The code in stop_machine that modifies the kernel text has a bit
of logic to handle the case of NMIs. stop_machine does not prevent
NMIs from executing, and if an NMI were to trigger on another CPU
as the modifying CPU is changing the NMI text, a GPF could result.

To prevent the GPF, the NMI calls ftrace_nmi_enter() which may
modify the code first, then any other NMIs will just change the
text to the same content which will do no harm. The code that
stop_machine called must wait for NMIs to finish while it changes
each location in the kernel. That code may also change the text
to what the NMI changed it to. The key is that the text will never
change content while another CPU is executing it.

To make the above work, the call to ftrace_nmi_enter() must also
do a smp_mb() as well as atomic_inc().  But for applications like
perf that require a high number of NMIs for profiling, this can have
a dramatic effect on the system. Not only is it doing a full memory
barrier on both nmi_enter() as well as nmi_exit() it is also
modifying a global variable with an atomic operation. This kills
performance on large SMP machines.

Since the memory barriers are only needed when ftrace is in the
process of modifying the text (which is seldom), this patch
adds a "modifying_code" variable that gets set before stop machine
is executed and cleared afterwards.

The NMIs will check this variable and store it in a per CPU
"save_modifying_code" variable that it will use to check if it
needs to do the memory barriers and atomic dec on NMI exit.
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The functions used to implement the TRACE_EVENT macro show up in
function tracing. This is considered a distraction, and these should
not be displayed. For example:

     <idle>-0     [000]    57.202149: task_of <-update_stats_wait_end
     <idle>-0     [000]    57.202149: ftrace_raw_event_sched_stat_wait <-update_stats_wait_end
     <idle>-0     [000]    57.202150: ftrace_raw_event_id_sched_stat_template <-ftrace_raw_event_sched_stat_wait
     <idle>-0     [000]    57.202150: sched_stat_wait: comm=sshd pid=2735 delay=19207 [ns]

The "ftrace_raw_event_*" traces are just the utility functions used
by TRACE_EVENT tracepoints.

Cc: Thomas Gleixner <tglx@linutronix.de>
Requested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

I don't see why we can only clear all functions from the filter.

After patching:

  # echo sys_open > set_graph_function
  # echo sys_close >> set_graph_function
  # cat set_graph_function
  sys_open
  sys_close
  # echo '!sys_close' >> set_graph_function
  # cat set_graph_function
  sys_open
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B726388.2000408@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The branch annotation is a bit difficult to see the worst offenders
because it only sorts by percentage:

 correct incorrect  %        Function                  File              Line
 ------- ---------  -        --------                  ----              ----
       0      163 100 qdisc_restart                  sch_generic.c        179
       0      163 100 pfifo_fast_dequeue             sch_generic.c        447
       0        4 100 pskb_trim_rcsum                skbuff.h             1689
       0        4 100 llc_rcv                        llc_input.c          170
       0       18 100 psmouse_interrupt              psmouse-base.c       304
       0        3 100 atkbd_interrupt                atkbd.c              389
       0        5 100 usb_alloc_dev                  usb.c                437
       0       11 100 vsscanf                        vsprintf.c           1897
       0        2 100 IS_ERR                         err.h                34
       0       23 100 __rmqueue_fallback             page_alloc.c         865
       0        4 100 probe_wakeup_sched_switch      trace_sched_wakeup.c 142
       0        3 100 move_masked_irq                migration.c          11

Adding the incorrect and correct values as sort keys makes this file a
bit more informative:

 correct incorrect  %        Function                  File              Line
 ------- ---------  -        --------                  ----              ----
       0   366541 100 audit_syscall_entry            auditsc.c            1637
       0   366538 100 audit_syscall_exit             auditsc.c            1685
       0   115839 100 sched_info_switch              sched_stats.h        269
       0    74567 100 sched_info_queued              sched_stats.h        222
       0    66578 100 sched_info_dequeued            sched_stats.h        177
       0    15113 100 trace_workqueue_insertion      workqueue.h          38
       0    15107 100 trace_workqueue_execution      workqueue.h          45
       0     3622 100 syscall_trace_leave            ptrace.c             1772
       0     2750 100 sched_move_task                sched.c              10100
       0     2750 100 sched_move_task                sched.c              10110
       0     1815 100 pre_schedule_rt                sched_rt.c           1462
       0      837 100 audit_alloc                    auditsc.c            879
       0      814 100 tcp_mss_split_point            tcp_output.c         1302
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

In the function graph tracer, a calling function is to be traced
only when it is enabled through the set_graph_function file,
or when it is nested in an enabled function.

Current code uses TSK_TRACE_FL_GRAPH to test whether it is nested
or not. Looking at the code, we can get this:
(trace->depth > 0) <==> (TSK_TRACE_FL_GRAPH is set)

trace->depth is more explicit to tell that it is nested.
So we use trace->depth directly and simplify the code.

