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[PATCH v8 0/4] trace: Introduce objtrace trigger to trace the kernel object

Jeff Xie posted 4 patches 4 years, 5 months ago
There is a newer version of this series
Documentation/trace/events.rst                |  83 +++
include/linux/trace_events.h                  |   1 +
kernel/trace/Kconfig                          |  10 +
kernel/trace/Makefile                         |   1 +
kernel/trace/trace.c                          |   3 +
kernel/trace/trace.h                          |   8 +
kernel/trace/trace_entries.h                  |  18 +
kernel/trace/trace_events_trigger.c           |   1 +
kernel/trace/trace_object.c                   | 631 ++++++++++++++++++
kernel/trace/trace_output.c                   |  40 ++
.../ftrace/test.d/trigger/trigger-objtrace.tc |  39 ++
11 files changed, 835 insertions(+)
create mode 100644 kernel/trace/trace_object.c
create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc
[PATCH v8 0/4] trace: Introduce objtrace trigger to trace the kernel object
Posted by Jeff Xie 4 years, 5 months ago 
Introduce a method based on function tracer to trace any object and get
the value of the object dynamically. the object can be obtained from the
dynamic event (kprobe_event/uprobe_event) or the static event(tracepoint).

Usage:
When using the kprobe event, only need to set the objtrace(a new trigger),
we can get the value of the object. The object is from the setting of the 
kprobe event.

For example:
For the function bio_add_page():

int bio_add_page(struct bio *bio, struct page *page,
	unsigned int len, unsigned int offset)

Firstly, we can set the base of the object, thus the first string "arg1"
stands for the value of the first parameter of this function bio_add_gage(),

# echo 'p bio_add_page arg1=$arg1' > ./kprobe_events

Secondly, we can get the value dynamically based on above object. 

find the offset of the bi_size in struct bio:
$ gdb vmlinux
(gdb) p &(((struct bio *)0)->bi_iter.bi_size)
$1 = (unsigned int *) 0x28

# echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
	p_bio_add_page_0/trigger

# cd /sys/kernel/debug/tracing/
# echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
# echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger

# du -sh /test.txt
12.0K   /test.txt

# cat  /test.txt > /dev/null
# cat ./trace
# tracer: nop
#
# entries-in-buffer/entries-written: 128/128   #P:4
#
#                                _-----=> irqs-off/BH-disabled
#                               / _----=> need-resched
#                              | / _---=> hardirq/softirq
#                              || / _--=> preempt-depth
#                              ||| / _-=> migrate-disable
#                              |||| /     delay
#           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
#              | |         |   |||||     |         |
             cat-117     [002] ...1.     1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
             cat-117     [002] ...1.     1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
             cat-117     [002] ...2.     1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
             cat-117     [002] ...1.     1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
             cat-117     [002] ...1.     1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
             cat-117     [002] ...2.     1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
             cat-117     [002] ...1.     1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
             cat-117     [002] ...1.     1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
             cat-117     [002] ...1.     1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
             cat-117     [002] ...1.     1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
          <idle>-0       [002] d..3.     1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
          <idle>-0       [002] d..3.     1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
          <idle>-0       [002] d..3.     1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
          <idle>-0       [002] d..3.     1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
          <idle>-0       [002] d..3.     1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
          <idle>-0       [002] d..3.     1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
          <idle>-0       [002] d..3.     1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
          <idle>-0       [002] d..3.     1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
	  ...

Almost all changelogs were suggested by Masami(mhiramat@kernel.org)
and steve(rostedt@goodmis.org), thank you all so much.

v8:
- revert to use per-cpu recursion for the function trace_object_events_call
- recover the filter when getting the value of the object
- simplify the implementation for the function get_object_value
- fix the build error

v7:
- use fixed-size array for object pool instead of list structure
- use ftrace_test_recursion_trylock for function trace hook function
- fix trace_object_ref reference count in the init_trace_object
- invoke exit_trace_object no matter whether data->ops->free is null 
  in the unregister_object_trigger
- release private_data of event_trigger_data in the trace_object_trigger_free
- remove [RFC] tag

v6:
- change the objtrace trigger syntax.
- add patchset description
- add <tracefs>/README

v5:
- add testcasts
- add check the field->size
- add lockless to search object
- describe the object trace more clearly in Kconfig

v4:
- please ignore the v4 which is the same as v3

v3:
- change the objfilter to objtrace
- add a command to the objfilter syntax
- change to get the value of the object
- use trace_find_event_field to find the field instead of using argN
- get data from @rec in the event trigger callback funciton

v2:
- adding a "objfilter" trigger to update object


Jeff Xie (4):
  trace: Add trace any kernel object
  trace/objtrace: get the value of the object
  trace/objtrace: Add testcases for objtrace
  trace/objtrace: Add documentation for objtrace

