Preemption greatly raised the probability of certain types of race
conditions, so this commit adds an anti-heisenbug to greatly increase
the collision cross section, also known as the probability of occurrence.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

The current approach to grace-period initialization is vulnerable to
extremely low-probability races.  These races stem from the fact that
the old grace period is marked completed on the same traversal through
the rcu_node structure that is marking the start of the new grace period.
This means that some rcu_node structures will believe that the old grace
period is still in effect at the same time that other rcu_node structures
believe that the new grace period has already started.

These sorts of disagreements can result in too-short grace periods,
as shown in the following scenario:

1.	CPU 0 completes a grace period, but needs an additional
	grace period, so starts initializing one, initializing all
	the non-leaf rcu_node structures and the first leaf rcu_node
	structure.  Because CPU 0 is both completing the old grace
	period and starting a new one, it marks the completion of
	the old grace period and the start of the new grace period
	in a single traversal of the rcu_node structures.

	Therefore, CPUs corresponding to the first rcu_node structure
	can become aware that the prior grace period has completed, but
	CPUs corresponding to the other rcu_node structures will see
	this same prior grace period as still being in progress.

2.	CPU 1 passes through a quiescent state, and therefore informs
	the RCU core.  Because its leaf rcu_node structure has already
	been initialized, this CPU's quiescent state is applied to the
	new (and only partially initialized) grace period.

3.	CPU 1 enters an RCU read-side critical section and acquires
	a reference to data item A.  Note that this CPU believes that
	its critical section started after the beginning of the new
	grace period, and therefore will not block this new grace period.

4.	CPU 16 exits dyntick-idle mode.  Because it was in dyntick-idle
	mode, other CPUs informed the RCU core of its extended quiescent
	state for the past several grace periods.  This means that CPU 16
	is not yet aware that these past grace periods have ended.  Assume
	that CPU 16 corresponds to the second leaf rcu_node structure --
	which has not yet been made aware of the new grace period.

5.	CPU 16 removes data item A from its enclosing data structure
	and passes it to call_rcu(), which queues a callback in the
	RCU_NEXT_TAIL segment of the callback queue.

6.	CPU 16 enters the RCU core, possibly because it has taken a
	scheduling-clock interrupt, or alternatively because it has
	more than 10,000 callbacks queued.  It notes that the second
	most recent grace period has completed (recall that because it
	corresponds to the second as-yet-uninitialized rcu_node structure,
	it cannot yet become aware that the most recent grace period has
	completed), and therefore advances its callbacks.  The callback
	for data item A is therefore in the RCU_NEXT_READY_TAIL segment
	of the callback queue.

7.	CPU 0 completes initialization of the remaining leaf rcu_node
	structures for the new grace period, including the structure
	corresponding to CPU 16.

8.	CPU 16 again enters the RCU core, again, possibly because it has
	taken a scheduling-clock interrupt, or alternatively because
	it now has more than 10,000 callbacks queued.	It notes that
	the most recent grace period has ended, and therefore advances
	its callbacks.	The callback for data item A is therefore in
	the RCU_DONE_TAIL segment of the callback queue.

9.	All CPUs other than CPU 1 pass through quiescent states.  Because
	CPU 1 already passed through its quiescent state, the new grace
	period completes.  Note that CPU 1 is still in its RCU read-side
	critical section, still referencing data item A.

10.	Suppose that CPU 2 wais the last CPU to pass through a quiescent
	state for the new grace period, and suppose further that CPU 2
	did not have any callbacks queued, therefore not needing an
	additional grace period.  CPU 2 therefore traverses all of the
	rcu_node structures, marking the new grace period as completed,
	but does not initialize a new grace period.

11.	CPU 16 yet again enters the RCU core, yet again possibly because
	it has taken a scheduling-clock interrupt, or alternatively
	because it now has more than 10,000 callbacks queued.	It notes
	that the new grace period has ended, and therefore advances
	its callbacks.	The callback for data item A is therefore in
	the RCU_DONE_TAIL segment of the callback queue.  This means
	that this callback is now considered ready to be invoked.

