Commit 4104d326 "ftrace: Remove global function list and call
function directly" cleaned up the global_ops filtering and made
the code simpler, but it left a variable "hash_enable" that was used
to know if the hash functions should be updated or not. It was
updated if the global_ops did not override them. As the global_ops
are now no different than any other ftrace_ops, the hash always
gets updated and there's no reason to use the hash_enable boolean.

The same goes for hash_disable used in ftrace_shutdown().
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

There are some code paths in the kernel that need to do some preparations
before it calls a tracepoint. As that code is worthless overhead when
the tracepoint is not enabled, it would be prudent to have that code
only run when the tracepoint is active. To accomplish this, all tracepoints
now get a static inline function called "trace_<tracepoint-name>_enabled()"
which returns true when the tracepoint is enabled and false otherwise.

As an added bonus, that function uses the static_key of the tracepoint
such that no branch is needed.

  if (trace_mytracepoint_enabled()) {
	arg = process_tp_arg();
	trace_mytracepoint(arg);
  }

Will keep the "process_tp_arg()" (which may be expensive to run) from
being executed when the tracepoint isn't enabled.

It's best to encapsulate the tracepoint itself in the if statement
just to keep races. For example, if you had:

  if (trace_mytracepoint_enabled())
	arg = process_tp_arg();
  trace_mytracepoint(arg);

There's a chance that the tracepoint could be enabled just after the
if statement, and arg will be undefined when calling the tracepoint.

Link: http://lkml.kernel.org/r/20140506094407.507b6435@gandalf.local.homeAcked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Replace uses of &__get_cpu_var for address calculation with this_cpu_ptr.

Link: http://lkml.kernel.org/p/alpine.DEB.2.10.1404291415560.18364@gentwo.orgAcked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

It has been a while since I last sent a tracing patch. I always keep an
eye on tracing evolutions and contributions in general but given
how busy I am with nohz, isolation and more generally core cleanups stuff,
I seldom have time left to provide deep reviews of tracing patches nor
simply for reviews to begin with.

I've been very lucky to start kernel development on a very young subsystem
with tons of low hanging fruits back in 2008. Given that it deals with
a lot of tricky stuffs all around (sched, timers, irq, preemption, NMIs,
SMP, RCU, ....) I basically learned everything there.

Steve has been doing most of the incredible work these last years.
Thanks a lot!

Of course consider me always available to help on tracing if any hard
days happen.

Link: http://lkml.kernel.org/p/1399131991-13216-1-git-send-email-fweisbec@gmail.com

Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Commit 4104d326 "ftrace: Remove global function list and call
function directly" cleaned up the global_ops filtering and made
the code simpler. But it left out function graph filtering which
also depended on that code. The function graph filtering still
needs to use global_ops as the filter otherwise it wont filter
at all.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Now that the ring buffer has a built in way to wake up readers
when there's data, using irq_work such that it is safe to do it
in any context. But it was still using the old "poor man's"
wait polling that checks every 1/10 of a second to see if it
should wake up a waiter. This makes the latency for a wake up
excruciatingly long. No need to do that anymore.

Completely remove the different wait_poll types from the tracers
and have them all use the default one now.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

When reading from trace_pipe, if tracing is off but nothing was read
it should block. If something is read and tracing is off, then EOF
is returned. If tracing is on and there's nothing to read, it will block.

But because the check of whether tracing is off and something was read
is done after the block on the pipe, it is hit or miss if the EOF is
returned or not leading to inconsistent behavior.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The functions ftrace_set_global_filter() and ftrace_set_global_notrace()
still have their old names in the kernel doc (ftrace_set_filter and
ftrace_set_notrace respectively). Replace these with the real names.

