Use i_writecount to control whether to get an fscache cookie in nfs_open() as
NFS does not do write caching yet.  I *think* this is the cause of a problem
encountered by Mark Moseley whereby __fscache_uncache_page() gets a NULL
pointer dereference because cookie->def is NULL:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [<ffffffff812a1903>] __fscache_uncache_page+0x23/0x160
PGD 0
Thread overran stack, or stack corrupted
Oops: 0000 [#1] SMP
Modules linked in: ...
CPU: 7 PID: 18993 Comm: php Not tainted 3.11.1 #1
Hardware name: Dell Inc. PowerEdge R420/072XWF, BIOS 1.3.5 08/21/2012
task: ffff8804203460c0 ti: ffff880420346640
RIP: 0010:[<ffffffff812a1903>] __fscache_uncache_page+0x23/0x160
RSP: 0018:ffff8801053af878 EFLAGS: 00210286
RAX: 0000000000000000 RBX: ffff8800be2f8780 RCX: ffff88022ffae5e8
RDX: 0000000000004c66 RSI: ffffea00055ff440 RDI: ffff8800be2f8780
RBP: ffff8801053af898 R08: 0000000000000001 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00055ff440
R13: 0000000000001000 R14: ffff8800c50be538 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88042fc60000(0063) knlGS:00000000e439c700
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000001d8f000 CR4: 00000000000607f0
Stack:
...
Call Trace:
[<ffffffff81365a72>] __nfs_fscache_invalidate_page+0x42/0x70
[<ffffffff813553d5>] nfs_invalidate_page+0x75/0x90
[<ffffffff811b8f5e>] truncate_inode_page+0x8e/0x90
[<ffffffff811b90ad>] truncate_inode_pages_range.part.12+0x14d/0x620
[<ffffffff81d6387d>] ? __mutex_lock_slowpath+0x1fd/0x2e0
[<ffffffff811b95d3>] truncate_inode_pages_range+0x53/0x70
[<ffffffff811b969d>] truncate_inode_pages+0x2d/0x40
[<ffffffff811b96ff>] truncate_pagecache+0x4f/0x70
[<ffffffff81356840>] nfs_setattr_update_inode+0xa0/0x120
[<ffffffff81368de4>] nfs3_proc_setattr+0xc4/0xe0
[<ffffffff81357f78>] nfs_setattr+0xc8/0x150
[<ffffffff8122d95b>] notify_change+0x1cb/0x390
[<ffffffff8120a55b>] do_truncate+0x7b/0xc0
[<ffffffff8121f96c>] do_last+0xa4c/0xfd0
[<ffffffff8121ffbc>] path_openat+0xcc/0x670
[<ffffffff81220a0e>] do_filp_open+0x4e/0xb0
[<ffffffff8120ba1f>] do_sys_open+0x13f/0x2b0
[<ffffffff8126aaf6>] compat_SyS_open+0x36/0x50
[<ffffffff81d7204c>] sysenter_dispatch+0x7/0x24

The code at the instruction pointer was disassembled:

> (gdb) disas __fscache_uncache_page
> Dump of assembler code for function __fscache_uncache_page:
> ...
> 0xffffffff812a18ff <+31>: mov 0x48(%rbx),%rax
> 0xffffffff812a1903 <+35>: cmpb $0x0,0x10(%rax)
> 0xffffffff812a1907 <+39>: je 0xffffffff812a19cd <__fscache_uncache_page+237>

These instructions make up:

	ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);

That cmpb is the faulting instruction (%rax is 0).  So cookie->def is NULL -
which presumably means that the cookie has already been at least partway
through __fscache_relinquish_cookie().

What I think may be happening is something like a three-way race on the same
file:

	PROCESS 1	PROCESS 2	PROCESS 3
	===============	===============	===============
	open(O_TRUNC|O_WRONLY)
			open(O_RDONLY)
					open(O_WRONLY)
	-->nfs_open()
	-->nfs_fscache_set_inode_cookie()
	nfs_fscache_inode_lock()
	nfs_fscache_disable_inode_cookie()
	__fscache_relinquish_cookie()
	nfs_inode->fscache = NULL
	<--nfs_fscache_set_inode_cookie()

			-->nfs_open()
			-->nfs_fscache_set_inode_cookie()
			nfs_fscache_inode_lock()
			nfs_fscache_enable_inode_cookie()
			__fscache_acquire_cookie()
			nfs_inode->fscache = cookie
			<--nfs_fscache_set_inode_cookie()
	<--nfs_open()
	-->nfs_setattr()
	...
	...
	-->nfs_invalidate_page()
	-->__nfs_fscache_invalidate_page()
	cookie = nfsi->fscache
					-->nfs_open()
					-->nfs_fscache_set_inode_cookie()
					nfs_fscache_inode_lock()
					nfs_fscache_disable_inode_cookie()
					-->__fscache_relinquish_cookie()
	-->__fscache_uncache_page(cookie)
	<crash>
					<--__fscache_relinquish_cookie()
					nfs_inode->fscache = NULL
					<--nfs_fscache_set_inode_cookie()

What is needed is something to prevent process #2 from reacquiring the cookie
- and I think checking i_writecount should do the trick.

