As I was adding code that affects all archs, I started testing function
tracer against PPC64 and found that it currently locks up with 3.4
kernel. I figured it was due to tracing a function that shouldn't be, so
I went through the following process to bisect to find the culprit:

 cat /debug/tracing/available_filter_functions > t
 num=`wc -l t`
 sed -ne "1,${num}p" t > t1
 let num=num+1
 sed -ne "${num},$p" t > t2
 cat t1 > /debug/tracing/set_ftrace_filter
 echo function /debug/tracing/current_tracer
 <failed? bisect t1, if not bisect t2>

It finally came down to this function: restore_interrupts()

I'm not sure why this locks up the system. It just seems to prevent
scheduling from occurring. Interrupts seem to still work, as I can ping
the box. But all user processes freeze.

When restore_interrupts() is not traced, function tracing works fine.

Cc: stable@kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patches tries to fix a couple of Section mismatch warnings like
following one:

WARNING: arch/powerpc/kernel/built-in.o(.text+0x2923c): Section mismatch
in reference from the function .prom_query_opal() to the
function .init.text:.call_prom()
The function .prom_query_opal() references
the function __init .call_prom().
This is often because .prom_query_opal lacks a __init
annotation or the annotation of .call_prom is wrong.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

In entry_64.S version of ret_from_except_lite, you'll notice that
in the !preempt case, after we've checked MSR_PR we test for any
TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work
or not. However, in the preempt case, we do a convoluted trick to
test SIGPENDING only if PR was set and always test NEED_RESCHED ...
but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So
that means that with preempt, we completely fail to test for things
like single step, syscall tracing, etc...

This should be fixed as the following path:

 - Test PR. If not set, go to resume_kernel, else continue.

 - If go resume_kernel, to do that original do_work.

 - If else, then always test for _TIF_USER_WORK_MASK to decide to do
that original user_work, else restore directly.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

chroma_defconfig currently gives me this with gcc 4.6:
  arch/powerpc/mm/numa.c:638:13: error: 'dm' may be used uninitialized in this function [-Werror=uninitialized]

It's a bogus warning/error since of_get_drconf_memory() only writes it
anyway.
Signed-off-by: Michael Neuling <mikey@neuling.org>
cc: <stable@kernel.org> [v3.3+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

If the kernel is big enough (eg. allyesconfig), the linker may need to
switch TOCs when calling from the BPF JIT code out to the external
helpers (skb_copy_bits() & bpf_internal_load_pointer_neg_helper()).

In order to do that we need to leave space after the bl for the linker
to insert a reload of our TOC pointer.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Pull hwmon changes from Guenter Roeck:
 "Just e-mail address updates"

* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: Update my e-mail address
  hwmon: (applesmc) correct email address for Jesper Juhl

Pull watchdog fixes from Wim Van Sebroeck:
 "This fixes:
   - the WDIOC_GETSTATUS return value
   - the unregister of all NMI events on exit
   - the loading of the iTCO_wdt driver after the conversion to the
     lpc_ich mfd model."

* git://www.linux-watchdog.org/linux-watchdog:
  watchdog: core: fix WDIOC_GETSTATUS return value
  watchdog: hpwdt: Unregister NMI events on exit.
  watchdog: iTCO_wdt: add platform driver module alias

Pull UDF fixes from Jan Kara:
 "Make UDF more robust in presence of corrupted filesystem"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  udf: Fortify loading of sparing table
  udf: Avoid run away loop when partition table length is corrupted
  udf: Use 'ret' instead of abusing 'i' in udf_load_logicalvol()

Pull ubi/ubifs fixes from Artem Bityutskiy:
 "Fix the debugfs regression - we never enable it because incorrect
  'IS_ENABLED()' macro usage: should be 'IS_ENABLED(CONFIG_DEBUG_FS)',
  but we had 'IS_ENABLED(DEBUG_FS)'.  Also fix incorrect assertion."