Link: http://lkml.kernel.org/p/1398006644-5935-3-git-send-email-wangjiaxing@insigma.com.cnSigned-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

When using ftrace_ops_list_func, we should skip 4 instead of 3,
to avoid ftrace_call+0x5/0xb appearing in the stack trace:

        Depth    Size   Location    (110 entries)
        -----    ----   --------
  0)     2956       0   update_curr+0xe/0x1e0
  1)     2956      68   ftrace_call+0x5/0xb
  2)     2888      92   enqueue_entity+0x53/0xe80
  3)     2796      80   enqueue_task_fair+0x47/0x7e0
  4)     2716      28   enqueue_task+0x45/0x70
  5)     2688      12   activate_task+0x22/0x30

Add a function using_ftrace_ops_list_func() to test for this while keeping
ftrace_ops_list_func to remain static.

Link: http://lkml.kernel.org/p/1398006644-5935-2-git-send-email-wangjiaxing@insigma.com.cnSigned-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

This patch adds static to the following functions:
-cycle_t buffer_ftrace_now
-void free_snapshot
-int trace_selftest_startup_dynamic_tracing

Link: http://lkml.kernel.org/p/20140417214442.d7abc7c0b0e4b90e7fedecc9@skynet.beSigned-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Instead of initializing the pm notifier block in register_ftrace_graph(),
initialize it statically. This safes us some code.

Found in the PaX patch, written by the PaX Team.

Link: http://lkml.kernel.org/p/1396186310-3156-1-git-send-email-minipli@googlemail.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: PaX Team <pageexec@freemail.hu>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The colon at the end of the printk message suggests that it should get printed
before the details printed by ftrace_bug().

When touching the line, let's use the preferred pr_warn() macro as suggested
by checkpatch.pl.

Link: http://lkml.kernel.org/r/1392650573-3390-5-git-send-email-pmladek@suse.czSigned-off-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The irqsoff, preemptoff and preemptirqsoff tracers can now be used by
instances. But they may only be used by one instance at a time (including
the top level directory). This allows multiple tracers to run while the
irqsoff (and friends) tracer is running simultaneously.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The wakeup and wakeup_rt tracers can now be used by instances.
But they may only be used by one instance at a time (including the
top level directory). This allows multiple tracers to run while
the wakeup tracer is running simultaneously.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

In preparation for having tracers enabled in instances, the max_lock
should be unique as updating the max for one tracer is a separate
operation than updating it for another tracer using a different max.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

In preparation for letting the latency tracers be used by instances,
remove the global tracing_max_latency variable and add a max_latency
field to the trace_array that the latency tracers will now use.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Instead of having a list of global functions that are called,
as only one global function is allow to be enabled at a time, there's
no reason to have a list.

Instead, simply have all the users of the global ops, use the global ops
directly, instead of registering their own ftrace_ops. Just switch what
function is used before enabling the function tracer.

This removes a lot of code as well as the complexity involved with it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Pull slave-dmaengine fixes from Vinod Koul:
 "Back from long weekend here in India and now the time to send fixes
  for slave dmaengine.
   - Dan's fix of sirf xlate code
   - Jean's fix for timberland
   - edma fixes by Sekhar for SG handling and Yuan for changing init
     call"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dma: fix eDMA driver as a subsys_initcall
  dmaengine: sirf: off by one in of_dma_sirfsoc_xlate()
  platform: Fix timberdale dependencies
  dma: edma: fix incorrect SG list handling

Pull iommu fixes from Joerg Roedel:
 "Fixes for regressions:

   - fix wrong IOMMU enumeration causing some SCSI device drivers
     initialization failures
   - ARM-SMMU fixes for a panic condition and a wrong return value"

* tag 'iommu-fixes-v3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/arm-smmu: fix panic in arm_smmu_alloc_init_pte
  iommu/arm-smmu: Return 0 on unmap failure
  iommu/vt-d: fix bug in matching PCI devices with DRHD/RMRR descriptors
  iommu/vt-d: Fix get_domain_for_dev() handling of upstream PCIe bridges
  iommu/vt-d: fix memory leakage caused by commit ea8ea460

Pull perf tooling fixes from Ingo Molnar:
 "Three small tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Improve error reporting
  perf tools: Adjust symbols in VDSO
  perf kvm: Fix 'Min time' counting in report command

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf into perf/urgent

Pull perf/urgent fixes from Jiri Olsa:

User visible changes:

  * Adjust symbols in VDSO to properly resolve its function names (Vladimir Nikulichev)

  * Improve error reporting for record session failure (Adrien BAK)

  * Fix 'Min time' counting in report command (Alexander Yarygin)
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

In the current version, when using perf record, if something goes
wrong in tools/perf/builtin-record.c:375
  session = perf_session__new(file, false, NULL);

The error message:
"Not enough memory for reading per file header"

is issued. This error message seems to be outdated and is not very
helpful. This patch proposes to replace this error message by
"Perf session creation failed"

I believe this issue has been brought to lkml:
https://lkml.org/lkml/2014/2/24/458
although this patch only tackles a (small) part of the issue.

Additionnaly, this patch improves error reporting in
tools/perf/util/data.c open_file_write.

Currently, if the call to open fails, the user is unaware of it.
This patch logs the error, before returning the error code to
the caller.
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Adrien BAK <adrien.bak@metascale.org>
Link: http://lkml.kernel.org/r/1397786443.3093.4.camel@beast
[ Reorganize the changelog into paragraphs ]
[ Added empty line after fd declaration in open_file_write ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>

pert-report doesn't resolve function names in VDSO:

$ perf report --stdio -g flat,0.0,15,callee --sort pid
...
            8.76%
               0x7fff6b1fe861
               __gettimeofday
               ACE_OS::gettimeofday()
...

In this case symbol values should be adjusted the same way as for executables,
relocatable objects and prelinked libraries.

After fix:

$ perf report --stdio -g flat,0.0,15,callee --sort pid
...
            8.76%
               __vdso_gettimeofday
               __gettimeofday
               ACE_OS::gettimeofday()
Signed-off-by: Vladimir Nikulichev <nvs@tbricks.com>
Tested-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/r/969812.163009436-sendEmail@nvsSigned-off-by: Jiri Olsa <jolsa@redhat.com>

Every event in the perf-kvm has a 'stats' structure, which contains
max/min/average/etc times of handling this event.
The problem is that the 'perf-kvm stat report' command always shows
that 'min time' is 0us for every event. Example:

 # perf kvm stat report

 Analyze events for all VCPUs:

    VM-EXIT    Samples  Samples%     Time%   Min Time   Max Time Avg time
  [..]
  0xB2 MSCH         12     0.07%     0.00%        0us        8us 7.31us ( +-   2.11% )
  0xB2 CHSC         12     0.07%     0.00%        0us       18us 9.39us ( +-   9.49% )
  0xB2 STPX          8     0.05%     0.00%        0us        2us 1.88us ( +-   7.18% )
  0xB2 STSI          7     0.04%     0.00%        0us       44us 16.49us ( +-  38.20% )
  [..]

This happens because the 'stats' structure is not initialized and
stats->min equals to 0. Lets initialize the structure for every
event after its allocation using init_stats() function. This initializes
stats->min to -1 and makes 'Min time' statistics counting work:

 # perf kvm stat report

 Analyze events for all VCPUs:

    VM-EXIT    Samples  Samples%     Time%   Min Time   Max Time Avg time
  [..]
  0xB2 MSCH         12     0.07%     0.00%        6us        8us 7.31us ( +-   2.11% )
  0xB2 CHSC         12     0.07%     0.00%        7us       18us 9.39us ( +-   9.49% )
  0xB2 STPX          8     0.05%     0.00%        1us        2us 1.88us ( +-   7.18% )
  0xB2 STSI          7     0.04%     0.00%        1us       44us 16.49us ( +-  38.20% )
  [..]
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1397053319-2130-3-git-send-email-borntraeger@de.ibm.com
[ Fixing the perf examples changelog output ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>

A va_list needs to be copied in case it needs to be used twice.

Thanks to Hugh for debugging this issue, leading to various panics.

Tested:

  lpq84:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern

'produce_core' is simply : main() { *(int *)0 = 1;}

  lpq84:~# ./produce_core
  Segmentation fault (core dumped)
  lpq84:~# dmesg | tail -1
  [  614.352947] Core dump to |/foobar12345 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 (null) pipe failed

Notice the last argument was replaced by a NULL (we were lucky enough to
not crash, but do not try this on your production machine !)