12.	CPU 16 invokes the callback, freeing data item A while CPU 1
	is still referencing it.

This scenario represents a day-zero bug for TREE_RCU.  This commit
therefore ensures that the old grace period is marked completed in
all leaf rcu_node structures before a new grace period is marked
started in any of them.

That said, it would have been insanely difficult to force this race to
happen before the grace-period initialization process was preemptible.
Therefore, this commit is not a candidate for -stable.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Conflicts:

	kernel/rcutree.c

The module parameters blimit, qhimark, and qlomark (and more
recently, rcu_fanout_leaf) have permission masks of zero, so
that their values are not visible from sysfs.  This is unnecessary
and inconvenient to administrators who might like an easy way to
see what these values are on a running system.  This commit therefore
sets their permission masks to 0444, allowing them to be read but
not written.
Reported-by: NRusty Russell <rusty@ozlabs.org>
Reported-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Although almost everyone is well-served by the defaults, some uses of RCU
benefit from shorter grace periods, while others benefit more from the
greater efficiency provided by longer grace periods.  Situations requiring
a large number of grace periods to elapse (and wireshark startup has
been called out as an example of this) are helped by lower-latency
grace periods.  Furthermore, in some embedded applications, people are
willing to accept a small degradation in update efficiency (due to there
being more of the shorter grace-period operations) in order to gain the
lower latency.

In contrast, those few systems with thousands of CPUs need longer grace
periods because the CPU overhead of a grace period rises roughly
linearly with the number of CPUs.  Such systems normally do not make
much use of facilities that require large numbers of grace periods to
elapse, so this is a good tradeoff.

Therefore, this commit allows the durations to be controlled from sysfs.
There are two sysfs parameters, one named "jiffies_till_first_fqs" that
specifies the delay in jiffies from the end of grace-period initialization
until the first attempt to force quiescent states, and the other named
"jiffies_till_next_fqs" that specifies the delay (again in jiffies)
between subsequent attempts to force quiescent states.  They both default
to three jiffies, which is compatible with the old hard-coded behavior.

At some future time, it may be possible to automatically increase the
grace-period length with the number of CPUs, but we do not yet have
sufficient data to do a good job.  Preliminary data indicates that we
should add an addiitonal jiffy to each of the delays for every 200 CPUs
in the system, but more experimentation is needed.  For now, the number
of systems with more than 1,000 CPUs is small enough that this can be
relegated to boot-time hand tuning.
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Large systems running RCU_FAST_NO_HZ kernels see extreme memory
contention on the rcu_state structure's ->fqslock field.  This
can be avoided by disabling RCU_FAST_NO_HZ, either at compile time
or at boot time (via the nohz kernel boot parameter), but large
systems will no doubt become sensitive to energy consumption.
This commit therefore uses a combining-tree approach to spread the
memory contention across new cache lines in the leaf rcu_node structures.
This can be thought of as a tournament lock that has only a try-lock
acquisition primitive.

The effect on small systems is minimal, because such systems have
an rcu_node "tree" consisting of a single node.  In addition, this
functionality is not used on fastpaths.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Moving quiescent-state forcing into a kthread dispenses with the need
for the ->n_rp_need_fqs field, so this commit removes it.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

RCU quiescent-state forcing is currently carried out without preemption
points, which can result in excessive latency spikes on large systems
(many hundreds or thousands of CPUs).  This patch therefore inserts
a voluntary preemption point into force_qs_rnp(), which should greatly
reduce the magnitude of these spikes.
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Reported-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

As the first step towards allowing quiescent-state forcing to be
preemptible, this commit moves RCU quiescent-state forcing into the
same kthread that is now used to initialize and clean up after grace
periods.  This is yet another step towards keeping scheduling
latency down to a dull roar.

Updated to change from raw_spin_lock_irqsave() to raw_spin_lock_irq()
and to remove the now-unused rcu_state structure fields as suggested by
Peter Zijlstra.
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Reported-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The fields in the rcu_state structure that are protected by the
root rcu_node structure's ->lock can share a cache line with the
fields protected by ->onofflock.  This can result in excessive
memory contention on large systems, so this commit applies
____cacheline_internodealigned_in_smp to the ->onofflock field in
order to segregate them.
Signed-off-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NDimitri Sivanich <sivanich@sgi.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

In kernels built with CONFIG_RCU_FAST_NO_HZ=y, CPUs can accumulate a
large number of lazy callbacks, which as the name implies will be slow
to be invoked.  This can be a problem on small-memory systems, where the
default 6-second sleep for CPUs having only lazy RCU callbacks could well
be fatal.  This commit therefore installs an OOM hander that ensures that
every CPU with lazy callbacks has at least one non-lazy callback, in turn
ensuring timely advancement for these callbacks.

Updated to fix bug that disabled OOM killing, noted by Lai Jiangshan.

Updated to push the for_each_rcu_flavor() loop into rcu_oom_notify_cpu(),
thus reducing the number of IPIs, as suggested by Steven Rostedt.  Also
to make the for_each_online_cpu() loop be preemptible.  (Later, it might
be good to use smp_call_function(), as suggested by Peter Zijlstra.)
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NSasha Levin <levinsasha928@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Earlier versions of RCU invoked the RCU core from the CPU_DYING notifier
in order to note a quiescent state for the outgoing CPU.  Because the
CPU is marked "offline" during the execution of the CPU_DYING notifiers,
the RCU core had to tolerate being invoked from an offline CPU.  However,
commit b1420f1c (Make rcu_barrier() less disruptive) left only tracing
code in the CPU_DYING notifier, so the RCU core need no longer execute
on offline CPUs.  This commit therefore enforces this restriction.
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Then rcu_gp_kthread() function is too large and furthermore needs to
have the force_quiescent_state() code pulled in.  This commit therefore
breaks up rcu_gp_kthread() into rcu_gp_init() and rcu_gp_cleanup().
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

RCU grace-period cleanup is currently carried out with interrupts
disabled, which can result in excessive latency spikes on large systems
(many hundreds or thousands of CPUs).  This patch therefore makes the
RCU grace-period cleanup be preemptible, including voluntary preemption
points, which should eliminate those latency spikes.  Similar spikes from
forcing of quiescent states will be dealt with similarly by later patches.

Updated to replace uses of spin_lock_irqsave() with spin_lock_irq(), as
suggested by Peter Zijlstra.
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Reported-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

As a first step towards allowing grace-period cleanup to be preemptible,
this commit moves the RCU grace-period cleanup into the same kthread
that is now used to initialize grace periods.  This is needed to keep
scheduling latency down to a dull roar.

[ paulmck: Get rid of stray spin_lock_irqsave() calls. ]
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Reported-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

RCU grace-period initialization is currently carried out with interrupts
disabled, which can result in 200-microsecond latency spikes on systems
on which RCU has been configured for 4096 CPUs.  This patch therefore
makes the RCU grace-period initialization be preemptible, which should
eliminate those latency spikes.  Similar spikes from grace-period cleanup
and the forcing of quiescent states will be dealt with similarly by later
patches.
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Reported-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

The next step in reducing RCU's grace-period initialization latency on
large systems will make this initialization preemptible.  Unfortunately,
making the grace-period initialization subject to interrupts (let alone
preemption) exposes the following race on systems whose rcu_node tree
contains more than one node:

1.	CPU 31 starts initializing the grace period, including the
    	first leaf rcu_node structures, and is then preempted.

2.	CPU 0 refers to the first leaf rcu_node structure, and notes
    	that a new grace period has started.  It passes through a
    	quiescent state shortly thereafter, and informs the RCU core
    	of this rite of passage.

3.	CPU 0 enters an RCU read-side critical section, acquiring
    	a pointer to an RCU-protected data item.

4.	CPU 31 takes an interrupt whose handler removes the data item
	referenced by CPU 0 from the data structure, and registers an
	RCU callback in order to free it.

5.	CPU 31 resumes initializing the grace period, including its
    	own rcu_node structure.  In invokes rcu_start_gp_per_cpu(),
    	which advances all callbacks, including the one registered
    	in #4 above, to be handled by the current grace period.

6.	The remaining CPUs pass through quiescent states and inform
    	the RCU core, but CPU 0 remains in its RCU read-side critical
    	section, still referencing the now-removed data item.

7.	The grace period completes and all the callbacks are invoked,
    	including the one that frees the data item that CPU 0 is still
    	referencing.  Oops!!!

One way to avoid this race is to remove grace-period acceleration from
rcu_start_gp_per_cpu().  Now, the only reason for this acceleration was
to allow CPUs bringing RCU out of idle state to have their callbacks
invoked after only one grace period, rather than the two grace periods
that would otherwise be required.  But this acceleration does not
work when RCU grace-period initialization is moved to a kthread because
the CPU posting the callback is no longer necessarily the CPU that is
initializing the resulting grace period.

This commit therefore removes this now-pointless (and soon to be dangerous)
grace-period acceleration, thus avoiding the above race.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

As the first step towards allowing grace-period initialization to be
preemptible, this commit moves the RCU grace-period initialization
into its own kthread.  This is needed to keep large-system scheduling
latency at reasonable levels.

Also change raw_spin_lock_irqsave() to raw_spin_lock_irq() as suggested
by Peter Zijlstra in review comments.
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Reported-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Each grace period is supposed to have at least one callback waiting
for that grace period to complete.  However, if CONFIG_NO_HZ=n, an
extra callback-free grace period is no big problem -- it will chew up
a tiny bit of CPU time, but it will complete normally.  In contrast,
CONFIG_NO_HZ=y kernels have the potential for all the CPUs to go to
sleep indefinitely, in turn indefinitely delaying completion of the
callback-free grace period.  Given that nothing is waiting on this grace
period, this is also not a problem.

That is, unless RCU CPU stall warnings are also enabled, as they are
in recent kernels.  In this case, if a CPU wakes up after at least one
minute of inactivity, an RCU CPU stall warning will result.  The reason
that no one noticed until quite recently is that most systems have enough
OS noise that they will never remain absolutely idle for a full minute.
But there are some embedded systems with cut-down userspace configurations
that consistently get into this situation.

All this begs the question of exactly how a callback-free grace period
gets started in the first place.  This can happen due to the fact that
CPUs do not necessarily agree on which grace period is in progress.
If a CPU still believes that the grace period that just completed is
still ongoing, it will believe that it has callbacks that need to wait for
another grace period, never mind the fact that the grace period that they
were waiting for just completed.  This CPU can therefore erroneously
decide to start a new grace period.  Note that this can happen in
TREE_RCU and TREE_PREEMPT_RCU even on a single-CPU system:  Deadlock
considerations mean that the CPU that detected the end of the grace
period is not necessarily officially informed of this fact for some time.

Once this CPU notices that the earlier grace period completed, it will
invoke its callbacks.  It then won't have any callbacks left.  If no
other CPU has any callbacks, we now have a callback-free grace period.

This commit therefore makes CPUs check more carefully before starting a
new grace period.  This new check relies on an array of tail pointers
into each CPU's list of callbacks.  If the CPU is up to date on which
grace periods have completed, it checks to see if any callbacks follow
the RCU_DONE_TAIL segment, otherwise it checks to see if any callbacks
follow the RCU_WAIT_TAIL segment.  The reason that this works is that
the RCU_WAIT_TAIL segment will be promoted to the RCU_DONE_TAIL segment
as soon as the CPU is officially notified that the old grace period
has ended.

This change is to cpu_needs_another_gp(), which is called in a number
of places.  The only one that really matters is in rcu_start_gp(), where
the root rcu_node structure's ->lock is held, which prevents any
other CPU from starting or completing a grace period, so that the
comparison that determines whether the CPU is missing the completion
of a grace period is stable.
Reported-by: NBecky Bruce <bgillbruce@gmail.com>
Reported-by: NSubodh Nijsure <snijsure@grid-net.com>
Reported-by: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Walmsley <paul@pwsan.com>  # OMAP3730, OMAP4430
Cc: stable@vger.kernel.org

Tracepoints declare a static inline trace_*_rcuidle variant of the trace
function, to support safely generating trace events from the idle loop.
Module code never actually uses that variant of trace functions, because
modules don't run code that needs tracing with RCU idled.  However, the
declaration of those otherwise unused functions causes the module to
reference rcu_idle_exit and rcu_idle_enter, which RCU does not export to
modules.

To avoid this, don't generate trace_*_rcuidle functions for tracepoints
declared in module code.

Link: http://lkml.kernel.org/r/20120905062306.GA14756@leafReported-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Pull DMA-mapping fixes from Marek Szyprowski:
 "Another set of fixes for ARM dma-mapping subsystem.

  Commit e9da6e99 replaced custom consistent buffer remapping code
  with generic vmalloc areas.  It however introduced some regressions
  caused by limited support for allocations in atomic context.  This
  series contains fixes for those regressions.

  For some subplatforms the default, pre-allocated pool for atomic
  allocations turned out to be too small, so a function for setting its
  size has been added.

  Another set of patches adds support for atomic allocations to
  IOMMU-aware DMA-mapping implementation.

  The last part of this pull request contains two fixes for Contiguous
  Memory Allocator, which relax too strict requirements."

* 'fixes-for-3.6' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  ARM: dma-mapping: IOMMU allocates pages from atomic_pool with GFP_ATOMIC
  ARM: dma-mapping: Introduce __atomic_get_pages() for __iommu_get_pages()
  ARM: dma-mapping: Refactor out to introduce __in_atomic_pool
  ARM: dma-mapping: atomic_pool with struct page **pages
  ARM: Kirkwood: increase atomic coherent pool size
  ARM: DMA-Mapping: print warning when atomic coherent allocation fails
  ARM: DMA-Mapping: add function for setting coherent pool size from platform code
  ARM: relax conditions required for enabling Contiguous Memory Allocator
  mm: cma: fix alignment requirements for contiguous regions

Pull input subsystem updates from Dmitry Torokhov.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: wacom - add support for EMR on Cintiq 24HD touch
  Input: i8042 - add Gigabyte T1005 series netbooks to noloop table
  Input: imx_keypad - reset the hardware before enabling
  Input: edt-ft5x06 - fix build error when compiling wthout CONFIG_DEBUG_FS

Pull HID updates from Jiri Kosina:
 "It contains a fix for Eaton Ellipse MAX UPS from Alan Stern,
  performance improvement (not processing debug data if noone is
  interested), by Henrik Rydberg, and allowing tpkbd-driven devices to
  work even with generic driver in a crippled mode, by Andres Freund."

* 'upstream-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: tpkbd: work even if the new Lenovo Keyboard driver is not configured
  HID: Only dump input if someone is listening
  HID: add NOGET quirk for Eaton Ellipse MAX UPS

c1dcad2d added a new driver configured by
HID_LENOVO_TPKBD but made the hid_have_special_driver entry non-optional which
lead to a recognized but non-working device if the new driver wasn't
configured (which is the correct default).
Signed-off-by: NAndres Freund <andres@anarazel.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Merge tag 'stable/for-linus-3.6-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen bug-fixes from Konrad Rzeszutek Wilk:
 * Fix for TLB flushing introduced in v3.6
 * Fix Xen-SWIOTLB not using proper DMA mask - device had 64bit but
   in a 32-bit kernel we need to allocate for coherent pages from a
   32-bit pool.
 * When trying to re-use P2M nodes we had a one-off error and triggered
   a BUG_ON check with specific CONFIG_ option.
 * When doing FLR in Xen-PCI-backend we would first do FLR then save the
   PCI configuration space. We needed to do it the other way around.

* tag 'stable/for-linus-3.6-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/pciback: Fix proper FLR steps.
  xen: Use correct masking in xen_swiotlb_alloc_coherent.
  xen: fix logical error in tlb flushing
  xen/p2m: Fix one-off error in checking the P2M tree directory.

Pull PCI updates from Bjorn Helgaas:
 "Power management
    - PCI/PM: Enable D3/D3cold by default for most devices
    - PCI/PM: Keep parent bridge active when probing device
    - PCI/PM: Fix config reg access for D3cold and bridge suspending
    - PCI/PM: Add ABI document for sysfs file d3cold_allowed
  Core
    - PCI: Don't print anything while decoding is disabled"

* tag '3.6-pci-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Don't print anything while decoding is disabled
  PCI/PM: Add ABI document for sysfs file d3cold_allowed
  PCI/PM: Fix config reg access for D3cold and bridge suspending
  PCI/PM: Keep parent bridge active when probing device
  PCI/PM: Enable D3/D3cold by default for most devices

Pull ARM SoC bug fixes from Olof Johansson:
 "Mostly Renesas and Atmel bugfixes this time, targeting boot and build
  problems.  A couple of patches for gemini and kirkwood as well.  On a
  whole nothing very controversial."

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: gemini: fix the gemini build
  ARM: shmobile: armadillo800eva: enable rw rootfs mount
  ARM: Kirkwood: Fix 'SZ_1M' undeclared here for db88f6281-bp-setup.c
  ARM: shmobile: mackerel: fixup usb module order
  ARM: shmobile: armadillo800eva: fixup: sound card detection order
  ARM: shmobile: marzen: fixup smsc911x id for regulator
  ARM: at91/feature-removal-schedule: delay at91_mci removal
  ARM: mach-shmobile: armadillo800eva: Enable power button as wakeup source
  ARM: mach-shmobile: armadillo800eva: Fix GPIO buttons descriptions
  ARM: at91/dts: remove partial parameter in at91sam9g25ek.dts
  ARM: at91/clock: fix PLLA overclock warning
  ARM: at91: fix rtc-at91sam9 irq issue due to sparse irq support
  ARM: at91: fix system timer irq issue due to sparse irq support
  ARM: shmobile: sh73a0: fixup RELOC_BASE of intca_irq_pins_desc

Pull a hwmon fix from Guenter Roeck:
 "One patch, fixing DIV_ROUND_CLOSEST to support negative dividends.

  While the changes are not in the drivers/hwmon directory, the problem
  primarily affects hwmon drivers, and it makes sense to push the patch
  through the hwmon tree."

* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  linux/kernel.h: Fix DIV_ROUND_CLOSEST to support negative dividends

Pull kbuild fixes from Michal Marek:
 "These are two fixes that should go into 3.6.  The link-vmlinux.sh one
  is obvious.

  The other one fixes make firmware_install with certain configurations,
  where a file in the toplevel firmware tree gets installed first, and
  $(INSTALL_FW_PATH)/$$(dir <file>) results in /lib/firmware/./, which
  confuses make 3.82 for some reason."

* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  firmware: fix directory creation rule matching with make 3.82
  link-vmlinux.sh: Fix stray "echo" in error message

Trivially triggerable, found by trinity:

  kernel BUG at mm/mempolicy.c:2546!
  Process trinity-child2 (pid: 23988, threadinfo ffff88010197e000, task ffff88007821a670)
  Call Trace:
    show_numa_map+0xd5/0x450
    show_pid_numa_map+0x13/0x20
    traverse+0xf2/0x230
    seq_read+0x34b/0x3e0
    vfs_read+0xac/0x180
    sys_pread64+0xa2/0xc0
    system_call_fastpath+0x1a/0x1f
  RIP: mpol_to_str+0x156/0x360

Cc: stable@vger.kernel.org
Signed-off-by: NDave Jones <davej@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we do FLR and save PCI config we did it in the wrong order.
The end result was that if a PCI device was unbind from
its driver, then binded to xen-pciback, and then back to its
driver we would get:

> lspci -s 04:00.0
04:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
13:42:12 # 4 :~/
> echo "0000:04:00.0" > /sys/bus/pci/drivers/pciback/unbind
> modprobe e1000e
e1000e: Intel(R) PRO/1000 Network Driver - 2.0.0-k
e1000e: Copyright(c) 1999 - 2012 Intel Corporation.
e1000e 0000:04:00.0: Disabling ASPM L0s L1
e1000e 0000:04:00.0: enabling device (0000 -> 0002)
xen: registering gsi 48 triggering 0 polarity 1
Already setup the GSI :48
e1000e 0000:04:00.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
e1000e: probe of 0000:04:00.0 failed with error -2

This fixes it by first saving the PCI configuration space, then
doing the FLR.
Reported-by: NRen, Yongjie <yongjie.ren@intel.com>
Reported-and-Tested-by: NTobias Geiger <tobias.geiger@vido.info>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: stable@vger.kernel.org

Pull MMC fixes from Chris Ball:
 - a firmware bug on several Samsung MoviNAND eMMC models causes
   permanent corruption on the device when secure erase and secure trim
   requests are made, so we disable those requests on these eMMC devices.
 - atmel-mci: fix a hang with some SD cards by waiting for not-busy flag.
 - dw_mmc: low-power mode breaks SDIO interrupts; fix PIO error handling;
   fix handling of error interrupts.
 - mxs-mmc: fix deadlocks; fix compile error due to dma.h arch change.
 - omap: fix broken PIO mode causing memory corruption.
 - sdhci-esdhc: fix card detection.

* tag 'mmc-fixes-for-3.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc:
  mmc: omap: fix broken PIO mode
  mmc: card: Skip secure erase on MoviNAND; causes unrecoverable corruption.
  mmc: dw_mmc: Disable low power mode if SDIO interrupts are used
  mmc: dw_mmc: fix error handling in PIO mode
  mmc: dw_mmc: correct mishandling error interrupt
  mmc: dw_mmc: amend using error interrupt status
  mmc: atmel-mci: not busy flag has also to be used for read operations
  mmc: sdhci-esdhc: break out early if clock is 0
  mmc: mxs-mmc: fix deadlock caused by recursion loop
  mmc: mxs-mmc: fix deadlock in SDIO IRQ case
  mmc: bfin_sdh: fix dma_desc_array build error

Fix the following compile error on UML.

  arch/um/os-Linux/time.c: In function 'deliver_alarm':
  arch/um/os-Linux/time.c:117:3: error: too few arguments to function 'alarm_handler'
  arch/um/os-Linux/internal.h:1:6: note: declared here

The error was introduced by commit d3c1cfcd ("um: pass siginfo to guest
process") in 3.6-rc1.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Martin Pärtel <martin.partel@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Allocate a structure not a pointer to it !
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull powerpc fixes from Benjamin Herrenschmidt:
 "Here are a few fixes for 3.6 that were piling up while I was away or
  busy (I was mostly MIA a week or two before San Diego).

  Some fixes from Anton fixing up issues with our relatively new DSCR
  control feature, and a few other fixes that are either regressions or
  bugs nasty enough to warrant not waiting."