It's also possible to have a two-way race on this if the file is opened
O_TRUNC|O_RDONLY instead.
Reported-by: NMark Moseley <moseleymark@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Provide the ability to enable and disable fscache cookies.  A disabled cookie
will reject or ignore further requests to:

	Acquire a child cookie
	Invalidate and update backing objects
	Check the consistency of a backing object
	Allocate storage for backing page
	Read backing pages
	Write to backing pages

but still allows:

	Checks/waits on the completion of already in-progress objects
	Uncaching of pages
	Relinquishment of cookies

Two new operations are provided:

 (1) Disable a cookie:

	void fscache_disable_cookie(struct fscache_cookie *cookie,
				    bool invalidate);

     If the cookie is not already disabled, this locks the cookie against other
     dis/enablement ops, marks the cookie as being disabled, discards or
     invalidates any backing objects and waits for cessation of activity on any
     associated object.

     This is a wrapper around a chunk split out of fscache_relinquish_cookie(),
     but it reinitialises the cookie such that it can be reenabled.

     All possible failures are handled internally.  The caller should consider
     calling fscache_uncache_all_inode_pages() afterwards to make sure all page
     markings are cleared up.

 (2) Enable a cookie:

	void fscache_enable_cookie(struct fscache_cookie *cookie,
				   bool (*can_enable)(void *data),
				   void *data)

     If the cookie is not already enabled, this locks the cookie against other
     dis/enablement ops, invokes can_enable() and, if the cookie is not an
     index cookie, will begin the procedure of acquiring backing objects.

     The optional can_enable() function is passed the data argument and returns
     a ruling as to whether or not enablement should actually be permitted to
     begin.

     All possible failures are handled internally.  The cookie will only be
     marked as enabled if provisional backing objects are allocated.

A later patch will introduce these to NFS.  Cookie enablement during nfs_open()
is then contingent on i_writecount <= 0.  can_enable() checks for a race
between open(O_RDONLY) and open(O_WRONLY/O_RDWR).  This simplifies NFS's cookie
handling and allows us to get rid of open(O_RDONLY) accidentally introducing
caching to an inode that's open for writing already.

One operation has its API modified:

 (3) Acquire a cookie.

	struct fscache_cookie *fscache_acquire_cookie(
		struct fscache_cookie *parent,
		const struct fscache_cookie_def *def,
		void *netfs_data,
		bool enable);

     This now has an additional argument that indicates whether the requested
     cookie should be enabled by default.  It doesn't need the can_enable()
     function because the caller must prevent multiple calls for the same netfs
     object and it doesn't need to take the enablement lock because no one else
     can get at the cookie before this returns.

Signed-off-by: David Howells <dhowells@redhat.com

Add wrapper functions for dealing with cookie->n_active:

 (*) __fscache_use_cookie() to increment it.

 (*) __fscache_unuse_cookie() to decrement and test against zero.

 (*) __fscache_wake_unused_cookie() to wake up anyone waiting for it to reach
     zero.

The second and third are split so that the third can be done after cookie->lock
has been released in case the waiter wakes up whilst we're still holding it and
tries to get it.

We will need to wake-on-zero once the cookie disablement patch is applied
because it will then be possible to see n_active become zero without the cookie
being relinquished.

Also move the cookie usement out of fscache_attr_changed_op() and into
fscache_attr_changed() and the operation struct so that cookie disablement
will be able to track it.

Whilst we're at it, only increment n_active if we're about to do
fscache_submit_op() so that we don't have to deal with undoing it if anything
earlier fails.  Possibly this should be moved into fscache_submit_op() which
could look at FSCACHE_OP_UNUSE_COOKIE.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Pull ACPI and power management fixes from Rafael Wysocki:

 1) Four fixes for cpufreq regressions introduced by the changes that
    removed Device Tree parsing for CPU device nodes from cpufreq
    drivers from Sudeep KarkadaNagesha.