After fix :

  lpq83:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern
  lpq83:~# ./produce_core
  Segmentation fault
  lpq83:~# dmesg | tail -1
  [  740.800441] Core dump to |/foobar12345 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 pipe failed

Fixes: 5fe9d8ca ("coredump: cn_vprintf() has no reason to call vsnprintf() twice")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Diagnosed-by: Hugh Dickins <hughd@google.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull x86 fix from Ingo Molnar:
 "This fixes the preemption-count imbalance crash reported by Owen
  Kibel"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Fix CMCI preemption bugs

Pull scheduler fixes from Ingo Molnar:
 "Two fixes:

   - a SCHED_DEADLINE task selection fix
   - a sched/numa related lockdep splat fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Check for stop task appearance when balancing happens
  sched/numa: Fix task_numa_free() lockdep splat

Pull perf fixes from Ingo Molnar:
 "Two kernel side fixes:

   - an Intel uncore PMU driver potential crash fix
   - a kprobes/perf-call-graph interaction fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Use rdmsrl_safe() when initializing RAPL PMU
  kprobes/x86: Fix page-fault handling logic

Pull drm fixes from Dave Airlie:
 "Unfortunately this contains no easter eggs, its a bit larger than I'd
  like, but I included a patch that just moves code from one file to
  another and I'd like to avoid merge conflicts with that later, so it
  makes it seem worse than it is,

  Otherwise:
   - radeon: fixes to use new microcode to stabilise some cards, use
     some common displayport code, some runtime pm fixes, pll regression
     fixes
   - i915: fix for some context oopses, a warn in a used path, backlight
     fixes
   - nouveau: regression fix
   - omap: a bunch of fixes"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (51 commits)
  drm: bochs: drop unused struct fields
  drm: bochs: add power management support
  drm: cirrus: add power management support
  drm: Split out drm_probe_helper.c from drm_crtc_helper.c
  drm/plane-helper: Don't fake-implement primary plane disabling
  drm/ast: fix value check in cbr_scan2
  drm/nouveau/bios: fix a bit shift error introduced by 457e77b2
  drm/radeon/ci: make sure mc ucode is loaded before checking the size
  drm/radeon/si: make sure mc ucode is loaded before checking the size
  drm/radeon: improve PLL params if we don't match exactly v2
  drm/radeon: memory leak on bo reservation failure. v2
  drm/radeon: fix VCE fence command
  drm/radeon: re-enable mclk dpm on R7 260X asics
  drm/radeon: add support for newer mc ucode on CI (v2)
  drm/radeon: add support for newer mc ucode on SI (v2)
  drm/radeon: apply more strict limits for PLL params v2
  drm/radeon: update CI DPM powertune settings
  drm/radeon: fix runpm handling on APUs (v4)
  drm/radeon: disable mclk dpm on R7 260X
  drm/tegra: Remove gratuitous pad field
  ...

Some i2c fixes over DisplayPort.

* 'drm-next-3.15-wip' of git://people.freedesktop.org/~deathsimple/linux:
  drm/radeon: Improve vramlimit module param documentation
  drm/radeon: fix audio pin counts for DCE6+ (v2)
  drm/radeon/dp: switch to the common i2c over aux code
  drm/dp/i2c: Update comments about common i2c over dp assumptions (v3)
  drm/dp/i2c: send bare addresses to properly reset i2c connections (v4)
  drm/radeon/dp: handle zero sized i2c over aux transactions (v2)
  drm/i915: support address only i2c-over-aux transactions
  drm/tegra: dp: Support address-only I2C-over-AUX transactions

Pull more networking fixes from David Miller:

 1) Fix mlx4_en_netpoll implementation, it needs to schedule a NAPI
    context, not synchronize it.  From Chris Mason.

 2) Ipv4 flow input interface should never be zero, it should be
    LOOPBACK_IFINDEX instead.  From Cong Wang and Julian Anastasov.

