The current method of printing out a stack trace is to add a new line
and print out the trace:

    yum-updatesd-3120  [002]   573.691303:
 => do_softirq
 => irq_exit
 => smp_apic_timer_interrupt
 => apic_timer_interrupt

This looks a bit awkward, and if we have both stack and user stack traces
running, it would be nice to have a title to tell them apart, although
it is easy to tell by the output.

This patch adds an annotation to the start of the stack traces:

            init-1     [003]   929.304979: <stack trace>
 => user_path_at
 => vfs_fstatat
 => vfs_stat
 => sys_newstat
 => system_call_fastpath

             cat-3459  [002]  1016.824040: <user stack trace>
 =>  <0000003aae6c0250>
 =>  <00007ffff4b06ae4>
 =>  <69636172742f6775>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Here is an updated patch to include the extra call to
trace_seq_init() as requested. This is vs. the latest
-tip tree and fixes the use of multiple __print_flags
and __print_symbolic in a single tracer. Also tested
to ensure its working now:

mount.gfs2-2534  [000]   235.850587: gfs2_glock_queue: 8.7 glock 1:2 dequeue PR
mount.gfs2-2534  [000]   235.850591: gfs2_demote_rq: 8.7 glock 1:0 demote EX to NL flags:DI
mount.gfs2-2534  [000]   235.850591: gfs2_glock_queue: 8.7 glock 1:0 dequeue EX
glock_workqueue-2529  [000]   235.850666: gfs2_glock_state_change: 8.7 glock 1:0 state EX => NL tgt:NL dmt:NL flags:lDpI
glock_workqueue-2529  [000]   235.850672: gfs2_glock_put: 8.7 glock 1:0 state NL => IV flags:I
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
LKML-Reference: <1244037123.29604.603.camel@localhost.localdomain>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

According to "events/ftrace/user_stack/format", fix the output of
user stack.

before fix:

  sh-1073  [000]    31.137561:  <b7f274fe> <-  <0804e33c> <-  <080835c1>

after fix:

  sh-1072  [000]    37.039329:
 =>  <b7f8a4fe>
 =>  <0804e33c>
 =>  <080835c1>
Signed-off-by: Nwalimis <walimisdev@gmail.com>
LKML-Reference: <1244016090-7814-3-git-send-email-walimisdev@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

According to "events/ftrace/kernel_stack/format", output format of
kernel stack should use "=>" instead of "<=".

The second problem is that we shouldn't skip the first entry in the stack,
although it seems to be duplicated when used in the "function" tracer,
but events also use it. If we skip the first one, we will drop the topmost
entry of the stack.

The last problem is that if the last entry is ULONG_MAX(0xffffffff), we should
drop it, otherwise it will print a NULL name line.

before fix:

      sh-1072  [000]   26.957239: sched_process_fork: parent sh:1072 child sh:1073
      sh-1072  [000]   26.957262:
 <= syscall_call
 <=
      sh-1072  [000]   26.957744: sched_switch: task sh:1072 [120] (R) ==> sh:1073 [120]
      sh-1072  [000]   26.957752:
 <= preempt_schedule
 <= wake_up_new_task
 <= do_fork
 <= sys_clone
 <= syscall_call
 <=

After fix:

      sh-1075  [000]    39.791848: sched_process_fork: parent sh:1075  child sh:1076
      sh-1075  [000]    39.791871:
 => sys_clone
 => syscall_call
      sh-1075  [000]    39.792713: sched_switch: task sh:1075 [120] (R) ==> sh:1076 [120]
      sh-1075  [000]    39.792722:
 => schedule
 => preempt_schedule
 => wake_up_new_task
 => do_fork
 => sys_clone
 => syscall_call
Signed-off-by: Nwalimis <walimisdev@gmail.com>
LKML-Reference: <1244016090-7814-2-git-send-email-walimisdev@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The last entry in the stack_dump_trace is ULONG_MAX, which is not
a valid entry, but max_stack_trace.nr_entries has accounted for it.
So when printing the header, we should decrease it by one.
Before fix, print as following, for example:

	Depth    Size   Location    (53 entries)	<--- should be 52
	-----    ----   --------
  0)     3264     108   update_wall_time+0x4d5/0x9a0
  ...
 51)       80      80   syscall_call+0x7/0xb
 ^^^
   it's correct.
Signed-off-by: Nwalimis <walimisdev@gmail.com>
LKML-Reference: <1244016090-7814-1-git-send-email-walimisdev@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Every buffer page in the ring buffer includes its own time stamp.
When an event is recorded to the ring buffer with a delta time greater
than what can be held in the event header, a time stamp event is created.

If the the create timestamp falls over to the next buffer page, it is
redundant because the buffer page holds a full time stamp. This patch
will try to discard the time stamp when it falls to the start of the
next page.

This change also fixes a issues with disarding events. If most events are
discarded, timestamps will start to creep into the ring buffer. If we
do not discard the timestamps then they can fill up the ring buffer over
time and waste space.

This change will keep time stamps from filling up over another page. If
something is recorded in the buffer page, and the rest is filtered, then
the time stamps can only fill up to the end of the page.

[ Impact: prevent time stamps from filling ring buffer ]
Reported-by: NTim Bird <tim.bird@am.sony.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

There are times that a race may happen that we add a timestamp in a
nested write. This timestamp would just contain a zero delta and serves
no purpose.

Now that we have a way to discard events, this patch will try to discard
the timestamp instead of just wasting the space in the ring buffer.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

There's a bug in ring_buffer_discard_commit.  The wrong
pointer is being compared in order to check if the event
can be freed from the buffer rather than discarded
(i.e. marked as PAD).

I noticed this when I was working on duration filtering.
The bug is not deadly - it just results in lots of wasted
space in the buffer.  All filtered events are left in
the buffer and marked as discarded, rather than being
removed from the buffer to make space for other events.

Unfortunately, when I fixed this bug, I got errors doing a
filtered function trace.  Multiple TIME_EXTEND
events pile up in the buffer, and trigger the
following loop overage warning in rb_iter_peek():

again:
	...
	if (RB_WARN_ON(cpu_buffer, ++nr_loops > 10))
		return NULL;

I'm not sure what the best way is to fix this. I don't
know if I should extend the loop threshhold, or if I should
make the test more complex (ignore TIME_EXTEND
events), or just get rid of this loop check completely.

Note that if I implement a workaround for this, then I
see another problem from rb_advance_iter().  I haven't
tracked that one down yet.

In general, it seems like the case of removing filtered
events has not been working properly, and so some assumptions
about buffer invariant conditions need to be revisited.

Here's the patch for the simple fix:

Compare correct pointer for checking if an event can be
freed rather than left as discarded in the buffer.
Signed-off-by: NTim Bird <tim.bird@am.sony.com>
LKML-Reference: <4A25BE9E.5090909@am.sony.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

A race was found that if one were to enable and disable the function
profiler repeatedly, then the system can panic. This was because a profiled
function may be preempted just before disabling interrupts. While
the profiler is disabled and then reenabled, the preempted function
could start again, and access the hash as it is being initialized.

This just adds a check in the irq disabled part to check if the profiler
is enabled, and if it is not then it will just exit.

When the system is disabled, the profile_enabled variable is cleared
before calling the unregistering of the function profiler. This
unregistering calls stop machine which also acts as a synchronize schedule.

[ Impact: fix panic in enabling/disabling function profiler ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The trace_pipe did not recognize the latency format flag and would produce
different output than the trace file. The problem was partly due that
the trace flags in the iterator was not set as well as the trace_pipe
zeros out part of the iterator (including the flags) to be able to use
the same routines as the trace file. trace_flags of the iterator should
not cause any problems when not zeroed out by for trace_pipe.
Reported-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

After converting the softirq tracer to use te flags options, this
caused a regression with the name. Since the flag was used directly
it was printed out (i.e. HRTIMER_SOFTIRQ).