 2) Two fixes for recent cpufreq regressions introduced by changes
    related to the preservation of sysfs attributes over system
    suspend/resume cycles from Viresh Kumar.

 3) Fix for ACPI-based wakeup signaling in the PCI subsystem that
    fails to stop PME polling for devices put into the D3cold power
    state from Rafael J Wysocki.

 4) Fix for bad interactions between cpufreq and udev on systems
    supporting intel_pstate where acpi-cpufreq is available as well
    from Yinghai Lu.

* tag 'pm+acpi-3.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: return EEXIST instead of EBUSY for second registering
  PCI / ACPI / PM: Clear pme_poll for devices in D3cold on wakeup
  ARM: shmobile: change dev_id to cpu0 while registering cpu clock
  ARM: i.MX: change dev_id to cpu0 while registering cpu clock
  cpufreq: imx6q-cpufreq: assign cpu_dev correctly to cpu0 device
  cpufreq: cpufreq-cpu0: assign cpu_dev correctly to cpu0 device
  cpufreq: unlock correct rwsem while updating policy->cpu
  cpufreq: Clear policy->cpus bits in __cpufreq_remove_dev_finish()

Pull vhost updates from Michael Tsirkin:
 "vhost: minor changes on top of 3.12-rc1

  This fixes module loading for vhost-scsi, and tweaks locking in vhost
  core a bit.  Both of these are not exactly release blockers but it's
  early in the cycle so I think it's a good idea to apply them now"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost-scsi: whitespace tweak
  vhost/scsi: use vmalloc for order-10 allocation
  vhost: wake up worker outside spin_lock

Don't try to dump the index key that distinguishes an object if netfs
data in the cookie the object refers to has been cleared (ie.  the
cookie has passed most of the way through
__fscache_relinquish_cookie()).

Since the netfs holds the index key, we can't get at it once the ->def
and ->netfs_data pointers have been cleared - and a NULL pointer
exception will ensue, usually just after a:

	CacheFiles: Error: Unexpected object collision

error is reported.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In cachefiles_check_auxdata(), we allocate auxbuf but fail to free it if
we determine there's an error or that the data is stale.

Further, assigning the output of vfs_getxattr() to auxbuf->len gives
problems with checking for errors as auxbuf->len is a u16.  We don't
actually need to set auxbuf->len, so keep the length in a variable for
now.  We shouldn't need to check the upper limit of the buffer as an
overflow there should be indicated by -ERANGE.

While we're at it, fscache_check_aux() returns an enum value, not an
int, so assign it to an appropriately typed variable rather than to ret.
Signed-off-by: NJosh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Hongyi Jia <jiayisuse@gmail.com>
cc: Milosz Tanski <milosz@adfin.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The cmpxchg() function tends not to support 64-bit arguments on 32-bit
architectures.  This could be either due to use of unsigned long
arguments (like on ARM) or lack of instruction support (cmpxchgq on
x86).  However, these architectures may implement a specific cmpxchg64()
function to provide 64-bit cmpxchg support instead.

Since the lockref code requires a 64-bit cmpxchg and relies on the
architecture selecting ARCH_USE_CMPXCHG_LOCKREF, move to using cmpxchg64
instead of cmpxchg and allow 32-bit architectures to make use of the
lockless lockref implementation.

Cc: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* pm-cpufreq:
  cpufreq: return EEXIST instead of EBUSY for second registering
  ARM: shmobile: change dev_id to cpu0 while registering cpu clock
  ARM: i.MX: change dev_id to cpu0 while registering cpu clock
  cpufreq: imx6q-cpufreq: assign cpu_dev correctly to cpu0 device
  cpufreq: cpufreq-cpu0: assign cpu_dev correctly to cpu0 device
  cpufreq: unlock correct rwsem while updating policy->cpu
  cpufreq: Clear policy->cpus bits in __cpufreq_remove_dev_finish()

* acpi-pci:
  PCI / ACPI / PM: Clear pme_poll for devices in D3cold on wakeup

Pull ARM64 fixes from Catalin Marinas:
 - Compat register fault reporting fix
 - Documentation clarification on tagged pointers
 - hwcap widened to 64-bit (user space already reading it as 64-bit)

* tag 'arm64-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64:
  arm64: Widen hwcap to be 64 bit
  arm64: Correctly report LR and SP for compat tasks
  arm64: documentation: tighten up tagged pointer documentation
  arm64: Make do_bad_area() function static

Under arm64 elf_hwcap is a 32 bit quantity, but it is stored in
a 64 bit auxiliary ELF field and glibc reads hwcap as 64 bit.

