linux-toradex.git/kernel/trace/trace_stack.c, branch v2.6.31.12

trace_stack: Fix seqfile memory leak

2009-07-23T13:52:09+00:00

Every time we cat stack_trace, we leak memory allocated by seq_open().

Signed-off-by: Li Zefan 
LKML-Reference: <4A67D8E8.3020500@cn.fujitsu.com>
Signed-off-by: Steven Rostedt

tracing: Fix stack tracer sysctl handling

2009-06-26T18:48:39+00:00

This made my machine completely frozen:

  # echo 1 > /proc/sys/kernel/stack_tracer_enabled
  # echo 2 > /proc/sys/kernel/stack_tracer_enabled

The cause is register_ftrace_function() was called twice.

Also fix ftrace_enabled sysctl, though seems nothing bad happened
as I tested it.

Signed-off-by: Li Zefan 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
LKML-Reference: <4A448D17.9010305@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

tracing/trace_stack: fix the number of entries in the header

2009-06-03T14:24:44+00:00

The last entry in the stack_dump_trace is ULONG_MAX, which is not
a valid entry, but max_stack_trace.nr_entries has accounted for it.
So when printing the header, we should decrease it by one.
Before fix, print as following, for example:

	Depth    Size   Location    (53 entries)	<--- should be 52
	-----    ----   --------
  0)     3264     108   update_wall_time+0x4d5/0x9a0
  ...
 51)       80      80   syscall_call+0x7/0xb
 ^^^
   it's correct.

Signed-off-by: walimis 
LKML-Reference: <1244016090-7814-1-git-send-email-walimisdev@gmail.com>
Signed-off-by: Steven Rostedt

tracing/ftrace: factorize the tracing files creation

2009-04-07T12:43:07+00:00

Impact: cleanup

Most of the tracing files creation follow the same pattern:

ret = debugfs_create_file(...)
if (!ret)
	pr_warning("Couldn't create ... entry\n")

Unify it!

Reported-by: Ingo Molnar 
Signed-off-by: Frederic Weisbecker 
LKML-Reference: <1238109938-11840-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Steven Rostedt

tracing: left align location header in stack_trace

2009-03-13T04:00:58+00:00

Ingo Molnar suggested, instead of:

        Depth    Size      Location    (27 entries)
        -----    ----      --------
  0)     2880      48   lock_timer_base+0x2b/0x4f
  1)     2832      80   __mod_timer+0x33/0xe0
  2)     2752      16   __ide_set_handler+0x63/0x65

To have it be:

        Depth    Size   Location    (27 entries)
        -----    ----   --------
  0)     2880      48   lock_timer_base+0x2b/0x4f
  1)     2832      80   __mod_timer+0x33/0xe0
  2)     2752      16   __ide_set_handler+0x63/0x65

Requested-by: Ingo Molnar 
Signed-off-by: Steven Rostedt

tracing: explain why stack tracer is empty

2009-03-13T01:15:01+00:00

If the stack tracing is disabled (by default) the stack_trace file
will only contain the header:

 # cat /debug/tracing/stack_trace
        Depth    Size      Location    (0 entries)
        -----    ----      --------

This can be frustrating to a developer that does not realize that the
stack tracer is disabled. This patch adds the following text:

  # cat /debug/tracing/stack_trace
        Depth    Size      Location    (0 entries)
        -----    ----      --------
 #
 #  Stack tracer disabled
 #
 # To enable the stack tracer, either add 'stacktrace' to the
 # kernel command line
 # or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'
 #

Signed-off-by: Steven Rostedt

tracing: fix stack tracer header

2009-03-13T01:15:01+00:00

The stack tracer use to look like this:

 # cat /debug/tracing/stack_trace
         Depth  Size      Location    (57 entries)
         -----  ----      --------
  0)     5088      16   mempool_alloc_slab+0x16/0x18
  1)     5072     144   mempool_alloc+0x4d/0xfe
  2)     4928      16   scsi_sg_alloc+0x48/0x4a [scsi_mod]

Now it looks like this:

 # cat /debug/tracing/stack_trace

        Depth    Size      Location    (57 entries)
        -----    ----      --------
  0)     5088      16   mempool_alloc_slab+0x16/0x18
  1)     5072     144   mempool_alloc+0x4d/0xfe
  2)     4928      16   scsi_sg_alloc+0x48/0x4a [scsi_mod]

Signed-off-by: Steven Rostedt

trace: better use of stack_trace_enabled for boot up code

2008-12-18T11:56:56+00:00

Impact: clean up

Andrew Morton suggested to use the stack_tracer_enabled variable
to decide whether or not to start stack tracing on bootup.
This lets us remove the start_stack_trace variable.

Reported-by: Andrew Morton 
Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

trace: add a way to enable or disable the stack tracer

2008-12-18T11:56:24+00:00

Impact: enhancement to stack tracer

The stack tracer currently is either on when configured in or
off when it is not. It can not be disabled when it is configured on.
(besides disabling the function tracer that it uses)

This patch adds a way to enable or disable the stack tracer at
run time. It defaults off on bootup, but a kernel parameter 'stacktrace'
has been added to enable it on bootup.

A new sysctl has been added "kernel.stack_tracer_enabled" to let
the user enable or disable the stack tracer at run time.

Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

trace: fix output of stack trace

2008-12-03T16:15:02+00:00

Impact: fix to output of stack trace

If a function is not found in the stack of the stack tracer, the
number printed is quite strange. This fixes the algorithm to handle
missing functions better.

Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar