pidns: limit the nesting depth of pid namespaces

'struct pid' is a "variable sized struct" - a header with an array of
upids at the end.

The size of the array depends on a level (depth) of pid namespaces.  Now a
level of pidns is not limited, so 'struct pid' can be more than one page.

Looks reasonable, that it should be less than a page.  MAX_PIS_NS_LEVEL is
not calculated from PAGE_SIZE, because in this case it depends on
architectures, config options and it will be reduced, if someone adds a
new fields in struct pid or struct upid.

I suggest to set MAX_PIS_NS_LEVEL = 32, because it saves ability to expand
"struct pid" and it's more than enough for all known for me use-cases.
When someone finds a reasonable use case, we can add a config option or a
sysctl parameter.

In addition it will reduce the effect of another problem, when we have
many nested namespaces and the oldest one starts dying.
zap_pid_ns_processe will be called for each namespace and find_vpid will
be called for each process in a namespace.  find_vpid will be called
minimum max_level^2 / 2 times.  The reason of that is that when we found a
bit in pidmap, we can't determine this pidns is top for this process or it
isn't.

vpid is a heavy operation, so a fork bomb, which create many nested
namespace, can make a system inaccessible for a long time.  For example my
system becomes inaccessible for a few minutes with 4000 processes.

[akpm@linux-foundation.org: return -EINVAL in response to excessive nesting, not -ENOMEM]
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm, numa: avoid setting zone_reclaim_mode unless a node is sufficiently distant

Commit 957f822a0ab9 ("mm, numa: reclaim from all nodes within reclaim
distance") caused zone_reclaim_mode to be set for all systems where two
nodes are within RECLAIM_DISTANCE of each other.  This is the opposite
of what we actually want: zone_reclaim_mode should be set if two nodes
are sufficiently distant.

Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Julian Wollrath <jwollrath@web.de>
Tested-by: Julian Wollrath <jwollrath@web.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Patrik Kullman <patrik.kullman@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/rtc-imxdi.c: add missing spin lock initialization

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Roland Stigge <stigge@antcom.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Roland Stigge <stigge@antcom.de>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gen_init_cpio: avoid stack overflow when expanding

Fix possible overflow of the buffer used for expanding environment
variables when building file list.

In the extremely unlikely case of an attacker having control over the
environment variables visible to gen_init_cpio, control over the
contents of the file gen_init_cpio parses, and gen_init_cpio was built
without compiler hardening, the attacker can gain arbitrary execution
control via a stack buffer overflow.

  $ cat usr/crash.list
  file foo ${BIG}${BIG}${BIG}${BIG}${BIG}${BIG} 0755 0 0
  $ BIG=$(perl -e 'print "A" x 4096;') ./usr/gen_init_cpio usr/crash.list
  *** buffer overflow detected ***: ./usr/gen_init_cpio terminated

This also replaces the space-indenting with tabs.

Patch based on existing fix extracted from grsecurity.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: PaX Team <pageexec@freemail.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check

The compat ioctl for VIDEO_SET_SPU_PALETTE was missing an error check
while converting ioctl arguments.  This could lead to leaking kernel
stack contents into userspace.

Patch extracted from existing fix in grsecurity.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: PaX Team <pageexec@freemail.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
xtensa: allow multi-inclusion for uapi/unistd.h

Xtensa implements a method that allows to generate a arbitrary output
for each system call by defining the __SYSCALL(number, function, num_args).
This usually requires to include uapi/unistd.h twice. Instead of removing
the guard agains multiple inclusion entirely, allow to include unistd.h again
only if __SYSCALL is defined. Note that __SYSCALL gets always undefined at
the end of the file.

Signed-off-by: Chris Zankel <chris@zankel.net>
xtensa: use physical addresses for bus addresses

Define virt_to_bus and bus_to_virt as virt_to_phys, and phys_to_virt,
       respectively.

Signed-off-by: Chris Zankel <chris@zankel.net>
xtensa: reset windowbase/windowstart when cloning the VM

When we copy a user thread with CLONE_VM, we also have to reset
windowbase and windowstart to start a pristine stack frame. Otherwise,
overflows can happen using the address 0 as the stack pointer.
Also add a special case for vfork, which continues on the
parent stack until it calls execve. Because this could be a call8, we
need to spill the stack pointer of the previus frame (if still 'live' in
the register file).

Signed-off-by: Chris Zankel <chris@zankel.net>
xtensa: switch to generic kernel_thread()

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
xtensa: switch to generic kernel_execve()

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
xtensa: switch to generic sys_execve()

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
x86, mm: Undo incorrect revert in arch/x86/mm/init.c

Commit

    844ab6f9 x86, mm: Find_early_table_space based on ranges that are actually being mapped

added back some lines back wrongly that has been removed in commit

    7b16bbf97 Revert "x86/mm: Fix the size calculation of mapping tables"

remove them again.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/CAE9FiQW_vuaYQbmagVnxT2DGsYc=9tNeAbdBq53sYkitPOwxSQ@mail.gmail.com
Acked-by: Jacob Shin <jacob.shin@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Merge branch 'fixes_for_linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping

Pull CMA and DMA-mapping fixes from Marek Szyprowski:
 "This consists mainly of a set of one-liner fixes and cleanups for a
  few minor issues identified in both Contiguous Memory Allocator code
  and ARM DMA-mapping subsystem."

* 'fixes_for_linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  ARM: mm: Remove unused arm_vmregion priv field
  ARM: dma-mapping: fix build warning in __dma_alloc()
  ARM: dma-mapping: support debug_dma_mapping_error
  mm: cma: alloc_contig_range: return early for err path
  drivers: cma: Fix wrong CMA selected region size default value
  drivers: dma-coherent: Fix typo in dma_mmap_from_coherent documentation
  drivers: dma-contiguous: Don't redefine SZ_1M
Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm

Pull ARM fixes from Russell King:
 "A random collection of various fixes, mainly from Arnd and a few other
  people.  Not thing really stands out here."

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: drop experimental status for hotplug and Thumb2
  ARM: 7560/1: SMP_TWD: use DIV_ROUND_CLOSEST() for periodic mode
  ARM: 7559/1: smp: switch away from the idmap before updating init_mm.mm_count
  ARM: 7556/1: perf: fix updated event period in response to PERF_EVENT_IOC_PERIOD
  ARM: 7555/1: kexec: fix segment memory addresses check
  ARM: warnings in arch/arm/include/asm/uaccess.h
  ARM: binfmt_flat: unused variable 'persistent'
  ARM: be really quiet when building with 'make -s'
  ARM: pass -marm to gcc by default for both C and assembler
  ARM: Xen: fix initial build problems
  ARM: export default read_current_timer
  ARM: Fix another build warning in arch/arm/mm/alignment.c
  ARM: export set_irq_flags
  ARM: kprobes: make more tests conditional
Makefile: Documentation for external tool should be correct

If one includes documentation for an external tool, it should be
correct.  This is not:

1. Overriding the input to rngd should typically be neither
   necessary nor desired.  This is especially so since newer
   versions of rngd support a number of different *types* of sources.
2. The default kernel-exported device is called /dev/hwrng not
   /dev/hwrandom nor /dev/hw_random (both of which were used in the
   past; however, kernel and udev seem to have converged on
   /dev/hwrng.)

Overall it is better if the documentation for rngd is kept with rngd
rather than in a kernel Makefile.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Input: wacom - handle split-sensor devices with internal hubs

Like our other pen-and-touch products, the Cintiq 24HD touch needs data
to be shared between its two sensors to facilitate proximity-based palm
rejection.

Unlike other tablets that report sensor data through separate interfaces
of the same USB device, the Cintiq 24HD touch has separate USB devices
that are connected to an internal USB hub.

This patch makes it possible to designate the USB VID/PID of the other
device so that the two may share data.  To ensure we don't accidentally
link to a sensor from a physically separate device (if several have been
plugged in), we limit the search to siblings (i.e., devices directly
connected to the same hub).

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Input: wacom - add touch sensor support for Cintiq 24HD touch

Decode multitouch reports from the touch sensor of the Cintiq 24HD
touch.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ACPI: missing break

We handle NOTIFY_THROTTLING so don't then fall through to unsupported event.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'akpm' (Andrew's fixes)

Merge misc fixes from Andrew Morton:
 "18 total.  15 fixes and some updates to a device_cgroup patchset which
  bring it up to date with the version which I should have merged in the
  first place."

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (18 patches)
  fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check
  gen_init_cpio: avoid stack overflow when expanding
  drivers/rtc/rtc-imxdi.c: add missing spin lock initialization
  mm, numa: avoid setting zone_reclaim_mode unless a node is sufficiently distant
  pidns: limit the nesting depth of pid namespaces
  drivers/dma/dw_dmac: make driver's endianness configurable
  mm/mmu_notifier: allocate mmu_notifier in advance
  tools/testing/selftests/epoll/test_epoll.c: fix build
  UAPI: fix tools/vm/page-types.c
  mm/page_alloc.c:alloc_contig_range(): return early for err path
  rbtree: include linux/compiler.h for definition of __always_inline
  genalloc: stop crashing the system when destroying a pool
  backlight: ili9320: add missing SPI dependency
  device_cgroup: add proper checking when changing default behavior
  device_cgroup: stop using simple_strtoul()
  device_cgroup: rename deny_all to behavior
  cgroup: fix invalid rcu dereference
  mm: fix XFS oops due to dirty pages without buffers on s390
Merge branch 'drm-fixes-3.7' of git://people.freedesktop.org/~agd5f/linux into drm-fixes

Alex writes:
"Fixes pull request for radeon.  The main things here are
fixing a ATPX regression from the acpi rework, fixing some
fallout from the async VM work, and fixing some module options
that were broken in certain cases.  Other than that, mainly
just bug fixes."

* 'drm-fixes-3.7' of git://people.freedesktop.org/~agd5f/linux:
  drm/radeon: fix ATPX regression in acpi rework
  drm/radeon: fix ATPX function documentation
  drm/radeon: move the retry to gem_object_create
  drm/radeon: move size limits to gem_object_create.
  drm/radeon: use vzalloc for gart pages
  drm/radeon: fix and simplify pot argument checks v3
  drm/radeon: fix header size estimation in VM code
  drm/radeon: remove set_page check from VM code
  drm/radeon: fix si_set_page v2
  drm/radeon: fix cayman_vm_set_page v2
  drm/radeon: fix PFP sync in vm_flush
  drm/radeon: add error output if VM CS fails on cayman
  drm/radeon: give each backlight a unique id
  drm/radeon: fix sparse warning
  drm/radeon: add some new SI PCI ids