This patch only shows the softirq name without the SOFTIRQ part.

[ Impact: fix regression of output from softirq events ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

A patch to allow the use of __print_symbolic and __print_flags
from a module. This allows the current GFS2 tracing patch to
build.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
LKML-Reference: <1243868015.29604.542.camel@localhost.localdomain>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

__string() is limited:

  - it's a char array, but we may want to define array with other types
  - a source string should be available, but we may just know the string size

We introduce __dynamic_array() to break those limitations, and __string()
becomes a wrapper of it. As a side effect, now __get_str() can be used
in TP_fast_assign but not only TP_print.

Take XFS for example, we have the string length in the dirent, but the
string itself is not NULL-terminated, so __dynamic_array() can be used:

TRACE_EVENT(xfs_dir2,
	TP_PROTO(struct xfs_da_args *args),
	TP_ARGS(args),

	TP_STRUCT__entry(
		__field(int, namelen)
		__dynamic_array(char, name, args->namelen + 1)
		...
	),

	TP_fast_assign(
		char *name = __get_str(name);

		if (args->namelen)
			memcpy(name, args->name, args->namelen);
		name[args->namelen] = '\0';

		__entry->namelen = args->namelen;
	),

	TP_printk("name %.*s namelen %d",
		  __entry->namelen ? __get_str(name) : NULL
		  __entry->namelen)
);

[ Impact: allow defining dynamic size arrays ]
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A2384D2.3080403@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Currently TP_fast_assign has a limitation that we can't define local
variables in it.

Here's one use case when we introduce __dynamic_array():

TP_fast_assign(
	type *p = __get_dynamic_array(item);

	foo(p);
	bar(p);
),

[ Impact: allow defining local variables in TP_fast_assign ]
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A2384B1.90100@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

"tsize" should be "\tsize". Also remove the space before "__str_loc".

Before:
 # cat tracing/events/irq/irq_handler_entry/format
        ...
        field:int irq;  offset:12;      size:4;
        field: __str_loc name;  offset:16;tsize:2;
        ...

After:
 # cat tracing/events/irq/irq_handler_entry/format
	...
        field:int irq;  offset:12;      size:4;
        field:__str_loc name;   offset:16;      size:2;
	...

[ Impact: standardize __string field description in events format file ]
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Both event tracer and sched switch plugin are selected by default
by all generic tracers. But if no generic tracer is enabled, their options
appear. But ether one of them will select the other, thus it only
makes sense to have the default tracers be selected by one option.

[ Impact: clean up kconfig menu ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

There are two options that are selected by all tracers, but we want
to have those options available when no tracer is selected. These are

 The event tracer and sched switch tracer.

The are enabled by all tracers, but if a tracer is not selected we want
the options to appear. All tracers including them select TRACING.
Thus what we would like to do is:

  config EVENT_TRACER
	bool "prompt"
	depends on TRACING
	select TRACING

But that gives us a bug in the kbuild system since we just created a
circular dependency. We only want the prompt to show when TRACING is off.

This patch adds GENERIC_TRACER that all tracers will select instead of
TRACING. The two options (sched switch and event tracer) will select
TRACING directly and depend on !GENERIC_TRACER. This solves the cicular
dependency.

[ Impact: hide options that are selected by default ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

When using ftrace=function on the command line to trace functions
on boot up, one can not filter out functions that are commonly called.

This patch adds two new ftrace command line commands.

  ftrace_notrace=function-list
  ftrace_filter=function-list

Where function-list is a comma separated list of functions to filter.
The ftrace_notrace will make the functions listed not be included
in the function tracing, and ftrace_filter will only trace the functions
listed.

These two act the same as the debugfs/tracing/set_ftrace_notrace and
debugfs/tracing/set_ftrace_filter respectively.

