When proc_pid_attr_write() was changed to use memdup_user apparmor's
(interface violating) assumption that the setprocattr buffer was always
a single page was violated.

The size test is not strictly speaking needed as proc_pid_attr_write()
will reject anything larger, but for the sake of robustness we can keep
it in.

SMACK and SELinux look safe to me, but somebody else should probably
have a look just in case.

Based on original patch from Vegard Nossum <vegard.nossum@oracle.com>
modified for the case that apparmor provides null termination.

Fixes: bb646cdbReported-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: stable@kernel.org
Signed-off-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

Pull block IO fixes from Jens Axboe:
 "Three small fixes that have been queued up and tested for this series:

   - A bug fix for xen-blkfront from Bob Liu, fixing an issue with
     incomplete requests during migration.

   - A fix for an ancient issue in retrieving the IO priority of a
     different PID than self, preventing that task from going away while
     we access it.  From Omar.

   - A writeback fix from Tahsin, fixing a case where we'd call ihold()
     with a zero ref count inode"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix use-after-free in sys_ioprio_get()
  writeback: inode cgroup wb switch should not call ihold()
  xen-blkfront: save uncompleted reqs in blkfront_resume()

Pull configfs fix from Christoph Hellwig:
 "A fix from Marek for ppos handling in configfs_write_bin_file, which
  was introduced in Linux 4.5, but didn't have any users until recently"

* tag 'configfs-for-4.7' of git://git.infradead.org/users/hch/configfs:
  configfs: Remove ppos increment in configfs_write_bin_file

The "expert" menu was broken (split) such that all entries in it after
KALLSYMS were displayed in the "General setup" area instead of in the
"Expert users" area.  Fix this by adding one kconfig dependency.

Yes, the Expert users menu is fragile.  Problems like this have happened
several times in the past.  I will attempt to isolate the Expert users
menu if there is interest in that.

Fixes: 4d5d5664 ("x86: kallsyms: disable absolute percpu symbols on !SMP")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: stable@vger.kernel.org  # 4.6
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull networking fixes from David Miller:

 1) All users of AF_PACKET's fanout feature want a symmetric packet
    header hash for load balancing purposes, so give it to them.

 2) Fix vlan state synchronization in e1000e, from Jarod Wilson.

 3) Use correct socket pointer in ip_skb_dst_mtu(), from Shmulik
    Ladkani.

 4) mlx5 bug fixes from Mohamad Haj Yahia, Daniel Jurgens, Matthew
    Finlay, Rana Shahout, and Shaker Daibes.  Mostly to do with
    operation timeouts and PCI error handling.

 5) Fix checksum handling in mirred packet action, from WANG Cong.

 6) Set skb->dev correctly when transmitting in !protect_frames case of
    macsec driver, from Daniel Borkmann.

 7) Fix MTU calculation in geneve driver, from Haishuang Yan.

 8) Missing netif_napi_del() in unregister path of qeth driver, from
    Ursula Braun.

 9) Handle malformed route netlink messages in decnet properly, from
    Vergard Nossum.

10) Memory leak of percpu data in ipv6 routing code, from Martin KaFai
    Lau.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (41 commits)
  ipv6: Fix mem leak in rt6i_pcpu
  net: fix decnet rtnexthop parsing
  cxgb4: update latest firmware version supported
  net/mlx5: Avoid setting unused var when modifying vport node GUID
  bonding: fix enslavement slave link notifications
  r8152: fix runtime function for RTL8152
  qeth: delete napi struct when removing a qeth device
  Revert "fsl/fman: fix error handling"
  fsl/fman: fix error handling
  cdc_ncm: workaround for EM7455 "silent" data interface
  RDS: fix rds_tcp_init() error path
  geneve: fix max_mtu setting
  net: phy: dp83867: Fix initialization of PHYCR register
  enc28j60: Fix race condition in enc28j60 driver
  net: stmmac: Fix null-function call in ISR on stmmac1000
  tipc: fix nl compat regression for link statistics
  net: bcmsysport: Device stats are unsigned long
  macsec: set actual real device for xmit when !protect_frames
  net_sched: fix mirrored packets checksum
  packet: Use symmetric hash for PACKET_FANOUT_HASH.
  ...

Pull sound fixes from Takashi Iwai:
 "Here are a collection of small fixes: at this time, we've got a
  slightly high amount, but all small and trivial fixes, and nothing
  scary can be seen there"

* tag 'sound-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (21 commits)
  ALSA: hda/realtek: Add Lenovo L460 to docking unit fixup
  ALSA: timer: Fix negative queue usage by racy accesses
  ASoC: rt5645: fix reg-2f default value.
  ASoC: fsl_ssi: Fix number of words per frame for I2S-slave mode
  ALSA: au88x0: Fix calculation in vortex_wtdma_bufshift()
  ALSA: hda - Add PCI ID for Kabylake-H
  ALSA: echoaudio: Fix memory allocation
  ASoC: Intel: atom: fix missing breaks that would cause the wrong operation to execute
  ALSA: hda - fix read before array start
  ASoC: cx20442: set tty->receiver_room in v253_open
  ASoC: ak4613: Enable cache usage to fix crashes on resume
  ASoC: wm8940: Enable cache usage to fix crashes on resume
  ASoC: Intel: Skylake: Initialize module list for Broxton
  ASoC: wm5102: Correct supported channels on trace compressed DAI
  ASoC: wm5110: Add missing route from OUT3R to SYSCLK
  ASoC: rt5670: fix HP Playback Volume control
  ASoC: hdmi-codec: select CONFIG_HDMI
  ASoC: davinci-mcasp: Fix dra7 DMA offset when using CFG port
  ASoC: hdac_hdmi: Fix potential NULL dereference
  ASoC: ak4613: Remove owner assignment from platform_driver
  ...

Pull chrome platform fix from Olof Johansson:
 "A single fix this time, closing a window where ioctl args are fetched
  twice"

* tag 'chrome-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform:
  platform/chrome: cros_ec_dev - double fetch bug in ioctl

It was first reported and reproduced by Petr (thanks!) in
https://bugzilla.kernel.org/show_bug.cgi?id=119581

free_percpu(rt->rt6i_pcpu) used to always happen in ip6_dst_destroy().

However, after fixing a deadlock bug in
commit 9c7370a1 ("ipv6: Fix a potential deadlock when creating pcpu rt"),
free_percpu() is not called before setting non_pcpu_rt->rt6i_pcpu to NULL.

It is worth to note that rt6i_pcpu is protected by table->tb6_lock.

kmemleak somehow did not report it.  We nailed it down by
observing the pcpu entries in /proc/vmallocinfo (first suggested
by Hannes, thanks!).
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Fixes: 9c7370a1 ("ipv6: Fix a potential deadlock when creating pcpu rt")
Reported-by: Petr Novopashenniy <pety@rusnet.ru>
Tested-by: Petr Novopashenniy <pety@rusnet.ru>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Petr Novopashenniy <pety@rusnet.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

dn_fib_count_nhs() could enter an infinite loop if nhp->rtnh_len == 0
(i.e. if userspace passes a malformed netlink message).

Let's use the helpers from net/nexthop.h which take care of all this
stuff. We can do exactly the same as e.g. fib_count_nexthops() and
fib_get_nhs() from net/ipv4/fib_semantics.c.

This fixes the softlockup for me.

Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We verify "u_cmd.outsize" and "u_cmd.insize" but we need to make sure
that those values have not changed between the two copy_from_user()
calls.  Otherwise it could lead to a buffer overflow.

Additionally, cros_ec_cmd_xfer() can set s_cmd->insize to a lower value.
We should use the new smaller value so we don't copy too much data to
the user.
Reported-by: Pengfei Wang <wpengfeinudt@gmail.com>
Fixes: a8411784 ('mfd: cros_ec: Use a zero-length array for command data')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Olof Johansson <olof@lixom.net>

Change t4fw_version.h to update latest firmware version number
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

GCC complains on unused-but-set-variable, clean this up.

Fixes: 23898c76 ('net/mlx5: E-Switch, Modify node guid on vf set MAC')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently, link notifications are not sent by
bond_set_slave_link_state() upon enslavement if
the slave is enslaved when up.

This happens because slave->link default init value
is 0, which is the same as BOND_LINK_UP, resulting
in bond_set_slave_link_state() ignoring this transition.

This patch sets the default value of slave->link to
BOND_LINK_NOCHANGE, assuring it will count as a state
transition and thus trigger notification logic.
Signed-off-by: Aviv Heller <avivh@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The RTL8152 doesn't have U1U2 and U2P3 features, so use different
runtime functions for RTL812 and RTL8153 by adding autosuspend_en()
to rtl_ops.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This solves the issue that a headphone is not working on the docking
unit.
Signed-off-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

A qeth_card contains a napi_struct linked to the net_device during
device probing. This struct must be deleted when removing the qeth
device, otherwise Panic on oops can occur when qeth devices are
repeatedly removed and added.

Fixes: a1c3ed4c ("qeth: NAPI support for l2 and l3 discipline")
Cc: stable@vger.kernel.org # v2.6.37+
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Tested-by: Alexander Klein <ALKL@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit a788a4a0.

This patch is wrong, the type returned doesn't fit
what the error pointer macros expect.
Signed-off-by: David S. Miller <davem@davemloft.net>

This is likely that checking 'fman->fifo_offset' instead of
'fman->cam_offset' is expected here.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

Several Lenovo users have reported problems with their Sierra
Wireless EM7455 modem. The driver has loaded successfully and
the MBIM management channel has appeared to work, including
establishing a connection to the mobile network. But no frames
have been received over the data interface.

The problem affects all EM7455 and MC7455, and is assumed to
affect other modems based on the same Qualcomm chipset and
baseband firmware.

Testing narrowed the problem down to what seems to be a
firmware timing bug during initialization. Adding a short sleep
while probing is sufficient to make the problem disappear.
Experiments have shown that 1-2 ms is too little to have any
effect, while 10-20 ms is enough to reliably succeed.
Reported-by: Stefan Armbruster <ml001@armbruster-it.de>
Reported-by: Ralph Plawetzki <ralph@purejava.org>
Reported-by: Andreas Fett <andreas.fett@secunet.com>
Reported-by: Rasmus Lerdorf <rasmus@lerdorf.com>
Reported-by: Samo Ratnik <samo.ratnik@gmail.com>
Reported-and-tested-by: Aleksander Morgado <aleksander@aleksander.es>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

If register_pernet_subsys() fails, we shouldn't try to call
unregister_pernet_subsys().

Fixes: 467fa153 ("RDS-TCP: Support multiple RDS-TCP listen endpoints, one per netns.")
Cc: stable@vger.kernel.org
Cc: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

For ipv6+udp+geneve encapsulation data, the max_mtu should subtract
sizeof(ipv6hdr), instead of sizeof(iphdr).
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The user timer tu->qused counter may go to a negative value when
multiple concurrent reads are performed since both the check and the
decrement of tu->qused are done in two individual locked contexts.
This results in bogus read outs, and the endless loop in the
user-space side.

The fix is to move the decrement of the tu->qused counter into the
same spinlock context as the zero-check of the counter.

Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Pull fuse fix from Miklos Szeredi:
 "This makes sure userspace filesystems are not broken by the parallel
  lookups and readdir feature"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: serialize dirops by default

Pull overlayfs fixes from Miklos Szeredi:
 "This contains fixes for a dentry leak, a regression in 4.6 noticed by
  Docker users and missing write access checking in truncate"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: warn instead of error if d_type is not supported
  ovl: get_write_access() in truncate
  ovl: fix dentry leak for default_permissions

overlay needs underlying fs to support d_type. Recently I put in a
patch in to detect this condition and started failing mount if
underlying fs did not support d_type.

