The robust list pointers of user space held futexes are kept intact
over an exec() call. When the exec'ed task exits exit_robust_list() is
called with the stale pointer. The risk of corruption is minimal, but
still it is incorrect to keep the pointers valid. Actually glibc
should uninstall the robust list before calling exec() but we have to
deal with it anyway.

Nullify the pointers after [compat_]exit_robust_list() has been
called.
Reported-by: Anirban Sinha <ani@anirban.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Cc: stable@kernel.org

Commit f2e21c96 had unfortunate side
effects with cpufreq governors on some systems.

If the system did not switch into NOHZ mode ts->inidle is not set when
tick_nohz_stop_sched_tick() is called from the idle routine. Therefor
all subsequent calls from irq_exit() to tick_nohz_stop_sched_tick()
fail to call tick_nohz_start_idle(). This results in bogus idle
accounting information which is passed to cpufreq governors.

Set the inidle flag unconditionally of the NOHZ active state to keep
the idle time accounting correct in any case.

[ tglx: Added comment and tweaked the changelog ]
Reported-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Eero Nurkkala <ext-eero.nurkkala@nokia.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Greg KH <greg@kroah.com>
Cc: Steven Noonan <steven@uplinklabs.net>
Cc: stable@kernel.org
LKML-Reference: <1254907901.30157.93.camel@eenurkka-desktop>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

If futex_wait_requeue_pi() wakes prior to requeue, we drop the
reference to the source futex_key twice, once in
handle_early_requeue_pi_wakeup() and once on our way out.

Remove the drop from the handle_early_requeue_pi_wakeup() and keep
the get/drops together in futex_wait_requeue_pi().
Reported-by: Helge Bahmann <hcb@chaoticmind.net>
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Cc: Helge Bahmann <hcb@chaoticmind.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: stable-2.6.31 <stable@kernel.org>
LKML-Reference: <4ACCE21E.5030805@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Remy Bohmer pointed out that we create the hrtimer softirq thread even
when CONFIG_HIGH_RES_TIMERS is off. That results in a softirq-NULL
name for the thread.

Skip the thread creation/wakeup/teardown when CONFIG_HIGH_RES_TIMERS=n
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

commit 21ece08c (net: fix the xtables smp_processor_id assumptions for
-rt) fixed only half of the problem. The filter functions might run in
thread context and can be preempted and migrated on -RT.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Memory allocations in irq/preempt disabled regions is the main cause
of grief with these features. Needs some real work to get that solved.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

latency_lock is taken in the guts of the scheduler code and needs to
be a real spinlock on RT. convert it to atomic_spinlock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Resuscitated and enhanced the kernel latency histograms provided
originally by Yi Yang and adapted and converted by Steven Rostedt.

Latency histograms in the current version
- can be enabled online and independently
- have virtually no performance penalty when configured but not enabled
- have very little performance penalty when enabled
- use already available wakeup and switch tracepoints
- give corresponding results with the related tracer
- allow to record wakeup latency histograms of a single process
- record the process where the highest wakeup latency occurred 
- are documented in Documentation/trace/histograms.txt
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4AAEDDD5.4040505@osadl.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

The commit(f8382688) have converted swap to percpu locked, the
non-RT version of swap_get_cpu_var should be the same as the old
implementation, but in reality, it not works as the old one:

...
+#define swap_get_cpu_var(var, cpu)                     \
+       ({                                              \
+               (void)cpu;                              \
+               &get_cpu_var(var);                      \
+        })
...
 void __lru_cache_add(struct page *page, enum lru_list lru)
 {
-       struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
+       struct pagevec *pvec;
+       int cpu;

+       pvec = swap_get_cpu_var(lru_add_pvecs, cpu)[lru];
        page_cache_get(page);
        if (!pagevec_add(pvec, page))
                ____pagevec_lru_add(pvec, lru);
-       put_cpu_var(lru_add_pvecs);
+       swap_put_cpu_var(lru_add_pvecs, cpu);
 }

Here is the point, the old version:

      pvec = &get_cpu_var(lru_add_pvecs)[lru];
     	   = & (get_cpu_var(lru_add_pvecs)[lru]);

new version from commit f8382688:

      pvec = ({ (void)cpu; &get_cpu_var(lru_add_pvecs); })[lru];
           = (&get_cpu_var(lru_add_pvecs)) [lru];

so, we can see, these two are really different. and it made the non-RT boot
fail:

...