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc: Don't use __put_user() in patch_instruction
  powerpc: Make sure IPI handlers see data written by IPI senders
  powerpc: Restore correct DSCR in context switch
  powerpc: Fix DSCR inheritance in copy_thread()
  powerpc: Keep thread.dscr and thread.dscr_inherit in sync
  powerpc: Update DSCR on all CPUs when writing sysfs dscr_default
  powerpc/powernv: Always go into nap mode when CPU is offline
  powerpc: Give hypervisor decrementer interrupts their own handler
  powerpc/vphn: Fix arch_update_cpu_topology() return value

Pull GPIO fixes from Linus Walleij:
 "These are some GPIO regression fixes for v3.6:
   - Erroneous debug message from of_get_named_gpio_flags()
   - Make sure the MC9S08DZ60 GPIO driver depend on I2C being compiled
     in (not module) or allmodconfig breaks.
   - Check return value from irq_alloc_descs() in the Emma Mobile GPIO
     driver.
   - Assign the owner field for the rdc321x driver so the module won't
     be removed if it has active GPIOs."

* tag 'gpio-fixes-for-v3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio: rdc321x: Prevent removal of modules exporting active GPIOs
  gpio: em: Fix checking return value of irq_alloc_descs
  gpio: mc9s08dz60: Fix build error if I2C=m
  gpio: Fix debug message in of_get_named_gpio_flags()

Pull sound fixes from Takashi Iwai:
 "There are nothing scaring, contains only small fixes for HD-audio and
  USB-audio:
   - EPSS regression fix and GPIO fix for HD-audio IDT codecs
   - A series of USB-audio regression fixes that are found since 3.5
     kernel"

* tag 'sound-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: snd-usb: fix cross-interface streaming devices
  ALSA: snd-usb: fix calls to next_packet_size
  ALSA: snd-usb: restore delay information
  ALSA: snd-usb: use list_for_each_safe for endpoint resources
  ALSA: snd-usb: Fix URB cancellation at stream start
  ALSA: hda - Don't trust codec EPSS bit for IDT 92HD83xx & co
  ALSA: hda - Avoid unnecessary parameter read for EPSS
  ALSA: hda - Do not set GPIOs for speakers on IDT if there are no speakers

Pull fbdev fixes from Florian Tobias Schandinat:
 - a fix by Paul Cercueil to prevent a possible buffer overflow
 - a fix by Bruno Prémont to prevent a rare sleep in invalid context
 - a fix by Julia Lawall for a double free in auo_k190x
 - a fix by Dan Carpenter to prevent a division by zero in mb862xxfb
 - a regression fix by Tomi Valkeinen for the SDI output in OMAP
 - a fix by Grazvydas Ignotas to fix the console colors in OMAP

* tag 'fbdev-fixes-for-3.6-1' of git://github.com/schandinat/linux-2.6:
  OMAPFB: fix framebuffer console colors
  OMAPDSS: Fix SDI PLL locking
  video: mb862xxfb: prevent divide by zero bug
  drivers/video/auo_k190x.c: drop kfree of devm_kzalloc's data
  fbcon: Fix bit_putcs() call to kmalloc(s, GFP_KERNEL)
  fbcon: prevent possible buffer overflow.

Pull ubi fix from Artem Bityutskiy:
 "A single small fix for memory deallocation: we allocated memory using
  'kmem_cache_alloc()' but were freeing it using 'kfree()' in some
  cases.  Now we fix this by using 'kmem_cache_free()' instead."

* tag 'upstream-3.6-rc5' of git://git.infradead.org/linux-ubi:
  UBI: fix a horrible memory deallocation bug

Commit 644595f8 ("compat: Handle COMPAT_USE_64BIT_TIME in
net/socket.c") introduced a bug where the helper functions to take
either a 64-bit or compat time[spec|val] got the arguments in the wrong
order, passing the kernel stack pointer off as a user pointer (and vice
versa).

Because of the user address range check, that in turn then causes an
EFAULT due to the user pointer range checking failing for the kernel
address.  Incorrectly resuling in a failed system call for 32-bit
processes with a 64-bit kernel.

On odder architectures like HP-PA (with separate user/kernel address
spaces), it can be used read kernel memory.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>