* tag 'upstream-3.5-rc5' of git://git.infradead.org/linux-ubifs:
  UBI: correct usage of IS_ENABLED()
  UBIFS: correct usage of IS_ENABLED()
  UBIFS: fix assertion

In commit 7a879824 we added
a wrapper for the WDIOC_GETSTATUS ioctl call. The code results
however in a different behaviour: it returns an error if the
driver doesn't support the status operation. This is not
according to the API that says that when we don't support
the status operation, that we just should return a 0 value.
Only when the device isn't there anymore, we should return an
error.
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This patch is to unregister for NMI events upon exit. Also we are now
making the default setting for allow_kdump enabled.
Signed-off-by: Thomas Mingarelli <thomas.mingarelli@hp.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

The recent conversion of iTCO_wdt resulted in the driver no longer
getting loaded automatically, since it no longer has a
MODULE_DEVICE_TABLE() included. As the lpc_ich driver now creates a
platform device, auto-loading can easily be done by having a respective
module alias in place.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Aaron Sierra <asierra@xes-inc.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Pull drm fixes from Dave Airlie:
 "Nearly all intel, one missing license header in nouveau, nothing
  majorly earth shattering."

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  Revert "drm/i915: allow PCH PWM override on IVB"
  drm/nouveau: add license header to prime.
  drm/i915: Fix eDP blank screen after S3 resume on HP desktops
  drm/i915: rip out the PM_IIR WARN

Pull SuperH fixes from Paul Mundt.

* tag 'sh-for-linus' of git://github.com/pmundt/linux-sh:
  sh: Convert sh_clk_mstp32_register to sh_clk_mstp_register
  sh: kfr2r09: fix compile breakage

Pull networking update from David Miller:

 1) Pairing and deadlock fixes in bluetooth from Johan Hedberg.

 2) Add device IDs for AR3011 and AR3012 bluetooth chips.  From
    Giancarlo Formicuccia and Marek Vasut.

 3) Fix wireless regulatory deadlock, from Eliad Peller.

 4) Fix full TX ring panic in bnx2x driver, from Eric Dumazet.

 5) Revert the two commits that added skb_orphan_try(), it causes
    erratic bonding behavior with UDP clients and the gains it used to
    give are mostly no longer happening due to how BQL works.  From Eric
    Dumazet.

 6) It took two tries, but Thomas Graf fixed a problem wherein we
    registered ipv6 routing procfs files before their backend data were
    initialized properly.

 7) Fix max GSO size setting in be2net, from Sarveshwar Bandi.

 8) PHY device id mask is wrong for KSZ9021 and KS8001 chips, fix from
    Jason Wang.

 9) Fix use of stale SKB data pointer after skb_linearize() call in
    batman-adv, from Antonio Quartulli.

10) Fix memory leak in IXGBE due to missing __GFP_COMP, from Alexander
    Duyck.

11) Fix probing of Gobi devices in qmi_wwan usbnet driver, from Bjørn
    Mork.

12) Fix suspend/resume and open failure handling in usbnet from Ming
    Lei.

13) Attempt to fix device r8169 hangs for certain chips, from Francois
    Romieu.

14) Fix advancement of RX dirty pointer in some situations in sh_eth
    driver, from Yoshihiro Shimoda.

15) Attempt to fix restart of IPV6 routing table dumps when there is an
    intervening table update.  From Eric Dumazet.

16) Respect security_inet_conn_request() return value in ipv6 TCP.  From
    Neal Cardwell.

17) Add another iPAD device ID to ipheth driver, from Davide Gerhard.

18) Fix access to freed SKB in l2tp_eth_dev_xmit(), and fix l2tp lockdep
    splats, from Eric Dumazet.