The simple glob expressions that are allowed by the filter files can also
be used by the command line interface.

	ftrace_notrace=rcu*,*lock,*spin*

Will not trace any function that starts with rcu, ends with lock, or has
the word spin in it.

Note, if the self tests are enabled, they may interfere with the filtering
set by the command lines.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

"call" is an argument of macro, but it is also used as a local
variable name of function in macro.
We should keep this local variable name distinct from any
CPP macro parameter name if both are in the same macro scope,
although it hasn't caused any problem yet.

[ Impact: robustify macro ]
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

s390 code uses smp_processor_id() in __raw_spin_lock() code which
reveals that a (raw) spinlock is taken without preemption disabled.
This can potentially deadlock.

To fix this explicitly disable and enable preemption.

BUG: using smp_processor_id() in preemptible [00000000] code: cat/2278
caller is trace_find_cmdline+0x40/0xfc
CPU: 0 Not tainted 2.6.30-rc7-dirty #39
Process cat (pid: 2278, task: 000000003faedb68, ksp: 000000003b33b988)
000000003b33b988 000000003b33bae0 0000000000000002 0000000000000000
       000000003b33bb80 000000003b33baf8 000000003b33baf8 00000000000175d6
       0000000000000001 000000003b33b988 000000003f9b0000 000000000000000b
       000000000000000c 000000003b33bb40 000000003b33bae0 0000000000000000
       0000000000000000 00000000000175d6 000000003b33bae0 000000003b33bb28
Call Trace:
([<00000000000174b2>] show_trace+0x112/0x170)
 [<0000000000017582>] show_stack+0x72/0x100
 [<0000000000441538>] dump_stack+0xc8/0xd8
 [<000000000025c350>] debug_smp_processor_id+0x114/0x130
 [<00000000000bf0e4>] trace_find_cmdline+0x40/0xfc
 [<00000000000c35d4>] trace_print_context+0x58/0xac
 [<00000000000bb676>] print_trace_line+0x416/0x470
 [<00000000000bc8fe>] s_show+0x4e/0x428
 [<000000000013834e>] seq_read+0x36a/0x5d4
 [<0000000000112a78>] vfs_read+0xc8/0x174
 [<0000000000112c58>] SyS_read+0x74/0xc4
 [<000000000002c7ae>] sysc_noemu+0x10/0x16
 [<000002000012436c>] 0x2000012436c
1 lock held by cat/2278:
 #0:  (&p->lock){+.+.+.}, at: [<0000000000138056>] seq_read+0x72/0x5d4

[ Impact: fix preempt-unsafe raw spinlock ]
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

The recording of the names at trace time is inefficient. This patch
implements the softirq event recording to only record the vector
and then use the __print_symbolic interface to print out the names.

[ Impact: faster recording of softirq events ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

This patch adds __print_symbolic which is similar to __print_flags but
works for an enumeration type instead. That is, there is only a one to one
mapping between the values and the symbols. When a match is made, then
it is printed, otherwise the hex value is outputed.

[ Impact: add interface for showing symbol names in events ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

This patch changes the output for gfp_flags from being a simple hex value
to the actual names.

  gfp_flags=GFP_ATOMIC  instead of gfp_flags=00000020

And even

  gfp_flags=GFP_KERNEL instead of gfp_flags=000000d0

(Thanks to Frederic Weisbecker for pointing out that the first version
 had a bad order of GFP masks)

[ Impact: more human readable output from tracer ]
Acked-by: NEduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

It is useful to see the state of a task that is being switched out.
This patch adds the output of the state of the previous task in
the context switch event.

[ Impact: see state of switched out task in context switch ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Developers have been asking for the ability in the ftrace event tracer
to display names of bits in a flags variable.

Instead of printing out c2, it would be easier to read FOO|BAR|GOO,
assuming that FOO is bit 1, BAR is bit 6 and GOO is bit 7.

Some examples where this would be useful are the state flags in a context
switch, kmalloc flags, and even permision flags in accessing files.

