Pull misc SCSI updates from James Bottomley:
 "This is an assorted set of stragglers into the merge window with
  driver updates for megaraid_sas, lpfc, bfi and mvumi.  It also
  includes some fairly major fixes for virtio-scsi (scatterlist init),
  scsi_debug (off by one error), storvsc (use after free) and qla2xxx
  (potential deadlock).

Signed-off-by: James Bottomley <JBottomley@Parallels.com&gt;">

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (49 commits)
  [SCSI] storvsc: Account for in-transit packets in the RESET path
  [SCSI] qla2xxx: fix potential deadlock on ha->hardware_lock
  [SCSI] scsi_debug: Fix off-by-one bug when unmapping region
  [SCSI] Shorten the path length of scsi_cmd_to_driver()
  [SCSI] virtio-scsi: support online resizing of disks
  [SCSI] virtio-scsi: fix LUNs greater than 255
  [SCSI] virtio-scsi: initialize scatterlist structure
  [SCSI] megaraid_sas: Version, Changelog, Copyright update
  [SCSI] megaraid_sas: Remove duplicate code
  [SCSI] megaraid_sas: Add SystemPD FastPath support
  [SCSI] megaraid_sas: Add array boundary check for SystemPD
  [SCSI] megaraid_sas: Load io_request DataLength in bytes
  [SCSI] megaraid_sas: Add module param for configurable MSI-X vector count
  [SCSI] megaraid_sas: Remove un-needed completion_lock spinlock calls
  [SCSI] lpfc 8.3.35: Update lpfc version for 8.3.35 driver release
  [SCSI] lpfc 8.3.35: Fixed not reporting logical link speed to SCSI midlayer when QoS not on
  [SCSI] lpfc 8.3.35: Fix error with fabric service parameters causing performance issues
  [SCSI] lpfc 8.3.35: Fixed SCSI host create showing wrong link speed on SLI3 HBA ports
  [SCSI] lpfc 8.3.35: Fixed not checking solicition in progress bit when verifying FCF record for use
  [SCSI] lpfc 8.3.35: Fixed messages for misconfigured port errors
  ...

Pull input layer updates from Dmitry Torokhov:
 "2nd round of updates for the input subsystem.  With it input core no
  longer limits number of character devices per event handler (such as
  evdev) to 32, but switches to dynamic minors once legacy range is
  exhausted.  This should get multi-seat installations that currently
  run our of event devices very quickly.

  You will also get an update for Wacom driver and a couple of driver
  fixes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: extend the number of event (and other) devices
  Input: mousedev - mark mousedev interfaces as non-seekable
  Input: mousedev - rename mixdev_open to opened_by_mixdev
  Input: mousedev - reformat structure initializers
  Input: mousedev - factor out psaux code to reduce #ifdefery
  Input: samsung-keypad - add clk_prepare and clk_unprepare
  Input: atmel_mxt_ts - simplify mxt_dump_message
  Input: wacom - clean up wacom_query_tablet_data
  Input: wacom - introduce wacom_fix_phy_from_hid
  Input: wacom - allow any multi-input Intuos device to set prox
  Input: wacom - report correct touch contact size for I5/Bamboo

Pull nfsd update from J Bruce Fields:
 "Another relatively quiet cycle.  There was some progress on my
  remaining 4.1 todo's, but a couple of them were just of the form
  "check that we do X correctly", so didn't have much affect on the
  code.

  Other than that, a bunch of cleanup and some bugfixes (including an
  annoying NFSv4.0 state leak and a busy-loop in the server that could
  cause it to peg the CPU without making progress)."

* 'for-3.7' of git://linux-nfs.org/~bfields/linux: (46 commits)
  UAPI: (Scripted) Disintegrate include/linux/sunrpc
  UAPI: (Scripted) Disintegrate include/linux/nfsd
  nfsd4: don't allow reclaims of expired clients
  nfsd4: remove redundant callback probe
  nfsd4: expire old client earlier
  nfsd4: separate session allocation and initialization
  nfsd4: clean up session allocation
  nfsd4: minor free_session cleanup
  nfsd4: new_conn_from_crses should only allocate
  nfsd4: separate connection allocation and initialization
  nfsd4: reject bad forechannel attrs earlier
  nfsd4: enforce per-client sessions/no-sessions distinction
  nfsd4: set cl_minorversion at create time
  nfsd4: don't pin clientids to pseudoflavors
  nfsd4: fix bind_conn_to_session xdr comment
  nfsd4: cast readlink() bug argument
  NFSD: pass null terminated buf to kstrtouint()
  nfsd: remove duplicate init in nfsd4_cb_recall
  nfsd4: eliminate redundant nfs4_free_stateid
  fs/nfsd/nfs4idmap.c: adjust inconsistent IS_ERR and PTR_ERR
  ...

Pull networking updates from David Miller:

 1) Alexey Kuznetsov noticed we routed TCP resets improperly in the
    assymetric routing case, fix this by reverting a change that made us
    use the incoming interface in the outgoing route key when we didn't
    have a socket context to work with.

 2) TCP sysctl kernel memory leakage to userspace fix from Alan Cox.

 3) Move UAPI bits from David Howells, WIMAX and CAN this time.

 4) Fix TX stalls in e1000e wrt.  Byte Queue Limits, from Hiroaki
    SHIMODA, Denys Fedoryshchenko, and Jesse Brandeburg.

 5) Fix IPV6 crashes in packet generator module, from Amerigo Wang.

 6) Tidies and fixes in the new VXLAN driver from Stephen Hemminger.

 7) Bridge IP options parse doesn't check first if SKB header has at
    least an IP header's worth of content present.  Fix from Sarveshwar
    Bandi.

 8) The kernel now generates compound pages on transmit and the Xen
    netback drivers needs some adjustments in order to handle this.  Fix
    from Ian Campbell.

 9) Turn off ASPM in JME driver, from Kevin Bardon and Matthew Garrett.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (43 commits)
  mcs7830: Fix link state detection
  net: add doc for in4_pton()
  net: add doc for in6_pton()
  vti: fix sparse bit endian warnings
  tcp: resets are misrouted
  usbnet: Support devices reporting idleness
  Add CDC-ACM support for the CX93010-2x UCMxx USB Modem
  net/ethernet/jme: disable ASPM
  tcp: sysctl interface leaks 16 bytes of kernel memory
  kaweth: print correct debug ptr
  e1000e: Change wthresh to 1 to avoid possible Tx stalls
  ipv4: fix route mark sparse warning
  xen: netback: handle compound page fragments on transmit.
  bridge: Pull ip header into skb->data before looking into ip header.
  isdn: fix a wrapping bug in isdn_ppp_ioctl()
  vxlan: fix oops when give unknown ifindex
  vxlan: fix receive checksum handling
  vxlan: add additional headroom
  vxlan: allow configuring port range
  vxlan: associate with tunnel socket on transmit
  ...

Pull Sparc updates from David Miller:

 1) Updated syscall tracing fix from Al Viro.

 2) SUN4V error reporting was deficient in several areas.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: fix ptrace interaction with force_successful_syscall_return()
  sparc64: Fix deficiencies in sun4v error reporting.

Pull tile arch update from Chris Metcalf:
 "The bulk of this change is the tile uapi disintegration.  There is
  also a one-line change in here to enable interrupts in
  do_work_pending() to avoid a WARN_ON in _local_bh_enable_ip()."

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: enable interrupts in do_work_pending()
  UAPI: (Scripted) Disintegrate arch/tile/include/asm
  UAPI: (Scripted) Disintegrate arch/tile/include/arch

Pull ia64 UAPI changes from Tony Luck:
 "ia64 pieces of David Howells great UAPI include file move"

* tag 'please-pull-dhowells-uapi' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  UAPI: (Scripted) Disintegrate arch/ia64/include/asm

Pull perf updates from Ingo Molnar:
 "This tree includes some late late perf items that missed the first
  round:

  tools:

   - Bash auto completion improvements, now we can auto complete the
     tools long options, tracepoint event names, etc, from Namhyung Kim.

   - Look up thread using tid instead of pid in 'perf sched'.

   - Move global variables into a perf_kvm struct, from David Ahern.

   - Hists refactorings, preparatory for improved 'diff' command, from
     Jiri Olsa.

   - Hists refactorings, preparatory for event group viewieng work, from
     Namhyung Kim.

   - Remove double negation on optional feature macro definitions, from
     Namhyung Kim.

   - Remove several cases of needless global variables, on most
     builtins.

   - misc fixes

  kernel:

   - sysfs support for IBS on AMD CPUs, from Robert Richter.

   - Support for an upcoming Intel CPU, the Xeon-Phi / Knights Corner
     HPC blade PMU, from Vince Weaver.

