linux-stable.git/include/trace/ftrace.h, branch v3.10.78

tracing: Fix array size mismatch in format string

2014-03-31T16:58:12+00:00

commit 87291347c49dc40aa339f587b209618201c2e527 upstream.

In event format strings, the array size is reported in two locations.
One in array subscript and then via the "size:" attribute. The values
reported there have a mismatch.

For e.g., in sched:sched_switch the prev_comm and next_comm character
arrays have subscript values as [32] where as the actual field size is
16.

name: sched_switch
ID: 301
format:
        field:unsigned short common_type;       offset:0;       size:2; signed:0;
        field:unsigned char common_flags;       offset:2;       size:1; signed:0;
        field:unsigned char common_preempt_count;       offset:3;       size:1;signed:0;
        field:int common_pid;   offset:4;       size:4; signed:1;

        field:char prev_comm[32];       offset:8;       size:16;        signed:1;
        field:pid_t prev_pid;   offset:24;      size:4; signed:1;
        field:int prev_prio;    offset:28;      size:4; signed:1;
        field:long prev_state;  offset:32;      size:8; signed:1;
        field:char next_comm[32];       offset:40;      size:16;        signed:1;
        field:pid_t next_pid;   offset:56;      size:4; signed:1;
        field:int next_prio;    offset:60;      size:4; signed:1;

After bisection, the following commit was blamed:
92edca0 tracing: Use direct field, type and system names

This commit removes the duplication of strings for field->name and
field->type assuming that all the strings passed in
__trace_define_field() are immutable. This is not true for arrays, where
the type string is created in event_storage variable and field->type for
all array fields points to event_storage.

Use __stringify() to create a string constant for the type string.

Also, get rid of event_storage and event_storage_mutex that are not
needed anymore.

also, an added benefit is that this reduces the overhead of events a bit more:

   text    data     bss     dec     hex filename
8424787 2036472 1302528 11763787         b3804b vmlinux
8420814 2036408 1302528 11759750         b37086 vmlinux.patched

Link: http://lkml.kernel.org/r/1392349908-29685-1-git-send-email-vnagarnaik@google.com

Cc: Laurent Chavey 
Signed-off-by: Vaibhav Nagarnaik 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Allow events to have NULL strings

2013-12-04T18:57:17+00:00

commit 4e58e54754dc1fec21c3a9e824bc108b05fdf46e upstream.

If an TRACE_EVENT() uses __assign_str() or __get_str on a NULL pointer
then the following oops will happen:

BUG: unable to handle kernel NULL pointer dereference at   (null)
IP: [] strlen+0x10/0x1a
*pde = 00000000 ^M
Oops: 0000 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.13.0-rc1-test+ #2
Hardware name:                  /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006^M
task: f5cde9f0 ti: f5e5e000 task.ti: f5e5e000
EIP: 0060:[] EFLAGS: 00210046 CPU: 1
EIP is at strlen+0x10/0x1a
EAX: 00000000 EBX: c2472da8 ECX: ffffffff EDX: c2472da8
ESI: c1c5e5fc EDI: 00000000 EBP: f5e5fe84 ESP: f5e5fe80
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 8005003b CR2: 00000000 CR3: 01f32000 CR4: 000007d0
Stack:
 f5f18b90 f5e5feb8 c10687a8 0759004f 00000005 00000005 00000005 00200046
 00000002 00000000 c1082a93 f56c7e28 c2472da8 c1082a93 f5e5fee4 c106bc61^M
 00000000 c1082a93 00000000 00000000 00000001 00200046 00200082 00000000
Call Trace:
 [] ftrace_raw_event_lock+0x39/0xc0
 [] ? ktime_get+0x29/0x69
 [] ? ktime_get+0x29/0x69
 [] lock_release+0x57/0x1a5
 [] ? ktime_get+0x29/0x69
 [] read_seqcount_begin.constprop.7+0x4d/0x75
 [] ? ktime_get+0x29/0x69^M
 [] ktime_get+0x29/0x69
 [] __tick_nohz_idle_enter+0x1e/0x426
 [] ? lock_release_holdtime.part.19+0x48/0x4d
 [] ? time_hardirqs_off+0xe/0x28
 [] ? trace_hardirqs_off_caller+0x3f/0xaf
 [] tick_nohz_idle_enter+0x59/0x62
 [] cpu_startup_entry+0x64/0x192
 [] start_secondary+0x277/0x27c
Code: 90 89 c6 89 d0 88 c4 ac 38 e0 74 09 84 c0 75 f7 be 01 00 00 00 89 f0 48 5e 5d c3 55 89 e5 57 66 66 66 66 90 83 c9 ff 89 c7 31 c0  ae f7 d1 8d 41 ff 5f 5d c3 55 89 e5 57 66 66 66 66 90 31 ff
EIP: [] strlen+0x10/0x1a SS:ESP 0068:f5e5fe80
CR2: 0000000000000000
---[ end trace 01bc47bf519ec1b2 ]---

New tracepoints have been added that have allowed for NULL pointers
being assigned to strings. To fix this, change the TRACE_EVENT() code
to check for NULL and if it is, it will assign "(null)" to it instead
(similar to what glibc printf does).