This patch widens elf_hwcap to be 64 bit.
Signed-off-by: NSteve Capper <steve.capper@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

When a task crashes and we print debugging information, ensure that
compat tasks show the actual AArch32 LR and SP registers rather than the
AArch64 ones.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Commit d50240a5 ("arm64: mm: permit use of tagged pointers at EL0")
added support for tagged pointers in userspace, but the corresponding
update to Documentation/ contained some imprecise statements.

This patch fixes up some minor ambiguities in the text, hopefully making
it more clear about exactly what the kernel expects from user virtual
addresses.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This function is only called from arch/arm64/mm/fault.c.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Pull ARM SoC fixes from Olof Johansson:
 "A set of fixes for ARM platforms for 3.12.  Among them:

   - A fix for build breakage in the MTD subsystem for some PXA devices.
     David Woodhouse has this patch in his for-next branch but has not
     been responding to our requests to send it up so here it is.  I
     should have amended the commit message to describe the build
     failure for CONFIG_OF=n setups, but forgot and now it's down in the
     stack of commits.

   - Added device-tree for the BeagleBone Black.  Turns out people have
     been using the older "regualar" bone DT for the newer boards, and
     there's risk of damaging hardware that way.

   - Misc DT and regular fixes for OMAP.

   - Fix to make the ST-Ericsson "snowball" boards boot with
     multi_v7_defconfig, and enable one of the ST-E reference boards on
     the same config.

   - Kconfig cleanup for u300 to hide submenus when the platform isn't
     enabled.

   - Enable ARM_ATAG_DTB_COMPAT to let firmware override command line
     when booting with an appended devicetree on non-DT-enabled firmware
     (needed to boot snowball)"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (26 commits)
  ARM: multi_v7: add HREFv60 to multi_v7 defconfig
  ARM: OMAP2+: mux: fix trivial typo in name
  ARM: OMAP4 SMP: Corrected a typo fucntions to functions
  ARM: OMAP4: cpuidle: fix: call cpu_cluster_pm_exit conditionally
  mailbox: remove unnecessary platform_set_drvdata()
  ARM: mach-omap2: gpmc: Fix warning when CONFIG_ARM_LPAE=y
  ARM: OMAP: fix return value check in omap_device_build_from_dt()
  ARM: OMAP4: Fix clock_get error for GPMC during boot
  ARM: sa1100: collie.c: fall back to jedec_probe flash detection
  ARM: u300: hide submenus
  ARM: dts: igep00x0: Add pinmux configuration for MCBSP2
  ARM: dts: Fix muxing and regulator for wl12xx on the SDIO bus for blaze
  ARM: dts: Fix muxing and regulator for wl12xx on the SDIO bus for pandaboard
  mtd: nand: pxa3xx: Remove unneeded ifdef CONFIG_OF
  ARM: multi_v7_defconfig: enable ARM_ATAG_DTB_COMPAT
  ARM: ux500: disable outer cache debug
  ARM: dts: OMAP5: fix ocp2scp DTS data
  ARM: dts: OMAP5: fix reg property size
  ARM: dts: am335x-bone*: add DT for BeagleBone Black
  ARM: dts: omap3-beagle-xm: fix string error in compatible property
  ...

On systems that support intel_pstate, acpi_cpufreq fails to load, and
udev keeps trying until trace gets filled up and kernel crashes.

The root cause is driver return ret from cpufreq_register_driver(),
because when some other driver takes over before, it will return
EBUSY and then udev will keep trying ...

cpufreq_register_driver() should return EEXIST instead so that the
system can boot without appending intel_pstate=disable and still use
intel_pstate.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit 448bd857 (PCI/PM: add PCIe runtime D3cold support) added a
piece of code to pci_acpi_wake_dev() causing that function to behave
in a special way for devices in D3cold (so that their configuration
registers are not accessed before those devices are resumed).
However, it didn't take the clearing of the pme_poll flag into
account.  That has to be done for all devices, even if they are in
D3cold, or pci_pme_list_scan() will not know that wakeup has been
signaled for the device and will poll its PME Status bit
unnecessarily.

Fix the problem by moving the clearing of the pme_poll flag in
pci_acpi_wake_dev() before the code introduced by commit 448bd857.
Reported-and-tested-by: NDavid E. Box <david.e.box@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: 3.6+ <stable@vger.kernel.org> # 3.6+

Pull networking fixes from David Miller:

 1) If the local_df boolean is set on an SKB we have to allocate a
    unique ID even if IP_DF is set in the ipv4 headers, from Ansis
    Atteka.