But this breaks existing configurations over kernel upgrade. Those who
are running docker (partially broken configuration) with xfs not
supporting d_type, are surprised that after kernel upgrade docker does
not run anymore.

https://github.com/docker/docker/issues/22937#issuecomment-229881315

So instead of erroring out, detect broken configuration and warn
about it. This should allow existing docker setups to continue
working after kernel upgrade.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 45aebeaf ("ovl: Ensure upper filesystem supports d_type")
Cc: <stable@vger.kernel.org> 4.6

Pull MIPS fix from Ralf Baechle:
 "Only a single fix for 4.7 pending at this point.  It fixes an issue
  that may lead to corruption of the cache mode bits in the page table"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Fix possible corruption of cache mode by mprotect.

Pull powerpc fixes from Michael Ellerman:

 - tm: Always reclaim in start_thread() for exec() class syscalls from
   Cyril Bur

 - tm: Avoid SLB faults in treclaim/trecheckpoint when RI=0 from Michael
   Neuling

 - eeh: Fix wrong argument passed to eeh_rmv_device() from Gavin Shan

 - Initialise pci_io_base as early as possible from Darren Stevens

* tag 'powerpc-4.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc: Initialise pci_io_base as early as possible
  powerpc/tm: Avoid SLB faults in treclaim/trecheckpoint when RI=0
  powerpc/eeh: Fix wrong argument passed to eeh_rmv_device()
  powerpc/tm: Always reclaim in start_thread() for exec() class syscalls

When initializing the PHY control register, the FIFO depth bits are
written without reading the previous register value, i.e. all other
bits are overwritten with zero. This disables automatic MDI-X
configuration, which is enabled by default. Fix initialization by doing
a read/modify/write operation.
Signed-off-by: Stefan Hauser <stefan@shauser.net>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The interrupt worker code for the enc28j60 relies only on the TXIF flag to
determinate if the packet transmission was completed. However the datasheet
specifies in section 12.1.3 that TXERIF will clear the TXRTS after a
transmit abort. Also in section 12.1.4 that TXIF will be set
when TXRTS transitions from '1' to '0'. Therefore the TXIF flag is enabled
during transmission errors.

This causes a race condition, since the worker code will invoke
enc28j60_tx_clear() -> netif_wake_queue(), potentially invoking the
ndo_start_xmit function to send a new packet. The enc28j60_send_packet function
uses a workqueue that invokes enc28j60_hw_tx(). In between this function is
called, the worker from the interrupt handler will enter the path for error
handler because of the TXERIF flag, causing to invoke enc28j60_tx_clear() again
and releasing the packet scheduled for transmission, causing a kernel crash with
due a NULL pointer.

These crashes due a NULL pointer were observed under stress conditions of the
device. A BUG_ON() sequence was used to validate the issue was fixed, and has
been running without problems for 2 years now.
Signed-off-by: Diego Dompe <dompe@hpe.com>
Acked-by: Sergio Valverde <sergio.valverde@hpe.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

(resent due to overhelpful mail client corrupting patch)

At least on Meson GXBB, the CORE_IRQ_MTL_RX_OVERFLOW interrupt is thrown
with the stmmac1000 driver, which does not support set_rx_tail_ptr. With
this patch and the clock fixes, 1G ethernet works on ODROID-C2.
Signed-off-by: Matt Corallo <git@bluematt.me>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull drm fixes frlm Dave Airlie:
 "Just some AMD and Intel fixes, the AMD ones are further production
  Polaris fixes, and the Intel ones fix some early timeouts, some PCI ID
  changes and a couple of other fixes.