19) Make sure all bridge devices, regardless of whether they were
    created via netlink or ioctls, have their rtnetlink ops hooked up.
    From Thomas Graf and Stephen Hemminger.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (81 commits)
  9p: fix min_t() casting in p9pdu_vwritef()
  can: flexcan: use be32_to_cpup to handle the value of dt entry
  xen/netfront: teardown the device before unregistering it.
  bridge: Assign rtnl_link_ops to bridge devices created via ioctl (v2)
  vhost: use USER_DS in vhost_worker thread
  ixgbe: Do not pad FCoE frames as this can cause issues with FCoE DDP
  net: l2tp_eth: use LLTX to avoid LOCKDEP splats
  mac802154: add missed braces
  net: l2tp_eth: fix l2tp_eth_dev_xmit race
  net/mlx4_en: Release QP range in free_resources
  net/mlx4: Use single completion vector after NOP failure
  net/mlx4_en: Set correct port parameters during device initialization
  ipheth: add support for iPad
  caif-hsi: Add missing return in error path
  caif-hsi: Bugfix - Piggyback'ed embedded CAIF frame lost
  caif: Clear shutdown mask to zero at reconnect.
  tcp: heed result of security_inet_conn_request() in tcp_v6_conn_request()
  ipv6: fib: fix fib dump restart
  batman-adv: fix race condition in TT full-table replacement
  batman-adv: only drop packets of known wifi clients
  ...

Add sanity checks when loading sparing table from disk to avoid accessing
unallocated memory or writing to it.
Signed-off-by: Jan Kara <jack@suse.cz>

Check provided length of partition table so that (possibly maliciously)
corrupted partition table cannot cause accessing data beyond current buffer.
Signed-off-by: Jan Kara <jack@suse.cz>

Signed-off-by: Jan Kara <jack@suse.cz>

sh_clk_mstp32_register is deprecated. This convert to sh_clk_mstp_register.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Fix compile breakage caused by

commit aa82f9fc
Author: Paul Mundt <lethal@linux-sh.org>

    sh: kfr2r09 evt2irq migration.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Marc Kleine-Budde says:

====================
here's a patch intended for v3.5, targeting net/master. Hui Wang has
found and fixed an endianness problem in the device tree handling in
the flexcan driver.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

I don't think we're actually likely to hit this limit but if we do
then the comparison should be done as size_t.  The original code
is equivalent to:
        len = strlen(sptr) % USHRT_MAX;
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull USB fixes from Greg Kroah-Hartman:
 "Here are some small USB gadget bugfixes, and a few new USB device ids
  added to some drivers for the 3.5-rc5 release.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'usb-3.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: CP210x Add 10 Device IDs
  USB: option: Add USB ID for Novatel Ovation MC551
  usb: phy: Fix Kconfig dependency for Phy drivers
  usb-storage: revert commit afff07e6 (Add 090c:1000 to unusal-devs)
  SCSI & usb-storage: add try_rc_10_first flag
  usb: musb: host: release dma channels if no active io
  usb: gadget: lpc32xx_udc: fix build error with debugfs enabled
  usb: otg: twl6030-usb: Fix twl writes
  USB: option: add id for Cellient MEN-200
  usb: dwc3: fix giveback of queued request in ep_dequeue
  usb: gadget: Complete fsl qe/udc driver conversion

Pull sound fixes from Takashi Iwai:
 "Here you find quite a few changes for HD-audio and a copule of quirk
  additions for USB-audio.  All reasonably small and/or trivial."

* tag 'sound-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda - Fix power-map regression for HP dv6 & co
  ALSA: hda - Initialize caches at codec reconfiguration
  ALSA: hda - Fix memory leaks at module unload
  ALSA: hda - Fix memory leaks in Realtek & Conexant codec parsers
  ALSA: hda - Add Realtek ALC280 codec support
  ALSA: hda - Remove obsoleted CONFIG_SND_HDA_ENABLE_REALTEK_QUIRKS
  ASoC: wm8994: remove duplicate code
  ALSA: usb-audio: add BOSS GT-100 support
  ALSA: HDA: Add inverted internal mic quirk for Lenovo S205
  ALSA: hda - Fix ALC272X codec detection
  ALSA: snd_usb_audio: ignore ctrl errors on QuickCam Pro for Notebooks
  ALSA: snd_usb_audio: ignore ctrl errors on QuickCam E3500