 2) Some fixups for the new chipset support that went into the sfc
    driver, from Ben Hutchings.

 3) Because SCTP bypasses a good chunk of, and actually duplicates, the
    logic of the ipv6 output path, some IPSEC things don't get done
    properly.  Integrate SCTP better into the ipv6 output path so that
    these problems are fixed and such issues don't get missed in the
    future either.  From Daniel Borkmann.

 4) Fix skge regressions added by the DMA mapping error return checking
    added in v3.10, from Mikulas Patocka.

 5) Kill some more IRQF_DISABLED references, from Michael Opdenacker.

 6) Fix races and deadlocks in the bridging code, from Hong Zhiguo.

 7) Fix error handling in tun_set_iff(), in particular don't leak
    resources.  From Jason Wang.

 8) Prevent format-string injection into xen-netback driver, from Kees
    Cook.

 9) Fix regression added to netpoll ARP packet handling, in particular
    check for the right ETH_P_ARP protocol code.  From Sonic Zhang.

10) Try to deal with AMD IOMMU errors when using r8169 chips, from
    Francois Romieu.

11) Cure freezes due to recent changes in the rt2x00 wireless driver,
    from Stanislaw Gruszka.

12) Don't do SPI transfers (which can sleep) in interrupt context in
    cw1200 driver, from Solomon Peachy.

13) Fix LEDs handling bug in 5720 tg3 chips already handled for 5719.
    From Nithin Sujir.

14) Make xen_netbk_count_skb_slots() count the actual number of slots
    that will be used, taking into consideration packing and other
    issues that the transmit path will run into.  From David Vrabel.

15) Use the correct maximum age when calculating the bridge
    message_age_timer, from Chris Healy.

16) Get rid of memory leaks in mcs7780 IRDA driver, from Alexey
    Khoroshilov.

17) Netfilter conntrack extensions were converted to RCU but are not
    always freed properly using kfree_rcu().  Fix from Michal Kubecek.

18) VF reset recovery not being done correctly in qlcnic driver, from
    Manish Chopra.

19) Fix inverted test in ATM nicstar driver, from Andy Shevchenko.

20) Missing workqueue destroy in cxgb4 error handling, from Wei Yang.

21) Internal switch not initialized properly in bgmac driver, from Rafał
    Miłecki.

22) Netlink messages report wrong local and remote addresses in IPv6
    tunneling, from Ding Zhi.

23) ICMP redirects should not generate socket errors in DCCP and SCTP.
    We're still working out how this should be handled for RAW and UDP
    sockets.  From Daniel Borkmann and Duan Jiong.

24) We've had several bugs wherein the network namespace's loopback
    device gets accessed after it is free'd, NULL it out so that we can
    catch these problems more readily.  From Eric W Biederman.

25) Fix regression in TCP RTO calculations, from Neal Cardwell.

26) Fix too early free of xen-netback network device when VIFs still
    exist.  From Paul Durrant.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (87 commits)
  netconsole: fix a deadlock with rtnl and netconsole's mutex
  netpoll: fix NULL pointer dereference in netpoll_cleanup
  skge: fix broken driver
  ip: generate unique IP identificator if local fragmentation is allowed
  ip: use ip_hdr() in __ip_make_skb() to retrieve IP header
  xen-netback: Don't destroy the netdev until the vif is shut down
  net:dccp: do not report ICMP redirects to user space
  cnic: Fix crash in cnic_bnx2x_service_kcq()
  bnx2x, cnic, bnx2i, bnx2fc: Fix bnx2i and bnx2fc regressions.
  vxlan: Avoid creating fdb entry with NULL destination
  tcp: fix RTO calculated from cached RTT
  drivers: net: phy: cicada.c: clears warning Use #include <linux/io.h> instead of <asm/io.h>
  net loopback: Set loopback_dev to NULL when freed
  batman-adv: set the TAG flag for the vid passed to BLA
  netfilter: nfnetlink_queue: use network skb for sequence adjustment
  net: sctp: rfc4443: do not report ICMP redirects to user space
  net: usb: cdc_ether: use usb.h macros whenever possible
  net: usb: cdc_ether: fix checkpatch errors and warnings
  net: usb: cdc_ether: Use wwan interface for Telit modules
  ip6_tunnels: raddr and laddr are inverted in nl msg
  ...