   - misc fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  perf: Fix perf_cgroup_switch for sw-events
  perf: Clarify perf_cpu_context::active_pmu usage by renaming it to ::unique_pmu
  perf/AMD/IBS: Add sysfs support
  perf hists: Add more helpers for hist entry stat
  perf hists: Move he->stat.nr_events initialization to a template
  perf hists: Introduce struct he_stat
  perf diff: Removing the total_period argument from output code
  perf tool: Add hpp interface to enable/disable hpp column
  perf tools: Removing hists pair argument from output path
  perf hists: Separate overhead and baseline columns
  perf diff: Refactor diff displacement possition info
  perf hists: Add struct hists pointer to struct hist_entry
  perf tools: Complete tracepoint event names
  perf/x86: Add support for Intel Xeon-Phi Knights Corner PMU
  perf evlist: Remove some unused methods
  perf evlist: Introduce add_newtp method
  perf kvm: Move global variables into a perf_kvm struct
  perf tools: Convert to BACKTRACE_SUPPORT
  perf tools: Long option completion support for each subcommands
  perf tools: Complete long option names of perf command
  ...

Perf build fails with the new rbtree implementation:

  ../../lib/rbtree.c:24:36: fatal error: linux/rbtree_augmented.h: No such file or directory compilation terminated.

Fix by updating the Makefile and adding a btree_augmented.h
wrapper.

Reported-and-tested-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Borislav Petkov <bp@amd64.org>
Link: http://lkml.kernel.org/r/20121009180156.GA245@x4


Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull third pile of kernel_execve() patches from Al Viro:
 "The last bits of infrastructure for kernel_thread() et.al., with
  alpha/arm/x86 use of those.  Plus sanitizing the asm glue and
  do_notify_resume() on alpha, fixing the "disabled irq while running
  task_work stuff" breakage there.

  At that point the rest of kernel_thread/kernel_execve/sys_execve work
  can be done independently for different architectures.  The only
  pending bits that do depend on having all architectures converted are
  restrictred to fs/* and kernel/* - that'll obviously have to wait for
  the next cycle.

  I thought we'd have to wait for all of them done before we start
  eliminating the longjump-style insanity in kernel_execve(), but it
  turned out there's a very simple way to do that without flagday-style
  changes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  alpha: switch to saner kernel_execve() semantics
  arm: switch to saner kernel_execve() semantics
  x86, um: convert to saner kernel_execve() semantics
  infrastructure for saner ret_from_kernel_thread semantics
  make sure that kernel_thread() callbacks call do_exit() themselves
  make sure that we always have a return path from kernel_execve()
  ppc: eeh_event should just use kthread_run()
  don't bother with kernel_thread/kernel_execve for launching linuxrc
  alpha: get rid of switch_stack argument of do_work_pending()
  alpha: don't bother passing switch_stack separately from regs
  alpha: take SIGPENDING/NOTIFY_RESUME loop into signal.c
  alpha: simplify TIF_NEED_RESCHED handling

Pull third pile of VFS updates from Al Viro:
 "Stuff from Jeff Layton, mostly.  Sanitizing interplay between audit
  and namei, removing a lot of insanity from audit_inode() mess and
  getting things ready for his ESTALE patchset."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  procfs: don't need a PATH_MAX allocation to hold a string representation of an int
  vfs: embed struct filename inside of names_cache allocation if possible
  audit: make audit_inode take struct filename
  vfs: make path_openat take a struct filename pointer
  vfs: turn do_path_lookup into wrapper around struct filename variant
  audit: allow audit code to satisfy getname requests from its names_list
  vfs: define struct filename and have getname() return it
  vfs: unexport getname and putname symbols
  acct: constify the name arg to acct_on
  vfs: allocate page instead of names_cache buffer in mount_block_root
  audit: overhaul __audit_inode_child to accomodate retrying
  audit: optimize audit_compare_dname_path
  audit: make audit_compare_dname_path use parent_len helper
  audit: remove dirlen argument to audit_compare_dname_path
  audit: set the name_len in audit_inode for parent lookups
  audit: add a new "type" field to audit_names struct
  audit: reverse arguments to audit_inode_child
  audit: no need to walk list in audit_inode if name is NULL
  audit: pass in dentry to audit_copy_inode wherever possible
  audit: remove unnecessary NULL ptr checks from do_path_lookup

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

In the common case where a name is much smaller than PATH_MAX, an extra
allocation for struct filename is unnecessary. Before allocating a
separate one, try to embed the struct filename inside the buffer first. If
it turns out that that's not long enough, then fall back to allocating a
separate struct filename and redoing the copy.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Keep a pointer to the audit_names "slot" in struct filename.