[
  v2 changes include:

  Frederic Weisbecker's idea of using a mask instead of bits,
  thus we can output GFP_KERNEL instead of GPF_WAIT|GFP_IO|GFP_FS.

  Li Zefan's idea of allowing the caller of __print_flags to add their
  own delimiter (or no delimiter) where we can get for file permissions
  rwx instead of r|w|x.
]

[
  v3 changes:

   Christoph Hellwig's idea of using an array instead of va_args.
]

[ Impact: better displaying of flags in trace output ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Always use ftrace_event_enable_disable() to enable/disable an event
so that we can factorize out the event toggling code.

[ Impact: factorize and cleanup event tracing code ]
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

If we enable a trace event alone without any tracer running (such as
function tracer, sched switch tracer, etc...) it can't output enough
task command information.

We need to use the tracing_{start/stop}_cmdline_record() helpers
which are designed to keep track of cmdlines for any tasks that
were scheduled during the tracing.

Before this patch:
 # echo 1 > debugfs/tracing/events/sched/sched_switch/enable
 # cat debugfs/tracing/trace
 # tracer: nop
 #
 #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
 #              | |       |          |         |
            <...>-2289  [000] 526276.724790: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
            <...>-2287  [000] 526276.725231: sched_switch: task sshd:2287 [120] ==> bash:2289 [120]
            <...>-2289  [000] 526276.725452: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
            <...>-2287  [000] 526276.727181: sched_switch: task sshd:2287 [120] ==> swapper:0 [140]
           <idle>-0     [000] 526277.032734: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
            <...>-5     [000] 526277.032782: sched_switch: task events/0:5 [115] ==> swapper:0 [140]
 ...

After this patch:
 # tracer: nop
 #
 #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
 #              | |       |          |         |
             bash-2269  [000] 527347.989229: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
             sshd-2267  [000] 527347.990960: sched_switch: task sshd:2267 [120] ==> bash:2269 [120]
             bash-2269  [000] 527347.991143: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
             sshd-2267  [000] 527347.992959: sched_switch: task sshd:2267 [120] ==> swapper:0 [140]
           <idle>-0     [000] 527348.531989: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
         events/0-5     [000] 527348.532115: sched_switch: task events/0:5 [115] ==> swapper:0 [140]
 ...

Changelog:
v1->v2: Update Kconfig to select CONTEXT_SWITCH_TRACER in
        ENABLE_EVENT_TRACING
v2->v3: v2 can solve problem that was caused by config EVENT_TRACING
        alone, but when CONFIG_FTRACE is off and CONFIG_TRACING is
        selected by other config, compile fail happened again.
        This version solves it.

[ Impact: fix incomplete output of event tracing ]
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

The kmemtrace.enable kernel parameter no longer works. To enable
kmemtrace at boot-time, you must pass "ftrace=kmemtrace" instead.

[ Impact: remove obsolete kernel parameter documentation ]

Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <alpine.DEB.2.00.0905241112190.10296@rocky>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

When defining a dynamic size string, we add __str_loc_##item to the
trace entry, and it stores the location of the actual string in
entry->_str_data[]

'unsigned short' should be sufficient to store this information, thus
we save 2 bytes per dyn-size string in the ring buffer.

[ Impact: reduce memory occupied by dyn-size strings in ring buffer ]
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A14EDB6.2050507@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

I found that there is nothing to protect event_hash in
ftrace_find_event(). Rcu protects the event hashlist
but not the event itself while we use it after its extraction
through ftrace_find_event().

This lack of a proper locking in this spot opens a race
window between any event dereferencing and module removal.

Eg:

--Task A--

print_trace_line(trace) {
  event = find_ftrace_event(trace)

--Task B--

trace_module_remove_events(mod) {
  list_trace_events_module(ev, mod) {
    unregister_ftrace_event(ev->event) {
      hlist_del(ev->event->node)
        list_del(....)
    }
  }
}
|--> module removed, the event has been dropped

--Task A--

  event->print(trace); // Dereferencing freed memory

If the event retrieved belongs to a module and this module
is concurrently removed, we may end up dereferencing a data
from a freed module.