This bug was introduced by commit
7a163bfb ("netconsole: avoid a crash with
multiple sysfs writers"). In store_enabled() we have the following
sequence: acquire nt->mutex then rtnl, but in the netconsole netdev
notifier we have rtnl then nt->mutex effectively leading to a deadlock.
The NULL pointer dereference that the above commit tries to fix is
actually due to another bug in netpoll_cleanup(). This is fixed by dropping
the mutex from the netdev notifier as it's already protected by rtnl.
Signed-off-by: NNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I've been hitting a NULL ptr deref while using netconsole because the
np->dev check and the pointer manipulation in netpoll_cleanup are done
without rtnl and the following sequence happens when having a netconsole
over a vlan and we remove the vlan while disabling the netconsole:
	CPU 1					CPU2
					removes vlan and calls the notifier
enters store_enabled(), calls
netdev_cleanup which checks np->dev
and then waits for rtnl
					executes the netconsole netdev
					release notifier making np->dev
					== NULL and releases rtnl
continues to dereference a member of
np->dev which at this point is == NULL
Signed-off-by: NNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The patch 136d8f37 broke the skge driver.
Note this part of the patch:
+               if (skge_rx_setup(skge, e, nskb, skge->rx_buf_size) < 0) {
+                       dev_kfree_skb(nskb);
+                       goto resubmit;
+               }
+
                pci_unmap_single(skge->hw->pdev,
                                 dma_unmap_addr(e, mapaddr),
                                 dma_unmap_len(e, maplen),
                                 PCI_DMA_FROMDEVICE);
                skb = e->skb;
                prefetch(skb->data);
-               skge_rx_setup(skge, e, nskb, skge->rx_buf_size);

The function skge_rx_setup modifies e->skb to point to the new skb. Thus,
after this change, the new buffer, not the old, is returned to the
networking stack.

This bug is present in kernels 3.11, 3.11.1 and 3.12-rc1. The patch should
be queued for 3.11-stable.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Reported-by: NVasiliy Glazov <vascom2@gmail.com>
Tested-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If local fragmentation is allowed, then ip_select_ident() and
ip_select_ident_more() need to generate unique IDs to ensure
correct defragmentation on the peer.

For example, if IPsec (tunnel mode) has to encrypt large skbs
that have local_df bit set, then all IP fragments that belonged
to different ESP datagrams would have used the same identificator.
If one of these IP fragments would get lost or reordered, then
peer could possibly stitch together wrong IP fragments that did
not belong to the same datagram. This would lead to a packet loss
or data corruption.
Signed-off-by: NAnsis Atteka <aatteka@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

skb->data already points to IP header, but for the sake of
consistency we can also use ip_hdr() to retrieve it.
Signed-off-by: NAnsis Atteka <aatteka@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Without this patch, if a frontend cycles through states Closing
and Closed (which Windows frontends need to do) then the netdev
will be destroyed and requires re-invocation of hotplug scripts
to restore state before the frontend can move to Connected. Thus
when udev is not in use the backend gets stuck in InitWait.

With this patch, the netdev is left alone whilst the backend is
still online and is only de-registered and freed just prior to
destroying the vif (which is also nicely symmetrical with the
netdev allocation and registration being done during probe) so
no re-invocation of hotplug scripts is required.
Signed-off-by: NPaul Durrant <paul.durrant@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Acked-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pull MIPS updates from Ralf Baechle:
 - Minor updates and fixes to the Octeon ethernet driver in staging
 - A fix to VGA_MAP_MEM() for 64 bit platforms
 - Fix a workaround for 74K/1074K processors
 - The symlink arch/mips/boot/dts/include/dt-bindings was pointing to a
   a file with a name ending in \n.  I think this may have been caused
   by a git bug with with patches sent by email
 - A build fix for VGA console on BCM1480-based systems
 - Fix PCI device access via "/sys/bus/pci/.../resource0" or similar
   work for Alchemy platforms
 - Fix potential data leak on MIPS R5 cores.  This doesn't add proper
   support for any R5 features, just ensures a kernel without such
   support will be secure to run
 - Adding a macros for the CP0 Config5 register to be used by the R5 fix
 - Make get_cycles() actually return something useful where possible
   This also requires a preparatory patch for performance sake
 - Fix a warning about the use of smp_processor_id() in preemptible
   code.  Again this includes a preparatory patch adding the
   infrastructure to be used by the actual patch
 - Finally remove pointless one-line comment