Pull a m68knommu fix from Greg Ungerer:
 "It contains a single fix for breakage using the Freescale FEC eth
  driver on ColdFire CPUs."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68knommu: define a local devm_clk_get() function

Pull MMC fixes from Chris Ball:

 - omap_hsmmc: Using AUTO_CMD12 (enabled by default in 3.5-rc1) has
   been found to cause data corruption on the BeagleBoard, but no
   other OMAP boards so far.  Revert the patch until there's a root
   cause explanation that makes sense, at which point we might
   decide to use a blacklist or whitelist.

 - mmc_block: Fix incorrect data timeouts for the case of multiblock
   (ACMD22) writes for block-addressed cards.

* tag 'mmc-fixes-for-3.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc:
  Revert "mmc: omap_hsmmc: Enable Auto CMD12"
  mmc: block: fix the data timeout issue with ACMD22

Pull clk common framework fixes from Mike Turquette:
 "This contains three NULL pointer fixes and two device regression
  fixups.

  Two NULL pointer dereferences were in the common clk core due to lack
  of sanity checking and the third NPD was in the mxs-specific clock
  code due to incorrect use of __initdata.

  The device regressions were the result of improper data: a wrong
  string name for matching DT data broke the SPEAr ethernet controller
  and another string matching problem in the mxs clock data resulted in
  a broken MMC controller."

* tag 'clk-fixes-for-linus' of git://git.linaro.org/people/mturquette/linux:
  clk: mxs: fix clock lookup after freeing init memory
  clk: mxs: fix ref_io clock definition
  clk: Check parent for NULL in clk_change_rate
  clk: Allow late cache allocation for clk->parents
  clk: SPEAr600: Fix ethernet clock name for DT based probing

This script lacks an executable bit.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Daniel writes:
"Two tiny patches and one revert:
- Kill a bogus error message introduced in 3.4, further Bspec reading
  indicates that this is how the hw is supposed to work.
- Reorder one backlight register restore, fixing broken backlight on some
  machines after resume.
- Revert a hack from Jesse for ivb backlight control - it breaks the
  backlight controls on my shiny new ivb laptop."

* 'drm-intel-fixes' of git://people.freedesktop.org/~danvet/drm-intel:
  Revert "drm/i915: allow PCH PWM override on IVB"
  drm/i915: Fix eDP blank screen after S3 resume on HP desktops
  drm/i915: rip out the PM_IIR WARN

This reverts commit f82cfb6b.

This breaks the backlight controls on my IVB asus zenbook with an eDP
panel.

I guess the right fix would be to read this bit and use either the pch
or the cpu register to frob the backlight values. But that is stuff
for -next.

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Commit "e9b4cf20 UBI: fix debugfs-less systems support" fixed one
regression but introduced a different regression - the debugfs is now always
compiled out. Root cause: IS_ENABLED() arguments should be used with the
CONFIG_* prefix.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

Commit "818039c7 UBIFS: fix debugfs-less systems support" fixed one
regression but introduced a different regression - the debugfs is now always
compiled out. Root cause: IS_ENABLED() arguments should be used with the
CONFIG_* prefix.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

The freescale arm i.MX series platform can support this driver, and
usually the arm cpu works in the little endian mode by default, while
device tree entry value is stored in big endian format, we should use
be32_to_cpup() to handle them, after modification, it can work well
both on the le cpu and be cpu.