ide-gd driver 1.18
hda: max request size: 512KiB
hda: 312581808 sectors (160041 MB) w/8192KiB Cache, CHS=19457/255/63
hda: cache flushes supported
 hda:Unhandled kernel unaligned access[#1]:
Cpu 0
$ 0   : 0000000000000000 000000001400c4e1 98000000013699d0 0000000000000000
$ 4   : 0000000000000000 98000000be04f980 0000000000000010 000000007fd78b57
$ 8   : 0000000000000001 0000000000200200 0000000000100100 98000000be00f210
$12   : 000000001400c4e1 000000001000001e ffffffffffffffff 98000000bd0180a8
$16   : 0000000000000000 98000000be04f998 fffffffb81a72600 ffffffff802d3270
$20   : 0000000000000000 0000000000000000 ffffffffffffffef ffffffff80667a90
$24   : 0000000000000228 ffffffff803ded88
$28   : 98000000be04c000 98000000be04f950 00000000003fffff ffffffff80200404
Hi    : 0000000000000000
Lo    : 0000000000000320
epc   : ffffffff80217194 do_ade+0x298/0x3bc
    Not tainted
ra    : ffffffff80200404 ret_from_exception+0x0/0x10
Status: 1400c4e3    KX SX UX KERNEL EXL IE
Cause : 00000014
BadVA : fffffffb81a72607
PrId  : 00006303 (ICT Loongson-2)
Modules linked in:
Process swapper (pid: 1, threadinfo=98000000be04c000, task=98000000be04b7d8, tls=0000000000000000)
Stack : ffffffff80666f60 ffffffff8025165c 98000000013699d0 0000000000000001
        98000000bd00ae30 ffffffff80200404 0000000000000000 000000001400c4e1
        000000007fd78b57 98000000013699d0 ffffffff80638070 0000000000000002
        fffffffb81a72600 000000007fd78b57 0000000000000001 0000000000200200
        0000000000100100 98000000be00f210 98000000be00f220 000000000000001d
        ffffffffffffffff 98000000bd0180a8 98000000013699d0 0000000000000001
        98000000bd00ae30 ffffffff802d3270 0000000000000000 0000000000000000
        ffffffffffffffef ffffffff80667a90 0000000000000228 ffffffff803ded88
        98000000bd00ae30 98000000bd00ae30 98000000be04c000 98000000be04fab0
        00000000003fffff ffffffff80275350 000000001400c4e3 0000000000000000
        ...
Call Trace:
[<ffffffff80217194>] do_ade+0x298/0x3bc
[<ffffffff80200404>] ret_from_exception+0x0/0x10
[<ffffffff8027fafc>] __lru_cache_add+0x94/0xd8
[<ffffffff80275350>] add_to_page_cache_lru+0x84/0xa8
[<ffffffff80275520>] read_cache_page_async+0xa8/0x1dc
[<ffffffff80275664>] read_cache_page+0x10/0x74
[<ffffffff802fed34>] read_dev_sector+0x34/0xe0
[<ffffffff802ff96c>] adfspart_check_ICS+0x44/0x1b0
[<ffffffff802ff6e4>] rescan_partitions+0x178/0x3a8
[<ffffffff802d3840>] __blkdev_get+0x238/0x318
[<ffffffff802feeb0>] register_disk+0xd0/0x15c
[<ffffffff8037c1e8>] add_disk+0xcc/0x128
[<ffffffff803fcbc4>] ide_gd_probe+0x170/0x1d0
[<ffffffff803e6e08>] driver_probe_device+0xbc/0x180
[<ffffffff803e6f38>] __driver_attach+0x6c/0xa4
[<ffffffff803e6508>] bus_for_each_dev+0x58/0xa4
[<ffffffff803e5bbc>] bus_add_driver+0xc8/0x284
[<ffffffff803e72d8>] driver_register+0xc4/0x17c
[<ffffffff8020fa5c>] do_one_initcall+0x64/0x18c
[<ffffffff806701d8>] kernel_init+0xe0/0x14c
[<ffffffff80212e5c>] kernel_thread_helper+0x10/0x18

Code: 001188f8  00b1882d  de220000 <b2420007> b6420000  24120000  1640000c  00a0202d  8ca20120
Disabling lock debugging due to kernel taint
note: swapper[1] exited with preempt_count 1
Kernel panic - not syncing: Attempted to kill init!

This patch will keep the swap_get_cpu_var as the one before commit f8382688,
and put "(void)cpu;" to swap_put_cpu_var() to avoid warning about unused
variable.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
LKML-Reference: <1252034522-32653-1-git-send-email-wuzhangjin@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

We know already which code pathes trigger this so we can safely
disable it again and just keep the early return when mask == 0.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kvm->requests_lock is a sleeping lock in RT, but it's locked inside
the preempt disabled region of get_cpu(). Move the get_cpu() region
inside the spinlocked region to avoid the might sleep warning.