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Fix invalid symbolic link file
  MIPS: PCI: pci-bcm1480: Include missing vt.h header
  MIPS: Disable usermode switching of the FR bit for MIPS R5 CPUs.
  MIPS: Add MIPS R5 config5 register.
  MIPS: PCI: Use pci_resource_to_user to map pci memory space properly
  MIPS: 74K/1074K: Correct erratum workaround.
  MIPS: Cleanup CP0 PRId and CP1 FPIR register access masks
  MIPS: Remove useless comment about kprobe from arch/mips/Makefile
  MIPS: Fix VGA_MAP_MEM macro.
  MIPS: Reimplement get_cycles().
  MIPS: Optimize current_cpu_type() for better code.
  MIPS: Fix accessing to per-cpu data when flushing the cache
  MIPS: Provide nice way to access boot CPU's data.
  staging: octeon-ethernet: rgmii: enable interrupts that we can handle
  staging: octeon-ethernet: remove skb alloc failure warnings
  staging: octeon-ethernet: make dropped packets to consume NAPI budget

Pull ceph fixes from Sage Weil:
 "These fix several bugs with RBD from 3.11 that didn't get tested in
  time for the merge window: some error handling, a use-after-free, and
  a sequencing issue when unmapping and image races with a notify
  operation.

  There is also a patch fixing a problem with the new ceph + fscache
  code that just went in"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  fscache: check consistency does not decrement refcount
  rbd: fix error handling from rbd_snap_name()
  rbd: ignore unmapped snapshots that no longer exist
  rbd: fix use-after free of rbd_dev->disk
  rbd: make rbd_obj_notify_ack() synchronous
  rbd: complete notifies before cleaning up osd_client and rbd_dev
  libceph: add function to ensure notifies are complete

Commit 3b29aa5b [MIPS: add <dt-bindings/> symlink] created a symlink
file in include/dt-bindings.  Even though commit diff is fine, the symlink
is invalid and ls -lb shows a newline character at the end of the filename:

lrwxrwxrwx 1 maddy maddy 35 Sep 19 18:11 dt-bindings ->
../../../../../include/dt-bindings\n
Signed-off-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: steven.hill@imgtec.com
Cc: mmarek@suse.cz
Cc: swarren@nvidia.com
Cc: linux-mips@linux-mips.org
Cc: linux-kbuild@vger.kernel.org
Cc: james.hogan@imgtec.com
Patchwork: https://patchwork.linux-mips.org/patch/5859/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

It's needed for the MAX_NR_CONSOLES macro.

Fixes the following build problem on a randconfig:

arch/mips/pci/pci-bcm1480.c: In function 'bcm1480_pcibios_init':
arch/mips/pci/pci-bcm1480.c:261:36: error: 'MAX_NR_CONSOLES'
undeclared (first use in this function)
arch/mips/pci/pci-bcm1480.c:261:36: note: each undeclared
identifier is reported only once for each function it appears in
make[1]: *** [arch/mips/pci/pci-bcm1480.o] Error 1
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5858/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Currently the kernel will always use the FR=0 register model for O32.  If
an O32 application did enable FR=1 mode, some data from another application
might be leaked in the extra registers becoming visible.

Iow, this patch is meant to make the kernel MIPS R5 tolerant but leaves
proper MIPS R5 support to a future patchset.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Pull drm radeon/nouveau/core fixes from Dave Airlie:
 "Mostly radeon fixes, with some nouveau bios parser, ttm fix and a fix
  for AST driver"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (42 commits)
  drm/fb-helper: don't sleep for screen unblank when an oops is in progress
  drm, ttm Fix uninitialized warning
  drm/ttm: fix the tt_populated check in ttm_tt_destroy()
  drm/nouveau/ttm: prevent double-free in nouveau_sgdma_create_ttm() failure path
  drm/nouveau/bios/init: fix thinko in INIT_CONFIGURE_MEM
  drm/nouveau/kms: enable for non-vga pci classes
  drm/nouveau/bios/init: stub opcode 0xaa
  drm/radeon: avoid UVD corruptions on AGP cards
  drm/radeon: fix panel scaling with eDP and LVDS bridges
  drm/radeon/dpm: rework auto performance level enable
  drm/radeon: Fix hmdi typo
  drm/radeon/dpm/rs780: fix force_performance state for same sclks
  drm/radeon/dpm/rs780: don't enable sclk scaling if not required
  drm/radeon/dpm/rs780: add some sanity checking to sclk scaling
  drm/radeon/dpm/rs780: use drm_mode_vrefresh()
  drm/udl: rip out set_need_resched
  drm/ast: fix the ast open key function
  drm/radeon/dpm: add bapm callback for kb/kv
  drm/radeon/dpm: add bapm callback for trinity
  drm/radeon/dpm: add infrastructure to properly handle bapm
  ...

Otherwise the system will burn even brighter and worse, leave the user
wondering what's going on exactly.

Since we already have a panic handler which will (try) to restore the
entire fbdev console mode, we can just bail out.  Inspired by a patch from
Konstantin Khlebnikov.  The callchain leading to this, cut&pasted from
Konstantin's original patch:

callstack:
panic()
bust_spinlocks(1)
unblank_screen()
vc->vc_sw->con_blank()
fbcon_blank()
fb_blank()
info->fbops->fb_blank()
drm_fb_helper_blank()
drm_fb_helper_dpms()
drm_modeset_lock_all()
mutex_lock(&dev->mode_config.mutex)

Note that the entire locking in the fb helper around panic/sysrq and kdbg
is ...  non-existant.  So we have a decent change of blowing up
everything.  But since reworking this ties in with funny concepts like the
fbdev notifier chain or the impressive things which happen around
console_lock while oopsing, I'll leave that as an exercise for braver
souls than me.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Airlie <airlied@gmail.com>
Reviewed-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Currently all clkdev registration use "cpufreq-cpu0.0" as dev_id
for cpu clock which refers to virtual platform device. It needs to
be "cpu0" instead which is actual cpu0 device id.

This patch changes the dev_id from "cpufreq-cpu0.0" to "cpu0".
Reported-and-tested-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Magnus Damm <damm@opensource.se>
Signed-off-by: NSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently all clkdev registration use "cpufreq-cpu0.0" as dev_id
for cpu clock which refers to virtual platform device. It needs to
be "cpu0" instead which is actual cpu0 device id.

This patch changes the dev_id from "cpufreq-cpu0.0" to "cpu0".
Reported-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit cdc58d60 "cpufreq: imx6q-cpufreq:
remove device tree parsing for cpu nodes" assumed the pdev->dev is set to
cpu0 device in the platform code. But it actually points to the virtual
cpufreq-cpu0 platform device which is not present in the device tree.
Most of the information needed by cpufreq is stored in cpu0 DT node.
So cpu_dev must point to cpu0 device.

This patch fixes the wrong assignment to cpu_dev.
Reported-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit f837a9b5 "cpufreq: cpufreq-cpu0:
remove device tree parsing for cpu nodes" assumed the pdev->dev is set to
cpu0 device in the platform code. But it actually points to the virtual
cpufreq-cpu0 platform device which is not present in the device tree.
Most of the information needed by cpufreq is stored in cpu0 DT node.
So cpu_dev must point to cpu0 device.

This patch fixes the wrong assignment to cpu_dev.
Reported-and-tested-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: NSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Fix uninitialized warning.

drivers/gpu/drm/ttm/ttm_object.c: In function ‘ttm_base_object_lookup’:
drivers/gpu/drm/ttm/ttm_object.c:213:10: error: ‘base’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  kref_put(&base->refcount, ttm_release_base);
          ^
drivers/gpu/drm/ttm/ttm_object.c:221:26: note: ‘base’ was declared here
  struct ttm_base_object *base;
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Reviewed-by: NRob Clark <robdclark@gmail.com>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

After a vmalloc failure in ttm_dma_tt_alloc_page_directory(),
ttm_dma_tt_init() will call ttm_tt_destroy() to cleanup, and end up
inside the driver's unpopulate() hook when populate() has never yet
been called.

On nouveau, the first issue to be hit because of this is that
dma_address[] may be a NULL pointer.  After working around this,
ttm_pool_unpopulate() may potentially hit the same issue with
the pages[] array.

It seems to make more sense to avoid calling unpopulate on already
unpopulated TTMs than to add checks to all the implementations.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>
Reviewed-by: NThomas Hellstrom <thellstrom@vmware.com>
Cc: stable@vger.kernel.org
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Merge branch 'drm-nouveau-next' of git://anongit.freedesktop.org/git/nouveau/linux-2.6 into drm-fixes

A couple of bios parser fixes (one for ancient chips, another for new ones - important in Optimus configs).  Another to make sure KMS is enabled on certain Optimus configs, and a TTM failure path fix.

* 'drm-nouveau-next' of git://anongit.freedesktop.org/git/nouveau/linux-2.6:
  drm/nouveau/ttm: prevent double-free in nouveau_sgdma_create_ttm() failure path
  drm/nouveau/bios/init: fix thinko in INIT_CONFIGURE_MEM
  drm/nouveau/kms: enable for non-vga pci classes
  drm/nouveau/bios/init: stub opcode 0xaa