RCU could solve this, but it would add latency to the kernel and
forbid tracers output callbacks to call any sleepable code.
So this fix converts 'trace_event_mutex' to a read/write semaphore,
and adds trace_event_read_lock() to protect ftrace_find_event().

[ Impact: fix possible freed memory dereference in ftrace ]
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A114806.7090302@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

register_module_notifier() returns zero in the success case.
So fix the inverted fail case check in trace events modules
handler.

[ Impact: fix spurious warning on ftrace initialization]
Reported-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

debugfs directory entries for devices are not removed on some
of the failure pathes in do_blk_trace_setup().
One way to reproduce is to start blktrace on multiple devices
with insufficient Vmalloc space: Devices will fail with
a message like this:

	BLKTRACESETUP(2) /dev/sdu failed: 5/Input/output error

If so, the respective entries in debugfs
(e.g. /sys/kernel/debug/block/sdu) will remain and subsequent
attempts to start blktrace on the respective devices will not
succeed due to existing directories.

[ Impact: fix /debug/tracing file cleanup corner case ]
Signed-off-by: NStefan Raspl <stefan.raspl@linux.vnet.ibm.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: schwidefsky@de.ibm.com
Cc: heiko.carstens@de.ibm.com
LKML-Reference: <4A1266CC.5040801@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- fix some typos
- document the difference between '>' and '>>'
- document the 'enable' toggle
- remove section "Defining an event-enabled tracepoint", since it's
  out-dated and sample/trace_events/ already serves this purpose.

v2: add "Updated by Li Zefan"

[ Impact: make documentation up-to-date ]
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
LKML-Reference: <4A125503.5060406@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

return zero should be correct, so fix it.

[ Impact: eliminate incorrect syslog message ]
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: rostedt@goodmis.org
LKML-Reference: <1242545498-7285-1-git-send-email-tom.leiming@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Merge reason: we were on an -rc4 base, sync up to -rc6
Signed-off-by: NIngo Molnar <mingo@elte.hu>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  PCI MSI: Fix MSI-X with NIU cards
  PCI: Fix pci-e port driver slot_reset bad default return value

* git://git.kernel.org/pub/scm/linux/kernel/git/holtmann/bluetooth-2.6:
  Bluetooth: Don't trigger disconnect timeout for security mode 3 pairing
  Bluetooth: Don't use hci_acl_connect_cancel() for incoming connections
  Bluetooth: Fix wrong module refcount when connection setup fails

Another case of me handling the fallout from Davem's unfortunate
addiction to shuffleboard.

Won't anybody think of the children? Join the anti-shuffleboard league
today!

* 'drm-intel-next' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel:
  drm/i915: Add new GET_PIPE_FROM_CRTC_ID ioctl.
  drm/i915: Set HDMI hot plug interrupt enable for only the output in question.
  drm/i915: Include 965GME pci ID in IS_I965GM(dev) to match UMS.
  drm/i915: Use the GM45 VGA hotplug workaround on G45 as well.
  drm/i915: ignore LVDS on intel graphics systems that lie about having it
  drm/i915: sanity check IER at wait_request time
  drm/i915: workaround IGD i2c bus issue in kernel side (v2)
  drm/i915: Don't allow binding objects into the last page of the aperture.
  drm/i915: save/restore fence registers across suspend/resume
  drm/i915: x86 always has writeq. Add I915_READ64 for symmetry.

* 'upstream-linus' of ssh://master.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  libata: Media rotation rate and form factor heuristics
  libata: Report disk alignment and physical block size
  sata_fsl: Fix the command description of FSL SATA controller
  sata_fsl: Fix compile warnings
  [libata] sata_sx4: fixup interrupt handling
  [libata] sata_sx4: convert to new exception handling methods