No functionality is changed.
TSK_TRACE_FL_GRAPH is not removed yet, it is left for future usage.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B4DB0B6.7040607@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Each time we save a function entry from the function graph
tracer, we check if the trace array is set, which is wasteful
because it is set anyway before we start the tracer. All we need
is to ensure we have good read and write orderings. When we set
the trace array, we just need to guarantee it to be visible
before starting tracing.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
LKML-Reference: <1263453795-7496-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If the ftrace stacktrace option is set, then add the stack dumps to
trace_printk.
Requested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Modified recordmcount.pl to use perl constructs that are still
understandable by C hackers that are not perl programmers.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
LKML-Reference: <1262724082-9517-1-git-send-email-w.sang@pengutronix.de>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

- move check for open file in front of the writing loop
- use perl-constructs to access the array
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
LKML-Reference: <1262716072-14414-2-git-send-email-w.sang@pengutronix.de>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

At the beginning, access to the ring buffer was fully serialized
by trace_types_lock. Patch d7350c3f gives more freedom to readers,
and patch b04cc6b1 adds code to protect trace_pipe and cpu#/trace_pipe.

But actually it is not enough, ring buffer readers are not always
read-only, they may consume data.

This patch makes accesses to trace, trace_pipe, trace_pipe_raw
cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized.
And removes tracing_reader_cpumask which is used to protect trace_pipe.

Details:

Ring buffer serializes readers, but it is low level protection.
The validity of the events (which returns by ring_buffer_peek() ..etc)
are not protected by ring buffer.

The content of events may become garbage if we allow another process to consume
these events concurrently:
  A) the page of the consumed events may become a normal page
     (not reader page) in ring buffer, and this page will be rewritten
     by the events producer.
  B) The page of the consumed events may become a page for splice_read,
     and this page will be returned to system.

This patch adds trace_access_lock() and trace_access_unlock() primitives.

These primitives allow multi process access to different cpu ring buffers
concurrently.

These primitives don't distinguish read-only and read-consume access.
Multi read-only access is also serialized.

And we don't use these primitives when we open files,
we only use them when we read files.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B447D52.1050602@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The previous patches added the use of print_fmt string and changes
the trace_define_field() function to also create the fields and
format output for the event format files.

   text	   data	    bss	    dec	    hex	filename
5857201	1355780	9336808	16549789	 fc879d	vmlinux
5884589	1351684	9337896	16574169	 fce6d9	vmlinux-orig

The above shows the size of the vmlinux after this patch set
compared to the vmlinux-orig which is before the patch set.

This saves us 27k on text, 1k on bss and adds just 4k of data.

The total savings of 24k in size.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D4D.40604@cn.fujitsu.com>
Acked-by: NMasami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The calls ftrace_format_##call() and ftrace_define_fields_##call()
are almost duplicate in functionality. With the addition of the
print_fmt in previous patches, these two functions can be merged
into one.

The trace_define_field() defines the fields and links them into
the struct ftrace_event_call. The previous patches introduced
the print_fmt field and this can now be used with the trace_define_field()
to create the event format file fields and print_fmt field.

The struct ftrace_event_call->fields are used to print the fields
The struct ftrace_event_call->print_fmt is used to print
the "print fmt: XXXXXXXXXXX" line.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D49.5000006@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

In the clean up of having all events call one specific function,
the syscall event init was changed to call this helper function.

With the new print_fmt updates, the syscalls need to do special
initializations. This patch converts the syscall events to call
its own init function again.

Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

This is part of a patch set that removes the show_format method
in the ftrace event macros.

Add the print_fmt initialization to the kprobe events.
The print_fmt is still not used, but will be in the follow up
patches.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D45.3080100@cn.fujitsu.com>
Acked-by: NMasami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

This is part of a patch set that removes the show_format method
in the ftrace event macros.

Add the print_fmt initialization to the syscall events.
The print_fmt is still not used, but will be in the follow up
patches.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D41.609@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

This is part of a patch set that removes the show_format method
in the ftrace event macros.

The print_fmt field is added to hold the string that shows
the print_fmt in the event format files. This patch only adds
the field but it is currently not used. Later patches will use
this field to enable us to remove the show_format field
and function.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D3E.2000704@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

This is part of a patch set that removes the show_format method
in the ftrace event macros.

This patch set requires that all fields are added to the
ftrace_event_call->fields. This patch changes __dynamic_array()
to call trace_define_field() to include fields that use __dynamic_array().
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D36.8090100@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc64: Fix Niagara2 perf event handling.
  sparc64: Fix NMI programming when perf events are active.
  bbc_envctrl: Clean up properly if kthread_run() fails.

This reverts commit ae1b22f6.

As Linus said in 982d007a: "There was something really messy about
cmpxchg8b and clone CPU's, so if you enable it on other CPUs later, do it
carefully."

This breaks lguest for those configs, but we can fix that by emulating
if we have to.

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=14884Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
  ocfs2: Handle O_DIRECT when writing to a refcounted cluster.