  Still a bit Internet challenged here, hopefully end of next week will
  solve it"

* tag 'drm-fixes-for-v4.7-rc6' of git://people.freedesktop.org/~airlied/linux:
  drm/i915: Fix missing unlock on error in i915_ppgtt_info()
  drm/amd/powerplay: workaround for UVD clock issue
  drm/amdgpu: add ACLK_CNTL setting for polaris10
  drm/amd/powerplay: fix issue uvd dpm can't enabled on Polaris11.
  drm/amd/powerplay: Workaround for Memory EDC Error on Polaris10.
  drm/i915: Removing PCI IDs that are no longer listed as Kabylake.
  drm/i915: Add more Kabylake PCI IDs.
  drm/i915: Avoid early timeout during AUX transfers
  drm/i915/hsw: Avoid early timeout during LCPLL disable/restore
  drm/i915/lpt: Avoid early timeout during FDI PHY reset
  drm/i915/bxt: Avoid early timeout during PLL enable
  drm/i915: Refresh cached DP port register value on resume
  drm/amd/powerplay: Update CKS on/ CKS off voltage offset calculation
  drm/amd/powerplay: disable FFC.
  drm/amd/powerplay: add some definition for FFC feature on polaris.

Pull spi fixes from Mark Brown:
 "A few small driver-specific fixes for SPI, all in the normal important
  if you hit them category especially the rockchip driver fix which
  addresses a race which has been exposed more frequently with some
  recent performance improvements"

* tag 'spi-fix-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: sunxi: fix transfer timeout
  spi: sun4i: fix FIFO limit
  spi: rockchip: Signal unfinished DMA transfers
  spi: spi-ti-qspi: Suspend the queue before removing the device

Merge tag 'regulator-fix-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator

Pull regulator fixes from Mark Brown:
 "Two small fixes for the regulator subsystem - one fixing a crash with
  one of the devices supported by the max77620 driver, another fixing
  startup for the anatop regulator when it starts up with the regulator
  in bypass mode"

* tag 'regulator-fix-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: max77620: check for valid regulator info
  regulator: anatop: allow regulator to be in bypass mode

Pull clk fixes from Stephen Boyd:
 "A small fix for the newly added oxnas clk driver and a handful of
  rockchip clk driver fixes for newly added rk3399 support"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: Fix return value check in oxnas_stdclk_probe()
  clk: rockchip: release io resource when failing to init clk on rk3399
  clk: rockchip: fix cpuclk registration error handling
  clk: rockchip: Revert "clk: rockchip: reset init state before mmc card initialization"
  clk: rockchip: fix incorrect parent for rk3399's {c,g}pll_aclk_perihp_src
  clk: rockchip: mark rk3399 GIC clocks as critical
  clk: rockchip: initialize flags of clk_init_data in mmc-phase clock

Merge tag 'asoc-fix-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v4.7

A small clutch of hardware specific fixes for various ASoC devices, all
small individually and important if you have that device but not
otherwise.

here's a batch of i915 fixes for 4.7.

* tag 'drm-intel-fixes-2016-06-30' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Fix missing unlock on error in i915_ppgtt_info()
  drm/i915: Removing PCI IDs that are no longer listed as Kabylake.
  drm/i915: Add more Kabylake PCI IDs.
  drm/i915: Avoid early timeout during AUX transfers
  drm/i915/hsw: Avoid early timeout during LCPLL disable/restore
  drm/i915/lpt: Avoid early timeout during FDI PHY reset
  drm/i915/bxt: Avoid early timeout during PLL enable
  drm/i915: Refresh cached DP port register value on resume

Just a few more late fixes for Polaris cards.

* 'drm-fixes-4.7' of git://people.freedesktop.org/~agd5f/linux:
  drm/amd/powerplay: workaround for UVD clock issue
  drm/amdgpu: add ACLK_CNTL setting for polaris10
  drm/amd/powerplay: fix issue uvd dpm can't enabled on Polaris11.
  drm/amd/powerplay: Workaround for Memory EDC Error on Polaris10.
  drm/amd/powerplay: Update CKS on/ CKS off voltage offset calculation
  drm/amd/powerplay: disable FFC.
  drm/amd/powerplay: add some definition for FFC feature on polaris.

