linux-toradex.git/include/trace/ftrace.h, branch v3.4.73

tracing: Allow events to have NULL strings

2013-12-04T18:50:34+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

perf: Fix counter of ftrace events

2011-10-04T09:07:54+00:00

Each event adds some points to its counters. By default it adds 1,
and a number of points may be transmited in event's parameters.

E.g. sched:sched_stat_runtime adds how long process has been running.

But this functionality was broken by v2.6.31-rc5-392-gf413cdb
and now the event's parameters doesn't affect on a number of points.

TP_perf_assign isn't defined, so __perf_count(c) isn't executed and
__count is always equal to 1.

Signed-off-by: Andrew Vagin 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1317052535-1765247-2-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar

tracing: Add __print_symbolic_u64 to avoid warnings on 32bit machine

2011-05-26T02:13:44+00:00

Filesystem, like Btrfs, has some "ULL" macros, and when these macros are passed
to tracepoints'__print_symbolic(), there will be 64->32 truncate WARNINGS during
compiling on 32bit box.

Signed-off-by: Liu Bo 
Link: http://lkml.kernel.org/r/4DACE6E0.7000507@cn.fujitsu.com
Signed-off-by: Steven Rostedt

tracing: Replace trace_event struct array with pointer array

2011-02-03T02:37:13+00:00

Currently the trace_event structures are placed in the _ftrace_events
section, and at link time, the linker makes one large array of all
the trace_event structures. On boot up, this array is read (much like
the initcall sections) and the events are processed.

The problem is that there is no guarantee that gcc will place complex
structures nicely together in an array format. Two structures in the
same file may be placed awkwardly, because gcc has no clue that they
are suppose to be in an array.

A hack was used previous to force the alignment to 4, to pack the
structures together. But this caused alignment issues with other
architectures (sparc).

Instead of packing the structures into an array, the structures' addresses
are now put into the _ftrace_event section. As pointers are always the
natural alignment, gcc should always pack them tightly together
(otherwise initcall, extable, etc would also fail).

By having the pointers to the structures in the section, we can still
iterate the trace_events without causing unnecessary alignment problems
with other architectures, or depending on the current behaviour of
gcc that will likely change in the future just to tick us kernel developers
off a little more.

The _ftrace_event section is also moved into the .init.data section
as it is now only needed at boot up.

Suggested-by: David Miller 
Cc: Mathieu Desnoyers 
Acked-by: David S. Miller 
Signed-off-by: Steven Rostedt

tracing/events: Show real number in array fields

2010-11-19T15:18:47+00:00

Currently we have in something like the sched_switch event:

  field:char prev_comm[TASK_COMM_LEN];	offset:12;	size:16;	signed:1;

When a userspace tool such as perf tries to parse this, the
TASK_COMM_LEN is meaningless. This is done because the TRACE_EVENT() macro
simply uses a #len to show the string of the length. When the length is
an enum, we get a string that means nothing for tools.

By adding a static buffer and a mutex to protect it, we can store the
string into that buffer with snprintf and show the actual number.
Now we get:

  field:char prev_comm[16];       offset:12;      size:16;        signed:1;

Something much more useful.

Signed-off-by: Steven Rostedt

tracing: Allow syscall trace events for non privileged users

2010-11-18T13:37:44+00:00

As for the raw syscalls events, individual syscall events won't
leak system wide information on task bound tracing. Allow non
privileged users to use them in such workflow.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Li Zefan 
Cc: Jason Baron

tracing: New macro to set up initial event flags value

2010-11-18T13:37:42+00:00

This introduces the new TRACE_EVENT_FLAGS() macro in order
to set up initial event flags value.

This macro must simply follow the definition of a trace event
and take the event name and the flag value as parameters:

TRACE_EVENT(my_event, .....
....
);

TRACE_EVENT_FLAGS(my_event, 1)

This will set up 1 as the initial my_event->flags value.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Li Zefan 
Cc: Jason Baron

tracing: Drop cpparg() macro

2010-08-01T23:31:28+00:00

Drop the cpparg() macro that wraps CPP parameters. We already have
the PARAM() macro for that, no need to have several versions.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Steven Rostedt 
Cc: Li Zefan

tracing: Reduce latency and remove percpu trace_seq

2010-07-21T02:05:34+00:00

__print_flags() and __print_symbolic() use percpu trace_seq:

1) Its memory is allocated at compile time, it wastes memory if we don't use tracing.
2) It is percpu data and it wastes more memory for multi-cpus system.
3) It disables preemption when it executes its core routine
   "trace_seq_printf(s, "%s: ", #call);" and introduces latency.

So we move this trace_seq to struct trace_iterator.

Signed-off-by: Lai Jiangshan 
LKML-Reference: <4C078350.7090106@cn.fujitsu.com>
Signed-off-by: Steven Rostedt

tracing: Use class->reg() for all registering of events

2010-06-29T01:13:14+00:00

Because kprobes and syscalls need special processing to register
events, the class->reg() method was created to handle the differences.

But instead of creating a default ->reg for perf and ftrace events,
the code was scattered with:

	if (class->reg)
		class->reg();
	else
		default_reg();

This is messy and can also lead to bugs.

This patch cleans up this code and creates a default reg() entry for
the events allowing for the code to directly call the class->reg()
without the condition.

Reported-by: Peter Zijlstra 
Acked-by: Peter Zijlstra 
Signed-off-by: Steven Rostedt