pulled.  And a big "Grrr.." at Len for not even
bothering to compile the tree before asking me to pull.

* git://git.infradead.org/iommu-2.6:
  intel-iommu: Fix 32-bit build warning with __cmpxchg()
  intr-remap: allow disabling source id checking

* git://git.infradead.org/mtd-2.6:
  mtd/nand_ids: Fix buswidth
  mtd/m25p80: fix test for end of loop
  mtd/m25p80: retlen is never NULL
  MIPS: Fix gen_nand probe structures contents
  gen_nand: Test if nr_chips field is valid
  BFIN: Fix gen_nand probe structures contents
  nand/denali: move all hardware initialization work to denali_hw_init
  nand/denali: Add a page check in denali_read_page & denali_read_page_raw
  nand/denali: use cpu_relax() while waiting for hardware interrupt
  nand/denali: change read_status function method
  nand/denali: Fixed check patch warnings
  ARM: Fix gen_nand probe structures contents
  mtd/nand_base: fix kernel-doc warnings & typos
  nand/denali: use dev_xx debug function to replace nand_dbg_print and some printk
  nand/denali: Fixed handle ECC error bugs
  nand/denali: use iowrite32() to replace denali_write32()
  nand/denali: Fixed probe function bugs

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: don't validate CROSS_COMPILE needlessly
  arch/tile: export only COMMAND_LINE_SIZE to userspace.
  arch/tile: rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN
  arch/tile: Rename the hweight() implementations to __arch_hweight()
  arch/tile: extend syscall ABI to set r1 on return as well.
  arch/tile: Various cleanups.
  arch/tile: support backtracing on TILE-Gx
  arch/tile: Fix a couple of issues with the COMPAT code for TILE-Gx.
  arch/tile: Use separate, better minsec values for clocksource and sched_clock.
  arch/tile: correct a bug in freeing bootmem by VA for the optional second initrd.
  arch: tile: mm: pgtable.c: Removed duplicated #include
  arch: tile: kernel/proc.c Removed duplicated #include
  Add fanotify syscalls to <asm-generic/unistd.h>.
  arch/tile: support new kunmap_atomic() naming convention.
  tile: remove unused ISA_DMA_THRESHOLD define

Conflicts in arch/tile/configs/tile_defconfig (pick the mainline version
with the reduced defconfig).

With this change, the arch/tile Makefile will only check for a valid
combination of CROSS_COMPILE vs "uname -m" for a few common targets
that are typically the ones we get wrong (vmlinux, all, and modules).
The change handles the case of an empty "make" goal like "make all".
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>

This commit makes the stack guard page somewhat less visible to user
space. It does this by:

 - not showing the guard page in /proc/<pid>/maps

   It looks like lvm-tools will actually read /proc/self/maps to figure
   out where all its mappings are, and effectively do a specialized
   "mlockall()" in user space.  By not showing the guard page as part of
   the mapping (by just adding PAGE_SIZE to the start for grows-up
   pages), lvm-tools ends up not being aware of it.

 - by also teaching the _real_ mlock() functionality not to try to lock
   the guard page.

   That would just expand the mapping down to create a new guard page,
   so there really is no point in trying to lock it in place.

It would perhaps be nice to show the guard page specially in
/proc/<pid>/maps (or at least mark grow-down segments some way), but
let's not open ourselves up to more breakage by user space from programs
that depends on the exact deails of the 'maps' file.

Special thanks to Henrique de Moraes Holschuh for diving into lvm-tools
source code to see what was going on with the whole new warning.

Reported-and-tested-by: François Valenduc <francois.valenduc@tvcablenet.be
Reported-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ALSA: sound/usb/format: silence uninitialized variable warnings
  MAINTAINERS: Add Ian Lartey as comaintaner for Wolfson devices
  MAINTAINERS: Make Wolfson entry also cover CODEC drivers
  ASoC: Only tweak WM8994 chip configuration on devices up to rev D
  ASoC: Optimise DSP performance for WM8994
  ALSA: hda - Fix dynamic ADC change working again
  ALSA: hda - Restrict PCM parameters per ELD information over HDMI
  sound: oss: sh_dac_audio.c removed duplicated #include

* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6:
  intel_idle: recognize Lincroft Atom Processor
  intel_idle: no longer EXPERIMENTAL
  intel_idle: disable module support
  intel_idle: add support for Westmere-EX
  intel_idle: delete power_policy modparam, and choose substate functions
  intel_idle: delete substates DEBUG modparam

This fixes a failure in "make headers_check" for tile.
I hadn't realized this file was exported to userspace by default.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

See commit a6eb9fe1.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

Gcc complains that ret might be used uninitialized:

sound/usb/format.c: In function ‘snd_usb_parse_audio_format’:
sound/usb/format.c:354: warning: ‘ret’ may be used uninitialized in this function
sound/usb/format.c:354: note: ‘ret’ was declared here
sound/usb/format.c:414: warning: ‘ret’ may be used uninitialized in this function
sound/usb/format.c:414: note: ‘ret’ was declared here

I suppose it could be uninitialized if there is ever a UAC_VERSION_3
released. Anyway this patch is worthwhile if only to silence the gcc
warning.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Acked-by: NDaniel Mack <daniel@caiaq.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Conflicts:
	drivers/acpi/debug.c
Signed-off-by: NLen Brown <len.brown@intel.com>

Some minor improvements in error handling, but overall it was mostly dead
code.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLen Brown <len.brown@intel.com>

Mark the ACPI thermal procfs I/F deprecated, because /sys/class/thermal/
is already available and has been working for years w/o any problem.

The ACPI thermal procfs I/F will be removed in 2.6.37.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Mark ACPI video driver procfs I/F deprecated, including:
/proc/acpi/video/*/info
/proc/acpi/video/*/DOS
/proc/acpi/video/*/ROM
/proc/acpi/video/*/POST
/proc/acpi/video/*/POST_info
/proc/acpi/video/*/*/info
/proc/acpi/video/*/*/state
/proc/acpi/video/*/*/EDID
and
/proc/acpi/video/*/*/brightness, because
1. we already have the sysfs I/F /sysclass/backlight/ as the replacement
of /proc/acpi/video/*/*/brightness.
2. the other procfs I/F is not useful for userspace.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Remove deprecated ACPI processor procfs I/F, including:
/proc/acpi/processor/CPUX/power
/proc/acpi/processor/CPUX/limit
/proc/acpi/processor/CPUX/info

/proc/acpi/processor/CPUX/throttling still exists,
as we don't have sysfs I/F available for now.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Remove unused ACPI power procfs I/F.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Rmove deprecated ACPI procfs I/F, including
/proc/acpi/debug_layer
/proc/acpi/debug_level
/proc/acpi/info
/proc/acpi/dsdt
/proc/acpi/fadt
/proc/acpi/sleep

because the sysfs I/F is already available
and has been working well for years.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Introduce drivers/acpi/sysfs.c.

code for ACPI sysfs I/F, including
#ifdef ACPI_DEBUG
/sys/module/acpi/parameters/debug_layer
/sys/module/acpi/parameters/debug_level
/sys/module/acpi/parameters/trace_method_name
/sys/module/acpi/parameters/trace_debug_layer
/sys/module/acpi/parameters/trace_debug_level
/sys/module/acpi/parameters/trace_state
#endif
/sys/module/acpi/parameters/acpica_version
/sys/firmware/acpi/tables/
/sys/firmware/acpi/interrupts/
is moved to this file.

No function change in this patch.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Introduce module parameter acpi.aml_debug_output.

With acpi.aml_debug_output set, we can get AML debug object output
(Store (AAA, Debug)), even with CONFIG_ACPI_DEBUG cleared.

Together with the runtime custom method mechanism,
we can debug AML code problems without rebuilding the kernel.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Introduce drivers/acpi/debugfs.c.

Code for ACPI debugfs I/F,
i.e. /sys/kernel/debug/acpi/custom_method,
is moved to this file.

And make ACPI debugfs always built in,
even if CONFIG_ACPI_DEBUG is cleared.

BTW:this adds about 400bytes code to ACPI, when
CONFIG_ACPI_DEBUG is cleared.

[uaccess.h build fix from Andrew Morton <akpm@linux-foundation.org>]
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

This patch adds debugging/testing support to ERST. A misc device is
implemented to export raw ERST read/write/clear etc operations to user
space. With this patch, we can add ERST testing support to
linuxfirmwarekit ISO (linuxfirmwarekit.org) to verify the kernel
support and the firmware implementation.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

* git://git.kernel.org/pub/scm/linux/kernel/git/sam/cleanup:
  defconfig reduction
  kbuild: drop unifdef-y support
  archs: replace unifdef-y with header-y
  include: replace unifdef-y with header-y

Fix fusion missing kernel-doc:

  Warning(drivers/message/fusion/mptbase.c:649): No description found for parameter 'func_name'
  Warning(drivers/message/fusion/mptbase.c:8010): No description found for parameter 'cb_idx'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix parameter name in kernel-doc notation (causes a warning).
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix comment begin notation not to look like kernel-doc
since it's not.  Removes kernel-doc warnings.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove leading /** from non-kernel-doc function comments to prevent
kernel-doc warnings.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move SCSI parameters from kernel-parameters.txt to their own text file.

This continues a trend of moving non-core parameters out of
kernel-parameters.txt.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging: (22 commits)
  hwmon: (via-cputemp) Remove bogus "SHOW" global variable
  hwmon: jc42 depends on I2C
  hwmon: (pc87427) Add a maintainer
  hwmon: (pc87427) Move sysfs file removal to a separate function
  hwmon: (pc87427) Add temperature monitoring support
  hwmon: (pc87427) Add support for the second logical device
  hwmon: (pc87427) Add support for manual fan speed control
  hwmon: (pc87427) Minor style cleanups
  hwmon: (pc87427) Handle disabled fan inputs properly
  hwmon: (w83627ehf) Add support for W83667HG-B
  hwmon: (w83627ehf) Driver cleanup
  hwmon: Add driver for SMSC EMC2103 temperature monitor and fan controller
  hwmon: Remove in[0-*]_fault from sysfs-interface
  hwmon: Add 4 current alarm/beep attributes to sysfs-interface
  hwmon: Add 3 critical limit attributes to sysfs-interface
  hwmon: (asc7621) Clean up and improve detect function
  hwmon: (it87) Export labels for internal sensors
  hwmon: (lm75) Add suspend/resume feature
  hwmon: (emc1403) Add power support
  hwmon: (ltc4245) Expose all GPIO pins as analog voltages
  ...