 3) Properly configure MAC to PHY connection in mvneta devices, from
    Thomas Petazzoni.

 4) sys_recv should use SYSCALL_DEFINE.  From Jan Glauber.

 5) Tunnel driver ioctls do not use the correct namespace, fix from
    Nicolas Dichtel.

 6) Fix memory leak on seccomp filter attach, from Kees Cook.

 7) Fix lockdep warning for nested vlans, from Ding Tianhong.

 8) Crashes can happen in SCTP due to how the auth_enable value is
    managed, fix from Vlad Yasevich.

 9) Wireless fixes from John W Linville and co.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (45 commits)
  net: sctp: cache auth_enable per endpoint
  tg3: update rx_jumbo_pending ring param only when jumbo frames are enabled
  vlan: Fix lockdep warning when vlan dev handle notification
  seccomp: fix memory leak on filter attach
  isdn: icn: buffer overflow in icn_command()
  ip6_tunnel: use the right netns in ioctl handler
  sit: use the right netns in ioctl handler
  ip_tunnel: use the right netns in ioctl handler
  net: use SYSCALL_DEFINEx for sys_recv
  net: mdio-gpio: Add support for separate MDI and MDO gpio pins
  net: mdio-gpio: Add support for active low gpio pins
  net: mdio-gpio: Use devm_ functions where possible
  ipv4, route: pass 0 instead of LOOPBACK_IFINDEX to fib_validate_source()
  ipv4, fib: pass LOOPBACK_IFINDEX instead of 0 to flowi4_iif
  mlx4_en: don't use napi_synchronize inside mlx4_en_netpoll
  net: mvneta: properly configure the MAC <-> PHY connection in all situations
  net: phy: add minimal support for QSGMII PHY
  sfc:On MCDI timeout, issue an FLR (and mark MCDI to fail-fast)
  mwifiex: fix hung task on command timeout
  mwifiex: process event before command response
  ...

Pull cifs fixes from Steve French:
 "A set of 5 small cifs fixes"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cif: fix dead code
  cifs: fix error handling cifs_user_readv
  fs: cifs: remove unused variable.
  Return correct error on query of xattr on file with empty xattrs
  cifs: Wait for writebacks to complete before attempting write.

Pull char/misc driver fixes from Greg KH:
 "Here are a few driver fixes for char/misc drivers that resolve
  reported issues.

  All have been in linux-next successfully for a few days"

* tag 'char-misc-3.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  Drivers: hv: vmbus: Negotiate version 3.0 when running on ws2012r2 hosts
  Tools: hv: Handle the case when the target file exists correctly
  vme_tsi148: Utilize to_pci_dev() macro
  vme_tsi148: Fix PCI address mapping assumption
  vme_tsi148: Fix typo in tsi148_slave_get()
  w1: avoid recursive device_add
  w1: fix netlink refcnt leak on error path
  misc: Grammar s/addition/additional/
  drivers: mcb: fix memory leak in chameleon_parse_cells() error path
  mei: ignore client writing state during cb completion
  mei: me: do not load the driver if the FW doesn't support MEI interface
  GenWQE: Increase driver version number
  GenWQE: Fix multithreading problems
  GenWQE: Ensure rc is not returning an uninitialized value
  GenWQE: Add wmb before DDCB is started
  GenWQE: Enable access to VPD flash area

Merge tag 'driver-core-3.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are some driver core fixes for 3.15-rc2.  Also in here are some
  documentation updates, as well as an API removal that had to wait for
  after -rc1 due to the cleanups coming into you from multiple developer
  trees (this one and the PPC tree.)

  All have been in linux next successfully"

* tag 'driver-core-3.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  drivers/base/dd.c incorrect pr_debug() parameters
  Documentation: Update stable address in Chinese and Japanese translations
  topology: Fix compilation warning when not in SMP
  Chinese: add translation of io_ordering.txt
  stable_kernel_rules: spelling/word usage
  sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()
  kernfs: protect lazy kernfs_iattrs allocation with mutex
  fs: Don't return 0 from get_anon_bdev

Pull staging driver fixes from Greg KH:
 "Here are a few staging driver fixes for issues that have been reported
  for 3.15-rc2.