Reported-by: Shuah Khan 
Reported-by: Jovi Zhangwei 
Link: http://lkml.kernel.org/r/CAGdX0WFeEuy+DtpsJzyzn0343qEEjLX97+o1VREFkUEhndC+5Q@mail.gmail.com
Link: http://lkml.kernel.org/r/528D6972.9010702@samsung.com
Fixes: 9cbf117662e2 ("tracing/events: provide string with undefined size support")
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Remove obsolete macro guard _TRACE_PROFILE_INIT

2013-04-13T03:02:33+00:00

The macro _TRACE_PROFILE_INIT was removed a long time ago,
but an "#undef" guard was left behind. Remove it.

Link: http://lkml.kernel.org/r/514684EE.6000805@huawei.com

Signed-off-by: zhangwei(Jovi) 
Signed-off-by: Steven Rostedt

tracing: Add a way to soft disable trace events

2013-03-15T04:36:03+00:00

In order to let triggers enable or disable events, we need a 'soft'
method for doing so. For example, if a function probe is added that
lets a user enable or disable events when a function is called, that
change must be done without taking locks or a mutex, and definitely
it can't sleep. But the full enabling of a tracepoint is expensive.

By adding a 'SOFT_DISABLE' flag, and converting the flags to be updated
without the protection of a mutex (using set/clear_bit()), this soft
disable flag can be used to allow critical sections to enable or disable
events from being traced (after the event has been placed into "SOFT_MODE").

Some caveats though: The comm recorder (to map pids with a comm) can not
be soft disabled (yet). If you disable an event with with a "soft"
disable and wait a while before reading the trace, the comm cache may be
replaced and you'll get a bunch of <...> for comms in the trace.

Reading the "enable" file for an event that is disabled will now give
you "0*" where the '*' denotes that the tracepoint is still active but
the event itself is "disabled".

[ fixed _BIT used in & operation : thanks to Dan Carpenter and smatch ]

Cc: Dan Carpenter 
Cc: Tom Zanussi 
Signed-off-by: Steven Rostedt

tracing: Fix some section mismatch warnings

2013-03-15T04:34:54+00:00

As we've added __init annotation to field-defining functions, we should
add __refdata annotation to event_call variables, which reference those
functions.

Link: http://lkml.kernel.org/r/51343C1F.2050502@huawei.com

Reported-by: Fengguang Wu 
Signed-off-by: Li Zefan 
Signed-off-by: Steven Rostedt

tracing: Annotate event field-defining functions with __init

2013-03-15T04:34:51+00:00

Those functions are called either during kernel boot or module init.

Before:

$ dmesg | grep 'Freeing unused kernel memory'
Freeing unused kernel memory: 1208k freed
Freeing unused kernel memory: 1360k freed
Freeing unused kernel memory: 1960k freed

After:

$ dmesg | grep 'Freeing unused kernel memory'
Freeing unused kernel memory: 1236k freed
Freeing unused kernel memory: 1388k freed
Freeing unused kernel memory: 1960k freed

Link: http://lkml.kernel.org/r/5125877D.5000201@huawei.com

Signed-off-by: Li Zefan 
Signed-off-by: Steven Rostedt

tracing: Add a helper function for event print functions

2013-03-15T04:34:51+00:00

Move duplicate code in event print functions to a helper function.

This shrinks the size of the kernel by ~13K.

   text    data     bss     dec     hex filename
6596137 1743966 10138672        18478775        119f6b7 vmlinux.o.old
6583002 1743849 10138672        18465523        119c2f3 vmlinux.o.new

Link: http://lkml.kernel.org/r/51258746.2060304@huawei.com

Signed-off-by: Li Zefan 
Signed-off-by: Steven Rostedt

tracing: Pass the ftrace_file to the buffer lock reserve code

2013-03-15T04:34:42+00:00

Pass the struct ftrace_event_file *ftrace_file to the
trace_event_buffer_lock_reserve() (new function that replaces the
trace_current_buffer_lock_reserver()).

The ftrace_file holds a pointer to the trace_array that is in use.
In the case of multiple buffers with different trace_arrays, this
allows different events to be recorded into different buffers.

Also fixed some of the stale comments in include/trace/ftrace.h

Signed-off-by: Steven Rostedt

tracing: Separate out trace events from global variables

2013-03-15T04:34:40+00:00

The trace events for ftrace are all defined via global variables.
The arrays of events and event systems are linked to a global list.
This prevents multiple users of the event system (what to enable and
what not to).

By adding descriptors to represent the event/file relation, as well
as to which trace_array descriptor they are associated with, allows
for more than one set of events to be defined. Once the trace events
files have a link between the trace event and the trace_array they
are associated with, we can create multiple trace_arrays that can
record separate events in separate buffers.

Signed-off-by: Steven Rostedt

tracing: Kill unused and puzzled sample code in ftrace.h

2012-11-13T20:51:21+00:00

When doing per-cpu helper optimizing work, find that this code is so puzzled.
1. It's mark as comment text, maybe a sample function for guidelines
   or a todo work.
2. But, this sample code is odd where struct perf_trace_buf is nonexistent.
   commit ce71b9 delete struct perf_trace_buf definition.

   Author: Frederic Weisbecker 
   Date:   Sun Nov 22 05:26:55 2009 +0100

   tracing: Use the perf recursion protection from trace event

Is it necessary to keep there?
just compile test.

Link: http://lkml.kernel.org/r/50949FC9.6050202@gmail.com

Signed-off-by: Shan Wei 
Signed-off-by: Steven Rostedt