Cc: stable <stable@vger.kernel.org> # v3.2+
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Hui Wang <jason77.wang@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Just forgot this when I posted it, and yes I'm the only person
to have changed the file since.
Signed-off-by: Dave Airlie <airlied@redhat.com>

Fixes:
[   15.470311] WARNING: at /local/scratch/ianc/devel/kernels/linux/fs/sysfs/file.c:498 sysfs_attr_ns+0x95/0xa0()
[   15.470326] sysfs: kobject eth0 without dirent
[   15.470333] Modules linked in:
[   15.470342] Pid: 12, comm: xenwatch Not tainted 3.4.0-x86_32p-xenU #93
and
[    9.150554] BUG: unable to handle kernel paging request at 2b359000
[    9.150577] IP: [<c1279561>] linkwatch_do_dev+0x81/0xc0
[    9.150592] *pdpt = 000000002c3c9027 *pde = 0000000000000000
[    9.150604] Oops: 0002 [#1] SMP
[    9.150613] Modules linked in:

This is http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=675190Reported-by: George Shuklin <george.shuklin@gmail.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Tested-by: William Dauchy <wdauchy@gmail.com>
Cc: stable@kernel.org
Cc: 675190@bugs.debian.org
Signed-off-by: David S. Miller <davem@davemloft.net>

This ensures that bridges created with brctl(8) or ioctl(2) directly
also carry IFLA_LINKINFO when dumped over netlink. This also allows
to create a bridge with ioctl(2) and delete it with RTM_DELLINK.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

On some architectures address spaces are set up in a way that this is
not necessary to work properly but on some others (like s390) it is.
Make sure we operate on the user address space to allow copy_xxx_user()
from the vhost_worker() thread by setting it explicitly before calling
use_mm() and revert it after unuse_mm().
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

FCoE target mode was experiencing issues due to the fact that we were
sending up data frames that were padded to 60 bytes after the DDP logic had
already stripped the frame down to 52 or 56 depending on the use of VLANs.
This was resulting in the FCoE DDP logic having issues since it thought the
frame still had data in it due to the padding.

To resolve this, adding code so that we do not pad FCoE frames prior to
handling them to the stack.

CC: <stable@vger.kernel.org>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Denys Fedoryshchenko reported a LOCKDEP issue with l2tp code.

[ 8683.927442] ======================================================
[ 8683.927555] [ INFO: possible circular locking dependency detected ]
[ 8683.927672] 3.4.1-build-0061 #14 Not tainted
[ 8683.927782] -------------------------------------------------------
[ 8683.927895] swapper/0/0 is trying to acquire lock:
[ 8683.928007]  (slock-AF_INET){+.-...}, at: [<e0fc73ec>]
l2tp_xmit_skb+0x173/0x47e [l2tp_core]
[ 8683.928121]
[ 8683.928121] but task is already holding lock:
[ 8683.928121]  (_xmit_ETHER#2){+.-...}, at: [<c02f062d>]
sch_direct_xmit+0x36/0x119
[ 8683.928121]
[ 8683.928121] which lock already depends on the new lock.
[ 8683.928121]
[ 8683.928121]
[ 8683.928121] the existing dependency chain (in reverse order) is:
[ 8683.928121]
[ 8683.928121] -> #1 (_xmit_ETHER#2){+.-...}:
[ 8683.928121]        [<c015a561>] lock_acquire+0x71/0x85
[ 8683.928121]        [<c034da2d>] _raw_spin_lock+0x33/0x40
[ 8683.928121]        [<c0304e0c>] ip_send_reply+0xf2/0x1ce
[ 8683.928121]        [<c0317dbc>] tcp_v4_send_reset+0x153/0x16f
[ 8683.928121]        [<c0317f4a>] tcp_v4_do_rcv+0x172/0x194
[ 8683.928121]        [<c031929b>] tcp_v4_rcv+0x387/0x5a0
[ 8683.928121]        [<c03001d0>] ip_local_deliver_finish+0x13a/0x1e9
[ 8683.928121]        [<c0300645>] NF_HOOK.clone.11+0x46/0x4d
[ 8683.928121]        [<c030075b>] ip_local_deliver+0x41/0x45
[ 8683.928121]        [<c03005dd>] ip_rcv_finish+0x31a/0x33c
[ 8683.928121]        [<c0300645>] NF_HOOK.clone.11+0x46/0x4d
[ 8683.928121]        [<c0300960>] ip_rcv+0x201/0x23d
[ 8683.928121]        [<c02de91b>] __netif_receive_skb+0x329/0x378
[ 8683.928121]        [<c02deae8>] netif_receive_skb+0x4e/0x7d
[ 8683.928121]        [<e08d5ef3>] rtl8139_poll+0x243/0x33d [8139too]
[ 8683.928121]        [<c02df103>] net_rx_action+0x90/0x15d
[ 8683.928121]        [<c012b2b5>] __do_softirq+0x7b/0x118
[ 8683.928121]
[ 8683.928121] -> #0 (slock-AF_INET){+.-...}:
[ 8683.928121]        [<c0159f1b>] __lock_acquire+0x9a3/0xc27
[ 8683.928121]        [<c015a561>] lock_acquire+0x71/0x85
[ 8683.928121]        [<c034da2d>] _raw_spin_lock+0x33/0x40
[ 8683.928121]        [<e0fc73ec>] l2tp_xmit_skb+0x173/0x47e
[l2tp_core]
[ 8683.928121]        [<e0fe31fb>] l2tp_eth_dev_xmit+0x1a/0x2f
[l2tp_eth]
[ 8683.928121]        [<c02e01e7>] dev_hard_start_xmit+0x333/0x3f2
[ 8683.928121]        [<c02f064c>] sch_direct_xmit+0x55/0x119
[ 8683.928121]        [<c02e0528>] dev_queue_xmit+0x282/0x418
[ 8683.928121]        [<c031f4fb>] NF_HOOK.clone.19+0x45/0x4c
[ 8683.928121]        [<c031f524>] arp_xmit+0x22/0x24
[ 8683.928121]        [<c031f567>] arp_send+0x41/0x48
[ 8683.928121]        [<c031fa7d>] arp_process+0x289/0x491
[ 8683.928121]        [<c031f4fb>] NF_HOOK.clone.19+0x45/0x4c
[ 8683.928121]        [<c031f7a0>] arp_rcv+0xb1/0xc3
[ 8683.928121]        [<c02de91b>] __netif_receive_skb+0x329/0x378
[ 8683.928121]        [<c02de9d3>] process_backlog+0x69/0x130
[ 8683.928121]        [<c02df103>] net_rx_action+0x90/0x15d
[ 8683.928121]        [<c012b2b5>] __do_softirq+0x7b/0x118
[ 8683.928121]
[ 8683.928121] other info that might help us debug this:
[ 8683.928121]
[ 8683.928121]  Possible unsafe locking scenario:
[ 8683.928121]
[ 8683.928121]        CPU0                    CPU1
[ 8683.928121]        ----                    ----
[ 8683.928121]   lock(_xmit_ETHER#2);