BUG: sleeping function called from invalid context at kernel/rtmutex.c:684
in_atomic(): 1, irqs_disabled(): 0, pid: 10670, name: qemu-kvm
Pid: 10670, comm: qemu-kvm Not tainted 2.6.31-rc9-rt9.1-32bit #47
Call Trace:
[<c022a88a>] __might_sleep+0xcb/0xd0
[<c0498bd9>] rt_spin_lock+0x29/0x5e
[<f9161b54>] make_all_cpus_request+0x36/0xb2 [kvm]
[<f9161bf6>] kvm_flush_remote_tlbs+0x12/0x1f [kvm]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Carsten Emde <carsten.emde@osadl.org>

rt_read_trylock() and rt_down_read_trylock() take the lock / semaphore
unconditionally when it is write locked. Check read_depth if current
owns the lock. If it's 0 we know it is write locked and return 0.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

If we pass a big size data over perf_counter_open() syscall,
the kernel will copy this data to a small buffer, it will
cause kernel crash.

This bug makes the kernel unsafe and non-root local user can
trigger it.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: <stable@kernel.org>
LKML-Reference: <4AAF37D4.5010706@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

set_normalized_timespec() nsec argument is of type long. The recent
timekeeping changes of ktime_get_ts() feed

	ts->tv_nsec + tomono.tv_nsec + nsecs

to set_normalized_timespec(). On 32 bit machines that sum can be
larger than (1 << 31) and therefor result in a negative value which
screws up the result completely.

Make the nsec argument of set_normalized_timespec() s64 to fix the
problem at hand. This also prevents similar problems for future users
of set_normalized_timespec().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Carsten Emde <carsten.emde@osadl.org>
LKML-Reference: <new-submission>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>

Merge branch 'tip/tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into rt/trace

Parag noticed that the number of event tests has increased tremendously:

grep "Testing event" dmesg.31rc9 |wc -l
100

grep "Testing event" dmesg.31git |wc -l
1172

This is due to the testing of every syscall event when ftrace self
test is enabled. This adds a bit more time to kernel boot up and can
affect development by slowing down the time it takes between reboots.

This option makes the testing of the syscall events into a separate
config, to still be able to test most of ftrace internals at boot up
but not have to wait for all the syscall events to be tested.

The syscall event testing only tests the enabling and disabling of
the trace point, since the syscalls are not executed. What really needs
to be done is to somehow have a userspace tool test the syscall tracepoints
as well.
Reported-by: Parag Warudkar <parag.lkml@gmail.com>
LKML-Reference: <f7848160909130815l3e768a30n3b28808bbe5c254b@mail.gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Conflicts:
	kernel/trace/ring_buffer.c
	kernel/trace/trace.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

- remove FTRACE_ENTRY_STRUCT_ONLY()
- remove TRACE_XXX() macros
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AADF6E6.3080606@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Make sure F_printk() has corrent format and args, and make sure
changes in F_STRUCT() won't break F_printk().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AADF6CC.1060809@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

I found some typos in F_printk(), so I wrote compile-time check
for it, and triggered some compile errors and warnings.

I've fixed them on x86_32, but I have no x86_64 in my hand, so there
may still be some compile warnings on 64bits.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AADF60B.5070407@cn.fujitsu.com>

[ tested on x86_64, and works fine ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The generated functions of TRACE_EVENT uses "flags" in one of the
sub macros which shadows a parameter in the outside macro.

Simple fix is to make the submacro use __flags instead.

Discovered by sparse.
Reported-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Some of the generated functions used in the TRACE_EVENT macros are
not declared static, but they are not global.

Discovered by sparse.
Reported-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The cmpxchg used by PowerPC does the following:

  ({									 \
     __typeof__(*(ptr)) _o_ = (o);					 \
     __typeof__(*(ptr)) _n_ = (n);					 \
     (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,		 \
				    (unsigned long)_n_, sizeof(*(ptr))); \
  })

This does a type check of *ptr to both o and n.