* 'for-2.6.33' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound-2.6:
  ASoC: fixup oops in generic AC97 codec glue
  ASoC: fix params_rate() macro use in several codecs
  ASoC: fsi-ak4642: Remove ak4642_add_i2c_device

For chips like Niagara2 that have true overflow indications
in the %pcr (which we don't actually need and don't use)
the interrupt signal persists until the overflow bits are
cleared by an explicit %pcr write.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If perf events are active, we should not reset the %pcr to
PCR_PIC_PRIV.  That perf events code does the management.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In bbc_envctrl_init() we have to unlink the fan and temp instances
from the lists because our caller is going to free up the 'bp' object
if we return an error.

We can't rely upon bbc_envctrl_cleanup() to do this work for us in
this case.
Reported-by: NPatrick Finnegan <pat@computer-refuge.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* 'limits_cleanup' of git://decibel.fi.muni.cz/~xslaby/linux:
  resource: add helpers for fetching rlimits
  resource: move kernel function inside __KERNEL__
  SECURITY: selinux, fix update_rlimit_cpu parameter

* 'for-linus/samsung' of git://git.fluff.org/bjdooks/linux:
  ARM: S3C: Fix NAND device registration by s3c_nand_set_platdata().
  ARM: S3C24XX: touchscreen device definition
  ARM: mach-bast: add NAND_SCAN_SILENT_NODEV to optional devices
  ARM: mach-osiris: add NAND_SCAN_SILENT_NODEV to optional devices
  ARM: S3C24XX: touchscreen device definition

Holding locks over device_del -> kobject_del -> sysfs_deactivate can
cause deadlocks if those same locks are grabbed in sysfs show or store
methods.

The I model s_active count + completion as a sleeping read/write lock.
I describe to lockdep sysfs_get_active as a read_trylock,
sysfs_put_active as a read_unlock, and sysfs_deactivate as a
write_lock and write_unlock pair.  This seems to capture the essence
for purposes of finding deadlocks, and in my testing gives finds real
issues and ignores non-issues.

This brings us back to holding locks over kobject_del is a problem
that ideally we should find a way of addressing, but at least lockdep
can tell us about the problems instead of requiring developers to debug
rare strange system deadlocks, that happen when sysfs files are removed
while being written to.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We kill the guest, but then we blatt random stuff.
Reported-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6:
  [S390] Update default configuration.
  [S390] Have param.h simply include <asm-generic/param.h>.
  [S390] qdio: convert global statistics to per-device stats

* 'sh/for-2.6.33' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
  binfmt_elf_fdpic: Fix build breakage introduced by coredump changes.
  sh: update defconfigs.
  sh: Don't default enable PMB support.
  sh: Disable PMB for SH4AL-DSP CPUs.
  sh: Only provide a PCLK definition for legacy CPG CPUs.

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: Calculate metadata requirements more accurately
  ext4: Fix accounting of reserved metadata blocks

We wrap the smm calls and other bits with the BKL push down as a
precaution but they can probably go
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Nobody seems to want to own I2O patches so sending this one directly.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The BKL is in this function because of the BKL pushdown (see commit
f8f2c79d)

It is not needed here because the mutex_lock sonypi_device.lock provides
the necessary locking.

sonypi_misc_ioctl can be converted to unlocked ioctls since it relies on
its own locking (the mutex sonypi_device.lock) and not the bkl

Document that llseek is not needed by explictly setting it to no_llseek

LKML-Reference: <alpine.LFD.2.00.0910192019420.3563@localhost.localdomain>
Signed-off-by: NJohn Kacur <jkacur@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
  nilfs2: update mailing list address
  nilfs2: Storage class should be before const qualifier
  nilfs2: trivial coding style fix

Initialize the glue by calling snd_soc_new_ac97_codec() as is done
in other ASoC AC97 codecs.  Fixes an oops caused by dereferencing
uninitialized members in snd_soc_new_pcms().

Run-tested on Au1250.
Signed-off-by: NManuel Lauss <manuel.lauss@gmail.com>
Acked-by: NLiam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

We want to be sure that compiler fetches the limit variable only
once, so add helpers for fetching current and maximal resource
limits which do that.

Add them to sched.h (instead of resource.h) due to circular dependency
 sched.h->resource.h->task_struct
Alternative would be to create a separate res_access.h or similar.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: James Morris <jmorris@namei.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>

It is an internal function. Move it inside __KERNEL__ ifdef, along
with task_struct declaration.

Then we get:
--- /usr/include/linux/resource.h       2009-09-14 15:09:29.000000000 +0200
+++ usr/include/linux/resource.h       2010-01-04 11:30:54.000000000 +0100
@@ -3,8 +3,6 @@

 #include <linux/time.h>

-struct task_struct;
-
 /*
  * Resource control/accounting header file for linux
  */
@@ -70,6 +68,5 @@
  */
 #include <asm/resource.h>

-int getrusage(struct task_struct *p, int who, struct rusage *ru);

 #endif

***********

include/linux/Kbuild is untouched, since unifdef is run even on
headers-y nowadays.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>