Commit Graph

145284 Commits

Author SHA1 Message Date
K.Prasad 0722db015c hw-breakpoints: ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces
This patch adds an ftrace plugin to detect and profile memory access over kernel
variables. It uses HW Breakpoint interfaces to 'watch memory addresses.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:47:00 +02:00
K.Prasad 432039933a hw-breakpoints: sample HW breakpoint over kernel data address
This patch introduces a sample kernel module to demonstrate the use of Hardware
Breakpoint feature. It places a breakpoint over the kernel variable 'pid_max'
to monitor all write operations and emits a function-backtrace when done.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:47:00 +02:00
K.Prasad 17f557e5b5 hw-breakpoints: cleanup HW Breakpoint registers before kexec
This patch disables Hardware breakpoints before doing a 'kexec' on the machine
so that the cpu doesn't keep debug registers values which would be out of
sync for the new image.

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:47:00 +02:00
K.Prasad 72f674d203 hw-breakpoints: modify Ptrace routines to access breakpoint registers
This patch modifies the ptrace code to use the new wrapper routines around the
debug/breakpoint registers.

[ Impact: adapt x86 ptrace to the new breakpoint Api ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Maneesh Soni <maneesh@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:59 +02:00
K.Prasad da0cdc14f5 hw-breakpoints: modify signal handling code to refrain from re-enabling HW Breakpoints
This patch disables re-enabling of Hardware Breakpoint registers through
the signal handling code. This is now done during from hw_breakpoint_handler().

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:59 +02:00
K.Prasad 66cb591729 hw-breakpoints: use the new wrapper routines to access debug registers in process/thread code
This patch enables the use of abstract debug registers in
process-handling routines, according to the new hardware breakpoint
Api.

[ Impact: adapt thread breakpoints handling code to the new breakpoint Api ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:59 +02:00
K.Prasad 1e3500666f hw-breakpoints: use wrapper routines around debug registers in processor related functions
This patch enables the use of wrapper routines to access the debug/breakpoint
registers on cpu management.

The hardcoded debug registers save and restore operations for threads
breakpoints are replaced by wrappers.

And now that we handle the kernel breakpoints too, we also need to handle them
on cpu hotplug operations.

[ Impact: adapt new hardware breakpoint api to cpu hotplug ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:59 +02:00
K.Prasad 08d68323d1 hw-breakpoints: modifying generic debug exception to use thread-specific debug registers
This patch modifies the breakpoint exception handler code to use the new
abstract debug register names.

[ fweisbec@gmail.com: fix conflict against kmemcheck ]

[ Impact: refactor and cleanup x86 debug exception handler ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:58 +02:00
K.Prasad 0067f12972 hw-breakpoints: x86 architecture implementation of Hardware Breakpoint interfaces
This patch introduces the arch-specific implementation of the generic
hardware breakpoints in kernel/hw_breakpoint.c inside x86 specific directories.
It contains functions which help to validate and serve requests using
Hardware Breakpoint registers on x86 processors.

[ fweisbec@gmail.com: fix conflict against kmemcheck ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:58 +02:00
K.Prasad 62a038d34d hw-breakpoints: introducing generic hardware breakpoint handler interfaces
This patch introduces the generic Hardware Breakpoint interfaces for both user
and kernel space requests.
This core Api handles the hardware breakpoints through new helpers. It
handles the user-space breakpoints and kernel breakpoints in front of
arch implementation.

One can choose kernel wide breakpoints using the following helpers
and passing them a generic struct hw_breakpoint:

- register_kernel_hw_breakpoint()
- unregister_kernel_hw_breakpoint()
- modify_kernel_hw_breakpoint()

On the other side, you can choose per task breakpoints.

- register_user_hw_breakpoint()
- unregister_user_hw_breakpoint()
- modify_user_hw_breakpoint()

[ fweisbec@gmail.com: fix conflict against perfcounter ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:58 +02:00
K.Prasad b332828c39 hw-breakpoints: prepare the code for Hardware Breakpoint interfaces
The generic hardware breakpoint interface provides an abstraction of
hardware breakpoints in front of specific arch implementations for both kernel
and user side breakpoints.
This includes execution breakpoints and read/write breakpoints, also known as
"watchpoints".