  Also dominating the diffstat for the pull request is the removal of
  the rtl8187se driver.  It's no longer needed in staging as a "real"
  driver for this hardware is now merged in the tree in the "correct"
  location in drivers/net/

  All of these patches have been tested in linux-next"

* tag 'staging-3.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: r8188eu: Fix case where ethtype was never obtained and always be checked against 0
  staging: r8712u: Fix case where ethtype was never obtained and always be checked against 0
  staging: r8188eu: Calling rtw_get_stainfo() with a NULL sta_addr will return NULL
  staging: comedi: fix circular locking dependency in comedi_mmap()
  staging: r8723au: Add missing initialization of change_inx in sort algorithm
  Staging: unisys: use after free in list_for_each()
  staging: unisys: use after free in error messages
  staging: speakup: fix misuse of kstrtol() in handle_goto()
  staging: goldfish: Call free_irq in error path
  staging: delete rtl8187se wireless driver
  staging: rtl8723au: Fix buffer overflow in rtw_get_wfd_ie()
  staging: gs_fpgaboot: remove __TIMESTAMP__ macro
  staging: vme: fix memory leak in vme_user_probe()
  staging: fpgaboot: clean up Makefile
  staging/usbip: fix store_attach() sscanf return value check
  staging/usbip: userspace - fix usbipd SIGSEGV from refresh_exported_devices()
  staging: rtl8188eu: remove spaces, correct counts to unbreak P2P ioctls
  staging/rtl8821ae: Fix OOM handling in _rtl_init_deferred_work()

Pull tty/serial driver fixes from Greg KH:
 "Here are a number of small tty/serial driver fixes for 3.15-rc2.  Also
  in here are some Documentation file removals for drivers that we
  removed a long time ago, no need to keep it around any longer.

  All of these have been in linux-next for a bit"

* tag 'tty-3.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "serial: 8250, disable "too much work" messages"
  serial: amba-pl011: fix regression, causing an Oops on rmmod
  tty: Fix help text of SYNCLINK_CS
  tty: fix memleak in alloc_pid
  ttyprintk: Allow built as a module
  ttyprintk: Fix wrong tty_unregister_driver() call in the error path
  serial: 8250, disable "too much work" messages
  Documentation/serial: Delete obsolete driver documentation
  serial: omap: Fix missing pm_runtime_resume handling by simplifying code
  serial_core: Fix pm imbalance on unbind
  serial: pl011: change Rx burst size to half of trigger level
  serial: timberdale: Depend on X86_32
  serial: st-asc: Fix SysRq char handling
  Revert "serial: clps711x: Give a chance to perform useful tasks during wait loop"
  serial_core: Fix conditional start_tx on ring buffer not empty
  serial: efm32: use $vendor,$device scheme for compatible string
  serial: omap: free the wakeup settings in remove

Pull USB fixes from Greg KH:
 "Here are a number of tiny USB fixes and new device ids for 3.15-rc2.
  Nothing major, just issues some people have reported.

  All of these have been in linux-next"

* tag 'usb-3.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  uas: fix deadlocky memory allocations
  uas: fix error handling during scsi_scan()
  uas: fix GFP_NOIO under spinlock
  uwb: adds missing error handling
  USB: cdc-acm: Remove Motorola/Telit H24 serial interfaces from ACM driver
  USB: ohci-jz4740: FEAT_POWER is a port feature, not a hub feature
  USB: ohci-jz4740: Fix uninitialized variable warning
  USB: EHCI: tegra: set txfill_tuning
  usb: ehci-platform: Return immediately from suspend if ehci_suspend fails
  usb: ehci-exynos: Return immediately from suspend if ehci_suspend fails
  USB: fix crash during hotplug of PCI USB controller card
  USB: cdc-acm: fix double usb_autopm_put_interface() in acm_port_activate()
  usb: usb-common: fix typo for usb_state_string
  USB: usb_wwan: fix handling of missing bulk endpoints
  USB: pl2303: add ids for Hewlett-Packard HP POS pole displays
  USB: cp210x: Add 8281 (Nanotec Plug & Drive)
  usb: option driver, add support for Telit UE910v2
  Revert "USB: serial: add usbid for dell wwan card to sierra.c"
  USB: serial: ftdi_sio: add id for Brainboxes serial cards