Unfortunately, the code in ring-buffer.c assigns longs to pointers
and pointers to longs and causes a warning on PowerPC:

ring_buffer.c: In function 'rb_head_page_set':
ring_buffer.c:704: warning: initialization makes pointer from integer without a cast
ring_buffer.c:704: warning: initialization makes pointer from integer without a cast
ring_buffer.c: In function 'rb_head_page_replace':
ring_buffer.c:797: warning: initialization makes integer from pointer without a cast

This patch adds the typecasts inside cmpxchg to annotate that a long is
being cast to a pointer and a pointer is being casted to a long and this
removes the PowerPC warnings.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Now that the pluging tracers use macros to create the structures and
automate the exporting of their formats to the format files, they also
automatically get a filter file.

This patch adds the code to implement the filter logic in the trace
recordings.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The macros in trace_entries.h have made the code in trace_event_types.h
obsolete. The file is no longer used, so this patch removes it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

This patch changes the way the format files in

  debugfs/tracing/events/ftrace/*/format

are created. It uses the new trace_entries.h file to automate the
creation of the format files to ensure that they are always in sync
with the actual structures. This is the same methodology used to
create the format files for the TRACE_EVENT macro.

This also updates the filter creation that was built on the creation
of the format files.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Some of the internal ftrace structures use structures within. The
output of a field saying it is just a structure is useless for a format
file. A binary reader of the ring buffer needs to know more about
how the fields are broken up.

This patch adds to the ftrace structure macros new fields to
describe the structures inside a structure.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The entries used by ftrace internal code (plugins) currently have their
formats manually exported to userspace. That is, the format files in
debugfs/tracing/events/ftrace/*/format are currently created by hand.
This is a maintenance nightmare, and can easily become out of sync
with what is actually shown.

This patch uses the methodology of the TRACE_EVENT macros to build
the structures so that their formats can be automated and this
will keep the structures in sync with what users can see.

This patch only changes the way the structures are created. Further
patches will build off of this to automate the format files.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

This patch increases the max string used by predicates to
handle KSYM_SYMBOL_LEN.

Also moves an include to look nicer.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Documentation for event filters and formats.

v2 changes: fix a few problems noticed by Randy Dunlap.
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1252642431.8016.9.camel@tropicana>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

If the correspoding module is unloaded before ftrace_profile_disable()
is called, event->profile_disable() won't be called, which can
cause oops:

  # insmod trace-events-sample.ko
  # perf record -f -a -e sample:foo_bar sleep 3 &
  # sleep 1
  # rmmod trace_events_sample
  # insmod trace-events-sample.ko
  OOPS!
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A9214E3.2070807@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Only 24 bytes needs to be reserved on the stack for the function graph
tracer on x86_64.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20090729085837.GB4998@jolsa.lab.eng.brq.redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

__start_mcount_loc[] is unused after init, yet occupies RAM forever
as part of .rodata.  152kiB is typical on a 64-bit architecture.  Instead,
__start_mcount_loc should be in the interval [__init_begin, __init_end)
so that the space is reclaimed after init.

__start_mcount_loc[] is generated during the load portion
of kernel build, and is used only by ftrace_init().  ftrace_init is declared
'__init' and is in .init.text, which is freed after init.
__start_mcount_loc is placed into .rodata by a call to MCOUNT_REC inside
the RO_DATA macro of include/asm-generic/vmlinux.lds.h.  The array *is*
read-only, but more importantly it is not used after init.  So the call to
MCOUNT_REC should be moved from RO_DATA to INIT_DATA.

This patch has been tested on x86_64 with CONFIG_DEBUG_PAGEALLOC=y
which verifies that the address range never is accessed after init.
Signed-off-by: John Reiser <jreiser@BitWagon.com>
LKML-Reference: <4A6DF0B6.7080402@bitwagon.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The state of the function pair tracing_stop()/tracing_start() is
correctly considered when tracer data are updated. However, the global
and externally accessible variable tracing_max_latency is always updated
- even when tracing is stopped.

The update should only occur, if tracing was not stopped.
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

When the nsecs_to_usecs() conversion in probe_wakeup_sched_switch() and
check_critical_timing() was moved to a later stage in order to avoid
unnecessary computing, it was overlooked to remove the original
variables, assignments and comments..
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Booting 2.6.31 and executing
   echo 1 >/sys/kernel/debug/tracing/events/enable
leads to
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c032a583>] ftrace_raw_event_block_bio_bounce+0x4b/0xb9

Apparently,
   bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
is called in block/blk-map.c:58 where bio->bi_bdev in set to NULL and
still is NULL when an attempt is made to evaluate bio->bi_bdev->bd_dev
in include/trace/events/block.h:189.

The tracepoint should ensure bio->bi_bdev is not dereferenced, if NULL.
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
LKML-Reference: <4AAAC9B1.9060505@osadl.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>