[ 8683.928121]                                lock(slock-AF_INET);
[ 8683.928121]                                lock(_xmit_ETHER#2);
[ 8683.928121]   lock(slock-AF_INET);
[ 8683.928121]
[ 8683.928121]  *** DEADLOCK ***
[ 8683.928121]
[ 8683.928121] 3 locks held by swapper/0/0:
[ 8683.928121]  #0:  (rcu_read_lock){.+.+..}, at: [<c02dbc10>]
rcu_lock_acquire+0x0/0x30
[ 8683.928121]  #1:  (rcu_read_lock_bh){.+....}, at: [<c02dbc10>]
rcu_lock_acquire+0x0/0x30
[ 8683.928121]  #2:  (_xmit_ETHER#2){+.-...}, at: [<c02f062d>]
sch_direct_xmit+0x36/0x119
[ 8683.928121]
[ 8683.928121] stack backtrace:
[ 8683.928121] Pid: 0, comm: swapper/0 Not tainted 3.4.1-build-0061 #14
[ 8683.928121] Call Trace:
[ 8683.928121]  [<c034bdd2>] ? printk+0x18/0x1a
[ 8683.928121]  [<c0158904>] print_circular_bug+0x1ac/0x1b6
[ 8683.928121]  [<c0159f1b>] __lock_acquire+0x9a3/0xc27
[ 8683.928121]  [<c015a561>] lock_acquire+0x71/0x85
[ 8683.928121]  [<e0fc73ec>] ? l2tp_xmit_skb+0x173/0x47e [l2tp_core]
[ 8683.928121]  [<c034da2d>] _raw_spin_lock+0x33/0x40
[ 8683.928121]  [<e0fc73ec>] ? l2tp_xmit_skb+0x173/0x47e [l2tp_core]
[ 8683.928121]  [<e0fc73ec>] l2tp_xmit_skb+0x173/0x47e [l2tp_core]
[ 8683.928121]  [<e0fe31fb>] l2tp_eth_dev_xmit+0x1a/0x2f [l2tp_eth]
[ 8683.928121]  [<c02e01e7>] dev_hard_start_xmit+0x333/0x3f2
[ 8683.928121]  [<c02f064c>] sch_direct_xmit+0x55/0x119
[ 8683.928121]  [<c02e0528>] dev_queue_xmit+0x282/0x418
[ 8683.928121]  [<c02e02a6>] ? dev_hard_start_xmit+0x3f2/0x3f2
[ 8683.928121]  [<c031f4fb>] NF_HOOK.clone.19+0x45/0x4c
[ 8683.928121]  [<c031f524>] arp_xmit+0x22/0x24
[ 8683.928121]  [<c02e02a6>] ? dev_hard_start_xmit+0x3f2/0x3f2
[ 8683.928121]  [<c031f567>] arp_send+0x41/0x48
[ 8683.928121]  [<c031fa7d>] arp_process+0x289/0x491
[ 8683.928121]  [<c031f7f4>] ? __neigh_lookup.clone.20+0x42/0x42
[ 8683.928121]  [<c031f4fb>] NF_HOOK.clone.19+0x45/0x4c
[ 8683.928121]  [<c031f7a0>] arp_rcv+0xb1/0xc3
[ 8683.928121]  [<c031f7f4>] ? __neigh_lookup.clone.20+0x42/0x42
[ 8683.928121]  [<c02de91b>] __netif_receive_skb+0x329/0x378
[ 8683.928121]  [<c02de9d3>] process_backlog+0x69/0x130
[ 8683.928121]  [<c02df103>] net_rx_action+0x90/0x15d
[ 8683.928121]  [<c012b2b5>] __do_softirq+0x7b/0x118
[ 8683.928121]  [<c012b23a>] ? local_bh_enable+0xd/0xd
[ 8683.928121]  <IRQ>  [<c012b4d0>] ? irq_exit+0x41/0x91
[ 8683.928121]  [<c0103c6f>] ? do_IRQ+0x79/0x8d
[ 8683.928121]  [<c0157ea1>] ? trace_hardirqs_off_caller+0x2e/0x86
[ 8683.928121]  [<c034ef6e>] ? common_interrupt+0x2e/0x34
[ 8683.928121]  [<c0108a33>] ? default_idle+0x23/0x38
[ 8683.928121]  [<c01091a8>] ? cpu_idle+0x55/0x6f
[ 8683.928121]  [<c033df25>] ? rest_init+0xa1/0xa7
[ 8683.928121]  [<c033de84>] ? __read_lock_failed+0x14/0x14
[ 8683.928121]  [<c0498745>] ? start_kernel+0x303/0x30a
[ 8683.928121]  [<c0498209>] ? repair_env_string+0x51/0x51
[ 8683.928121]  [<c04980a8>] ? i386_start_kernel+0xa8/0xaf

It appears that like most virtual devices, l2tp should be converted to
LLTX mode.

This patch takes care of statistics using atomic_long in both RX and TX
paths, and fix a bug in l2tp_eth_dev_recv(), which was caching skb->data
before a pskb_may_pull() call.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
Cc: James Chapman <jchapman@katalix.com>
Cc: Hong zhi guo <honkiko@gmail.com>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>