This patch introduces header files containing constants, structure definitions
and declaration of functions used by the hardware breakpoint core and x86
specific code.
It also introduces an array based storage for the debug-register values in
'struct thread_struct', while modifying all users of debugreg<n> member in the
structure.

[ Impact: add headers for new hardware breakpoint interface ]

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:46:57 +02:00
Frederic Weisbecker 43bd123623 tracing/stat: remove unappropriate safe walk on list
register_stat_tracer() uses list_for_each_entry_safe
to check whether a tracer is already present in the list.
But we don't delete anything from the list here, so
we don't need the safe version

[ Impact: cleanup list use is stat tracing ]

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:18:33 +02:00
Li Zefan dbd3fbdfee tracing/stat: do some cleanups
- remove duplicate code in stat_seq_init()
- update comments to reflect the change from stat list to stat rbtree

[ Impact: clean up ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:18:18 +02:00
Li Zefan e162280690 tracing/stat: remember to free root node
When closing a trace_stat file, we destroy the rbtree constructed during
file open, but there is memory leak that the root node is not freed.

[ Impact: fix memory leak when closing a trace_stat file ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:18:03 +02:00
Li Zefan b3dd7ba7d8 tracing/stat: change dummpy_cmp() to return -1
Currently the output of trace_stat/workqueues is totally reversed:

 # cat /debug/tracing/trace_stat/workqueues
    ...
    1       17       17      210       37   `-blk_unplug_work+0x0/0x57
    1     3779     3779      181       11   |-cfq_kick_queue+0x0/0x2f
    1     3796     3796                     kblockd/1:120
    ...

The correct output should be:

    1     3796     3796                     kblockd/1:120
    1     3779     3779      181       11   |-cfq_kick_queue+0x0/0x2f
    1       17       17      210       37   `-blk_unplug_work+0x0/0x57

It's caused by "tracing/stat: replace linked list by an rbtree for
sorting"
(53059c9b67a62a3dc8c80204d3da42b9267ea5a0).

dummpy_cmp() should return -1, so rb_node will always be inserted as
right-most node in the rbtree, thus we sort the output in ascending
order.

[ Impact: fix the output of trace_stat/workqueues ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:17:49 +02:00
Frederic Weisbecker 8f184f2730 tracing/stat: replace linked list by an rbtree for sorting
When the stat tracing framework prepares the entries from a tracer
to output them to the user, it starts by computing a linear sort
through a linked list to give the entries ordered by relevance
to the user.

This is quite ugly and causes a small latency when we begin to
read the file.

This patch changes that by turning the linked list into a red-black
tree. Athough the whole iteration using the start and next tracer
callbacks while opening the file remain the same, it is now much
more fast and scalable.

The rbtree guarantees O(log(n)) insertions whereas a linked
list with linear sorting brought us a O(n) despair. Now the
(visible) latency has disapeared.

[ Impact: kill the latency while starting to read a stat tracer file ]

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:17:35 +02:00
Frederic Weisbecker 0d64f8342d tracing/stat: replace trace_stat_session by stat_session
The "trace" prefix in struct trace_stat_session type is annoying while
reading the trace_stat.c file. It makes the lines longer, and
is not that much useful to explain the sense of this type.

Just keep "struct stat_session" for this type.

[ Impact: make the code a bit more readable ]

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:17:17 +02:00
Zhaolei f3c4ae26e9 trace_workqueue: remove blank line between each cpu
The blankline between each cpu's workqueue stat is not necessary, because
the cpu number is enough to part them by eye.
Old style also caused a blankline below headline, and made code complex
by using lock, disableirq and get cpu var.

Old style:
 # CPU  INSERTED  EXECUTED   NAME
 # |      |         |          |

   0   8644       8644       events/0
   0      0          0       cpuset
   ...
   0      1          1       kdmflush

   1  35365      35365       events/1
   ...

New style:
 # CPU  INSERTED  EXECUTED   NAME
 # |      |         |          |

   0   8644       8644       events/0
   0      0          0       cpuset
   ...
   0      1          1       kdmflush
   1  35365      35365       events/1
   ...

[ Impact: provide more readable code ]

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:14:26 +02:00
Zhaolei b8867164f0 trace_workqueue: remove cpu_workqueue_stats->first_entry
cpu_workqueue_stats->first_entry is useless because we can retrieve the
header of a cpu workqueue using:
if (&cpu_workqueue_stats->list == workqueue_cpu_stat(cpu)->list.next)

[ Impact: cleanup ]

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:13:46 +02:00
Zhaolei 1fdfca9c57 trace_workqueue: use list_for_each_entry() instead of list_for_each_entry_safe()
No need to use list_for_each_entry_safe() in iteration without deleting
any node, we can use list_for_each_entry() instead.

[ Impact: cleanup ]

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:13:05 +02:00
Zhaolei fb39125fd7 ftrace, workqueuetrace: make workqueue tracepoints use TRACE_EVENT macro
v3: zhaolei@cn.fujitsu.com: Change TRACE_EVENT definition to new format
    introduced by Steven Rostedt: consolidate trace and trace_event headers
v2: kosaki@jp.fujitsu.com: print the function names instead of addr, and zap
    the work addr
v1: zhaolei@cn.fujitsu.com: Make workqueue tracepoints use TRACE_EVENT macro

TRACE_EVENT is a more generic way to define tracepoints.
Doing so adds these new capabilities to the tracepoints:

  - zero-copy and per-cpu splice() tracing
  - binary tracing without printf overhead
  - structured logging records exposed under /debug/tracing/events
  - trace events embedded in function tracer output and other plugins
  - user-defined, per tracepoint filter expressions

Then, this patch converts DEFINE_TRACE to TRACE_EVENT in workqueue related
tracepoints.

[ Impact: expand workqueue tracer to events tracing ]

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 01:10:40 +02:00
Zhaolei f2aebaee65 ftrace: don't convert function's local variable name in macro
"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: Zhao Lei <zhaolei@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-28 01:22:06 +02:00
Heiko Carstens 5b6045a906 trace: disable preemption before taking raw spinlocks
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: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-28 01:21:03 +02:00
Steven Rostedt c2adae0970 tracing: convert irq events to use __print_symbolic
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: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 20:32:30 +02:00
Steven Rostedt 0f4fc29dd6 tracing: add __print_symbolic to trace events
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: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 20:31:50 +02:00
Steven Rostedt 62ba180e80 tracing: add flag output for kmem events
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: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 20:31:14 +02:00
Steven Rostedt 937cdb9db7 tracing: add previous task state info to sched switch event
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: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 20:29:19 +02:00
Steven Rostedt be74b73a57 tracing: add __print_flags for events
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: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 20:25:22 +02:00
Zhaolei 0e907c9939 ftrace: clean up of using ftrace_event_enable_disable()
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: Zhao 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: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 03:30:31 +02:00
Zhaolei b11c53e12f ftrace: Add task_comm support for trace_event
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: Zhao 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: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 03:03:21 +02:00
Pekka Enberg 29fcefba8a kmemtrace: fix kernel parameter documentation
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: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <alpine.DEB.2.00.0905241112190.10296@rocky>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 03:03:21 +02:00
Li Zefan b0aae68cc5 tracing/events: change the type of __str_loc_item to unsigned short
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: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A14EDB6.2050507@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-26 00:15:21 +02:00
Lai Jiangshan 4f5359685a tracing: add trace_event_read_lock()
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: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A114806.7090302@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-25 23:53:41 +02:00
Ming Lei 5537937696 ftrace: fix check for return value of register_module_notifier in event_trace_init
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: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-20 19:23:11 +02:00
Stefan Raspl fd51d251e4 blktrace: remove debugfs entries on bad path
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: Stefan Raspl <stefan.raspl@linux.vnet.ibm.com>
Acked-by: Li 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: Ingo Molnar <mingo@elte.hu>
2009-05-19 10:29:21 +02:00
Li Zefan 143c145e3a tracing/events: Documentation updates
- 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: Li 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: Ingo Molnar <mingo@elte.hu>
2009-05-19 10:29:21 +02:00
Ming Lei 24ed0c4bfc tracing: fix check for return value of register_module_notifier
return zero should be correct, so fix it.