The following testcase may result in a page table entries with a invalid
CCA field being generated:

static void *bindstack;

static int sysrqfd;

static void protect_low(int protect)
{
	mprotect(bindstack, BINDSTACK_SIZE, protect);
}

static void sigbus_handler(int signal, siginfo_t * info, void *context)
{
	void *addr = info->si_addr;

	write(sysrqfd, "x", 1);

	printf("sigbus, fault address %p (should not happen, but might)\n",
	       addr);
	abort();
}

static void run_bind_test(void)
{
	unsigned int *p = bindstack;

	p[0] = 0xf001f001;

	write(sysrqfd, "x", 1);

	/* Set trap on access to p[0] */
	protect_low(PROT_NONE);

	write(sysrqfd, "x", 1);

	/* Clear trap on access to p[0] */
	protect_low(PROT_READ | PROT_WRITE | PROT_EXEC);

	write(sysrqfd, "x", 1);

	/* Check the contents of p[0] */
	if (p[0] != 0xf001f001) {
		write(sysrqfd, "x", 1);

		/* Reached, but shouldn't be */
		printf("badness, shouldn't happen but does\n");
		abort();
	}
}

int main(void)
{
	struct sigaction sa;

	sysrqfd = open("/proc/sysrq-trigger", O_WRONLY);

	if (sigprocmask(SIG_BLOCK, NULL, &sa.sa_mask)) {
		perror("sigprocmask");
		return 0;
	}

	sa.sa_sigaction = sigbus_handler;
	sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART;
	if (sigaction(SIGBUS, &sa, NULL)) {
		perror("sigaction");
		return 0;
	}

	bindstack = mmap(NULL,
			 BINDSTACK_SIZE,
			 PROT_READ | PROT_WRITE | PROT_EXEC,
			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	if (bindstack == MAP_FAILED) {
		perror("mmap bindstack");
		return 0;
	}

	printf("bindstack: %p\n", bindstack);

	run_bind_test();

	printf("done\n");

	return 0;
}

There are multiple ingredients for this:

 1) PAGE_NONE is defined to _CACHE_CACHABLE_NONCOHERENT, which is CCA 3
    on all platforms except SB1 where it's CCA 5.
 2) _page_cachable_default must have bits set which are not set
    _CACHE_CACHABLE_NONCOHERENT.
 3) Either the defective version of pte_modify for XPA or the standard
    version must be in used.  However pte_modify for the 36 bit address
    space support is no affected.

In that case additional bits in the final CCA mode may generate an invalid
value for the CCA field.  On the R10000 system where this was tracked
down for example a CCA 7 has been observed, which is Uncached Accelerated.

Fixed by:

 1) Using the proper CCA mode for PAGE_NONE just like for all the other
    PAGE_* pte/pmd bits.
 2) Fix the two affected variants of pte_modify.

Further code inspection also shows the same issue to exist in pmd_modify
which would affect huge page systems.

Issue in pte_modify tracked down by Alastair Bridgewater, PAGE_NONE
and pmd_modify issue found by me.

The history of this goes back beyond Linus' git history.  Chris Dearman's
commit 35133692 ("[MIPS] Allow setting of
the cache attribute at run time.") missed the opportunity to fix this
but it was originally introduced in lmo commit
d523832cf12007b3242e50bb77d0c9e63e0b6518 ("Missing from last commit.")
and 32cc38229ac7538f2346918a09e75413e8861f87 ("New configuration option
CONFIG_MIPS_UNCACHED.")
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reported-by: Alastair Bridgewater <alastair.bridgewater@gmail.com>

Pull ACPI fix from Rafael Wysocki:
 "Fix an expression in the ACPI PCI IRQ management code added by a
  recent commit that overlooked missing parens in it, so the result of
  the computation is incorrect in some cases (Sinan Kaya)"

* tag 'acpi-4.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI,PCI,IRQ: correct operator precedence