Have all of the audit_inode callers pass a struct filename ponter to
audit_inode instead of a string pointer. If the aname field is already
populated, then we can skip walking the list altogether and just use it
directly.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

...and fix up the callers. For do_file_open_root, just declare a
struct filename on the stack and fill out the .name field. For
do_filp_open, make it also take a struct filename pointer, and fix up its
callers to call it appropriately.

For filp_open, add a variant that takes a struct filename pointer and turn
filp_open into a wrapper around it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

...and make the user_path callers use that variant instead.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Currently, if we call getname() on a userland string more than once,
we'll get multiple copies of the string and multiple audit_names
records.

Add a function that will allow the audit_names code to satisfy getname
requests using info from the audit_names list, avoiding a new allocation
and audit_names records.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.

For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.

This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.

Later, we'll add other information to the struct as it becomes
convenient.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

All the called functions expect interrupts to be enabled, and
now one of them has started to warn about it, so make it correct.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

UAPI Disintegration 2012-10-09

The device had an undocumented "feature": it can provide a sequence of
spurious link-down status data even if the link is up all the time.
A sequence of 10 was seen so update the link state only after the device
reports the same link state 20 times.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Reported-by: Michael Leun <lkml20120218@newton.leun.net>
Tested-by: Michael Leun <lkml20120218@newton.leun.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

It is not easy to use in4_pton() correctly without reading
its definition, so add some doc for it.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

It is not easy to use in6_pton() correctly without reading
its definition, so add some doc for it.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use be32_to_cpu instead of htonl to keep sparse happy.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

After commit e2446eaa

 ("tcp_v4_send_reset: binding oif to iif in no
sock case").. tcp resets are always lost, when routing is asymmetric.
Yes, backing out that patch will result in misrouting of resets for
dead connections which used interface binding when were alive, but we
actually cannot do anything here.  What's died that's died and correct
handling normal unbound connections is obviously a priority.

Comment to comment:
> This has few benefits:
>   1. tcp_v6_send_reset already did that.

It was done to route resets for IPv6 link local addresses. It was a
mistake to do so for global addresses. The patch fixes this as well.

Actually, the problem appears to be even more serious than guaranteed
loss of resets.  As reported by Sergey Soloviev <sol@eqv.ru>, those
misrouted resets create a lot of arp traffic and huge amount of
unresolved arp entires putting down to knees NAT firewalls which use
asymmetric routing.

Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

* allow kernel_execve() leave the actual return to userland to
caller (selected by CONFIG_GENERIC_KERNEL_EXECVE).  Callers
updated accordingly.
* architecture that does select GENERIC_KERNEL_EXECVE in its
Kconfig should have its ret_from_kernel_thread() do this:
	call schedule_tail
	call the callback left for it by copy_thread(); if it ever
returns, that's because it has just done successful kernel_execve()
	jump to return from syscall
IOW, its only difference from ret_from_fork() is that it does call the
callback.
* such an architecture should also get rid of ret_from_kernel_execve()
and __ARCH_WANT_KERNEL_EXECVE

This is the last part of infrastructure patches in that area - from
that point on work on different architectures can live independently.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Merge tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen fixes from Konrad Rzeszutek Wilk:
 "This has four bug-fixes and one tiny feature that I forgot to put
  initially in my tree due to oversight.

  The feature is for kdump kernels to speed up the /proc/vmcore reading.
  There is a ram_is_pfn helper function that the different platforms can
  register for.  We are now doing that.

  The bug-fixes cover some embarrassing struct pv_cpu_ops variables
  being set to NULL on Xen (but not baremetal).  We had a similar issue
  in the past with {write|read}_msr_safe and this fills the three
  missing ones.  The other bug-fix is to make the console output (hvc)
  be capable of dealing with misbehaving backends and not fall flat on
  its face.  Lastly, a quirk for older XenBus implementations that came
  with an ancient v3.4 hypervisor (so RHEL5 based) - reading of certain
  non-existent attributes just hangs the guest during bootup - so we
  take precaution of not doing that on such older installations.

  Feature:
   - Register a pfn_is_ram helper to speed up reading of /proc/vmcore.
  Bug-fixes:
   - Three pvops call for Xen were undefined causing BUG_ONs.
   - Add a quirk so that the shutdown watches (used by kdump) are not
     used with older Xen (3.4).
   - Fix ungraceful state transition for the HVC console."

* tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches.
  xen/bootup: allow {read|write}_cr8 pvops call.
  xen/bootup: allow read_tscp call for Xen PV guests.
  xen pv-on-hvm: add pfn_is_ram helper for kdump
  xen/hvc: handle backend CLOSED without CLOSING

Pull SLAB fix from Pekka Enberg:
 "This contains a lockdep false positive fix from Jiri Kosina I missed
  from the previous pull request."

* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  mm, slab: release slab_mutex earlier in kmem_cache_destroy()

Pull timer core update from Thomas Gleixner:
 - Bug fixes (one for a longstanding dead loop issue)
 - Rework of time related vsyscalls
 - Alarm timer updates
 - Jiffies updates to remove compile time dependencies

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Cast raw_interval to u64 to avoid shift overflow
  timers: Fix endless looping between cascade() and internal_add_timer()
  time/jiffies: bring back unconditional LATCH definition
  time: Convert x86_64 to using new update_vsyscall
  time: Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems
  time: Introduce new GENERIC_TIME_VSYSCALL
  time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD
  time: Move update_vsyscall definitions to timekeeper_internal.h
  time: Move timekeeper structure to timekeeper_internal.h for vsyscall changes
  jiffies: Remove compile time assumptions about CLOCK_TICK_RATE
  jiffies: Kill unused TICK_USEC_TO_NSEC
  alarmtimer: Rename alarmtimer_remove to alarmtimer_dequeue
  alarmtimer: Remove unused helpers & defines
  alarmtimer: Use hrtimer per-alarm instead of per-base
  alarmtimer: Implement minimum alarm interval for allowing suspend

Pull scheduler fixes from Ingo Molnar:
 "A CPU hotplug related crash fix and a nohz accounting fixlet."

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Update sched_domains_numa_masks[][] when new cpus are onlined
  sched: Ensure 'sched_domains_numa_levels' is safe to use in other functions
  nohz: Fix one jiffy count too far in idle cputime

Pull RCU fixes from Ingo Molnar:
 "This tree includes a shutdown/cpu-hotplug deadlock fix and a
  documentation fix."

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Advise most users not to enable RCU user mode
  rcu: Grace-period initialization excludes only RCU notifier

The commit 254d1a3f

, titled
"xen/pv-on-hvm kexec: shutdown watches from old kernel" assumes that the
XenBus backend can deal with reading of values from:
 "control/platform-feature-xs_reset_watches":

    ... a patch for xenstored is required so that it
    accepts the XS_RESET_WATCHES request from a client (see changeset
    23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored
    the registration of watches will fail and some features of a PVonHVM
    guest are not available. The guest is still able to boot, but repeated
    kexec boots will fail."

Sadly this is not true when using a Xen 3.4 hypervisor and booting a PVHVM
guest. We end up hanging at:

  err = xenbus_scanf(XBT_NIL, "control",
                        "platform-feature-xs_reset_watches", "%d", &supported);

This can easily be seen with guests hanging at xenbus_init:

NX (Execute Disable) protection: active
SMBIOS 2.4 present.
DMI: Xen HVM domU, BIOS 3.4.0 05/13/2011
Hypervisor detected: Xen HVM
Xen version 3.4.
Xen Platform PCI: I/O protocol version 1
... snip ..
calling  xenbus_init+0x0/0x27e @ 1

Reverting the commit or using the attached patch fixes the issue. This fix
checks whether the hypervisor is older than 4.0 and if so does not try to
perform the read.

Fixes-Oracle-Bug: 14708233
CC: stable@vger.kernel.org
Acked-by: Olaf Hering <olaf@aepfle.de>
[v2: Added a comment in the source code]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We actually do not do anything about it. Just return a default
value of zero and if the kernel tries to write anything but 0
we BUG_ON.

This fixes the case when an user tries to suspend the machine
and it blows up in save_processor_state b/c 'read_cr8' is set
to NULL and we get:

kernel BUG at /home/konrad/ssd/linux/arch/x86/include/asm/paravirt.h:100!
invalid opcode: 0000 [#1] SMP
Pid: 2687, comm: init.late Tainted: G           O 3.6.0upstream-00002-gac264ac-dirty #4 Bochs Bochs
RIP: e030:[<ffffffff814d5f42>]  [<ffffffff814d5f42>] save_processor_state+0x212/0x270

.. snip..
Call Trace:
 [<ffffffff810733bf>] do_suspend_lowlevel+0xf/0xac
 [<ffffffff8107330c>] ? x86_acpi_suspend_lowlevel+0x10c/0x150
 [<ffffffff81342ee2>] acpi_suspend_enter+0x57/0xd5

CC: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The hypervisor will trap it. However without this patch,
we would crash as the .read_tscp is set to NULL. This patch
fixes it and sets it to the native_read_tscp call.

CC: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

 into core/rcu

Pull RCU fixes from Paul E. McKenney.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

I see no callers in module code.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>