[ Impact: eliminate incorrect syslog message ]

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: rostedt@goodmis.org
LKML-Reference: <1242545498-7285-1-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-18 10:24:13 +02:00
Ingo Molnar 1079cac0f4 Merge commit 'v2.6.30-rc6' into tracing/core
Merge reason: we were on an -rc4 base, sync up to -rc6

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-18 10:15:35 +02:00
Linus Torvalds 1406de8e11 Linux 2.6.30-rc6 2009-05-15 21:12:57 -07:00
Linus Torvalds 72357d5955 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6
* '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
2009-05-15 16:47:55 -07:00
Linus Torvalds 7c7327d966 Merge git://git.kernel.org/pub/scm/linux/kernel/git/holtmann/bluetooth-2.6
* 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!
2009-05-15 14:30:02 -07:00
Linus Torvalds 40f293ff83 Merge branch 'drm-intel-next' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel
* '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.
2009-05-15 13:22:11 -07:00
Linus Torvalds 8c21f34126 Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
* '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
2009-05-15 12:04:49 -07:00
Linus Torvalds 3346857f6f Merge git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6:
  iwlwifi: fix device id registration for 6000 series 2x2 devices
  ath5k: update channel in sw state after stopping RX and TX
  rtl8187: use DMA-aware buffers with usb_control_msg
  mac80211: avoid NULL ptr deref when finding max_rates in PID and minstrel
  airo: airo_get_encode{,ext} potential buffer overflow

Pulled directly by Linus because Davem is off playing shuffle-board at
some Alaskan cruise, and the NULL ptr deref issue hits people and should
get merged sooner rather than later.

David - make us proud on the shuffle-board tournament!
2009-05-15 12:02:06 -07:00
Martin K. Petersen 4bca328643 libata: Media rotation rate and form factor heuristics
This patch provides new heuristics for parsing both the form factor and
media rotation rate ATA IDENFITY words.

The reported ATA version must be 7 or greater and the device must return
values defined as valid in the standard.  Only then are the
characteristics reported to SCSI via the VPD B1 page.

This seems like a reasonable compromise to me considering that we have
been shipping several kernel releases that key off the rotation rate bit
without any version checking whatsoever.  With no complaints so far.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-05-15 14:14:56 -04:00
Martin K. Petersen 61d79a8eb3 libata: Report disk alignment and physical block size
For disks with 4KB sectors, report the correct block size and alignment
when filling out the READ CAPACITY(16) response.

This patch is based upon code from Matthew Wilcox' 4KB ATA tree.  I
fixed the bug I reported a while back caused by ATA and SCSI using
different approaches to describing the alignment.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-05-15 14:14:22 -04:00
Dave Liu d358724385 sata_fsl: Fix the command description of FSL SATA controller
The bit 11 of command description is reserved bit in Freescale
SATA controller and needs to be set to '1'.  This is needed to
make sure the last write from the controller to the buffer
descriptor is seen before an interrupt is raised.

Signed-off-by: Dave Liu <daveliu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-05-15 14:14:08 -04:00
Kumar Gala f48c019f15 sata_fsl: Fix compile warnings
We we build with dma_addr_t as a 64-bit quantity we get:

drivers/ata/sata_fsl.c: In function 'sata_fsl_fill_sg':
drivers/ata/sata_fsl.c:340: warning: format '%x' expects type 'unsigned int', but argument 4 has type 'dma_addr_t'

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-05-15 14:14:01 -04:00
David Milburn 19799bfc5d [libata] sata_sx4: fixup interrupt handling
Issuing ATA_CMD_SET_FEATURES (0xef) times out because
pdc20621_interrupt ignores command completion since
ATA_TFLAG_POLLING flag is set.

This has already been fixed for sata_promise:

commit 51b94d2a5a
Author: Tejun Heo <htejun@gmail.com>
Date:   Fri Jun 8 13:46:55 2007 -0700

    sata_promise: use TF interface for polling NODATA commands

Also, this patch includes Mikael's original patches:

http://marc.info/?l=linux-ide&m=121135828227724&w=2
http://marc.info/?l=linux-ide&m=121144512109826&w=2

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-05-15 14:08:10 -04:00
Jeff Garzik 67651ee571 [libata] sata_sx4: convert to new exception handling methods
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-05-15 14:05:22 -04:00