Merge misc fixes from Andrew Morton:
 "13 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  thp: close race between split and zap huge pages
  mm: fix new kernel-doc warning in filemap.c
  mm: fix CONFIG_DEBUG_VM_RB description
  mm: use paravirt friendly ops for NUMA hinting ptes
  mips: export flush_icache_range
  mm/hugetlb.c: add cond_resched_lock() in return_unused_surplus_pages()
  wait: explain the shadowing and type inconsistencies
  Shiraz has moved
  Documentation/vm/numa_memory_policy.txt: fix wrong document in numa_memory_policy.txt
  powerpc/mm: fix ".__node_distance" undefined
  kernel/watchdog.c:touch_softlockup_watchdog(): use raw_cpu_write()
  init/Kconfig: move the trusted keyring config option to general setup
  vmscan: reclaim_clean_pages_from_list() must use mod_zone_page_state()

Sasha Levin has reported two THP BUGs[1][2].  I believe both of them
have the same root cause.  Let's look to them one by one.

The first bug[1] is "kernel BUG at mm/huge_memory.c:1829!".  It's
BUG_ON(mapcount != page_mapcount(page)) in __split_huge_page().  From my
testing I see that page_mapcount() is higher than mapcount here.

I think it happens due to race between zap_huge_pmd() and
page_check_address_pmd().  page_check_address_pmd() misses PMD which is
under zap:

	CPU0						CPU1
						zap_huge_pmd()
						  pmdp_get_and_clear()
__split_huge_page()
  anon_vma_interval_tree_foreach()
    __split_huge_page_splitting()
      page_check_address_pmd()
        mm_find_pmd()
	  /*
	   * We check if PMD present without taking ptl: no
	   * serialization against zap_huge_pmd(). We miss this PMD,
	   * it's not accounted to 'mapcount' in __split_huge_page().
	   */
	  pmd_present(pmd) == 0

  BUG_ON(mapcount != page_mapcount(page)) // CRASH!!!

						  page_remove_rmap(page)
						    atomic_add_negative(-1, &page->_mapcount)

The second bug[2] is "kernel BUG at mm/huge_memory.c:1371!".
It's VM_BUG_ON_PAGE(!PageHead(page), page) in zap_huge_pmd().

This happens in similar way:

	CPU0						CPU1
						zap_huge_pmd()
						  pmdp_get_and_clear()
						  page_remove_rmap(page)
						    atomic_add_negative(-1, &page->_mapcount)
__split_huge_page()
  anon_vma_interval_tree_foreach()
    __split_huge_page_splitting()
      page_check_address_pmd()
        mm_find_pmd()
	  pmd_present(pmd) == 0	/* The same comment as above */
  /*
   * No crash this time since we already decremented page->_mapcount in
   * zap_huge_pmd().
   */
  BUG_ON(mapcount != page_mapcount(page))

  /*
   * We split the compound page here into small pages without
   * serialization against zap_huge_pmd()
   */
  __split_huge_page_refcount()
						VM_BUG_ON_PAGE(!PageHead(page), page); // CRASH!!!

So my understanding the problem is pmd_present() check in mm_find_pmd()
without taking page table lock.

The bug was introduced by me commit with commit 117b0791. Sorry for
that. :(

Let's open code mm_find_pmd() in page_check_address_pmd() and do the
check under page table lock.

Note that __page_check_address() does the same for PTE entires
if sync != 0.

I've stress tested split and zap code paths for 36+ hours by now and
don't see crashes with the patch applied. Before it took <20 min to
trigger the first bug and few hours for second one (if we ignore
first).

[1] https://lkml.kernel.org/g/<53440991.9090001@oracle.com>
[2] https://lkml.kernel.org/g/<5310C56C.60709@oracle.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>	[3.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>