 Documentation/trace/events.rst                |  83 +++
 include/linux/trace_events.h                  |   1 +
 kernel/trace/Kconfig                          |  10 +
 kernel/trace/Makefile                         |   1 +
 kernel/trace/trace.c                          |   3 +
 kernel/trace/trace.h                          |   8 +
 kernel/trace/trace_entries.h                  |  18 +
 kernel/trace/trace_events_trigger.c           |   1 +
 kernel/trace/trace_object.c                   | 631 ++++++++++++++++++
 kernel/trace/trace_output.c                   |  40 ++
 .../ftrace/test.d/trigger/trigger-objtrace.tc |  39 ++
 11 files changed, 835 insertions(+)
 create mode 100644 kernel/trace/trace_object.c
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc

-- 
2.25.1
Re: [PATCH v8 0/4] trace: Introduce objtrace trigger to trace the kernel object
Posted by Masami Hiramatsu 4 years, 4 months ago 
Hi Jeff,

Thank you for updating the series, I'm testing the series and found some
issues. See below;

On Sun, 30 Jan 2022 22:44:26 +0800
Jeff Xie <xiehuan09@gmail.com> wrote:

> Introduce a method based on function tracer to trace any object and get
> the value of the object dynamically. the object can be obtained from the
> dynamic event (kprobe_event/uprobe_event) or the static event(tracepoint).
> 
> Usage:
> When using the kprobe event, only need to set the objtrace(a new trigger),
> we can get the value of the object. The object is from the setting of the 
> kprobe event.
> 
> For example:
> For the function bio_add_page():
> 
> int bio_add_page(struct bio *bio, struct page *page,
> 	unsigned int len, unsigned int offset)
> 
> Firstly, we can set the base of the object, thus the first string "arg1"
> stands for the value of the first parameter of this function bio_add_gage(),
> 
> # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> 
> Secondly, we can get the value dynamically based on above object. 
> 
> find the offset of the bi_size in struct bio:
> $ gdb vmlinux
> (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> $1 = (unsigned int *) 0x28
> 
> # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> 	p_bio_add_page_0/trigger
> 
> # cd /sys/kernel/debug/tracing/
> # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger

So doing after this command, I dumped the trigger file.

# cat events/kprobes/p_bio_add_page_0/trigger 
objtrace:count=1 if comm == "cat"

This is not correct. All the parameters are dropped. Thus I can not
remove the trigger without knowing the original command.

# echo '!objtrace:count=1 if comm == "cat"' >> ./events/kprobes/p_bio_add_page_0/trigger
sh: write error: Invalid argument

And there are another minor issue is here;

 # cd /sys/kernel/debug/tracing/
 # echo 'p bio_add_page $arg1 $arg2' > ./kprobe_events
 # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
 # echo '!objtrace:add:arg2' >> events/kprobes/p_bio_add_page_0/trigger 

Here, if I passed the "!objtrace:add:<a-field-exists-on-event>" then the objtrace
trigger was removed. But as you can see, the parameter is different.
Anyway, this is a minor issue, since we don't support multiple objtrace trigger
on the same event.

Could you fix these issues (and update the test case to check this?)

Thank you,

> 
> # du -sh /test.txt
> 12.0K   /test.txt
> 
> # cat  /test.txt > /dev/null
> # cat ./trace
> # tracer: nop
> #
> # entries-in-buffer/entries-written: 128/128   #P:4
> #
> #                                _-----=> irqs-off/BH-disabled
> #                               / _----=> need-resched
> #                              | / _---=> hardirq/softirq
> #                              || / _--=> preempt-depth
> #                              ||| / _-=> migrate-disable
> #                              |||| /     delay
> #           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
> #              | |         |   |||||     |         |
>              cat-117     [002] ...1.     1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
>              cat-117     [002] ...1.     1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
>              cat-117     [002] ...2.     1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
>              cat-117     [002] ...1.     1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
>              cat-117     [002] ...1.     1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
>              cat-117     [002] ...2.     1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
>              cat-117     [002] ...1.     1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
>              cat-117     [002] ...1.     1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
>              cat-117     [002] ...1.     1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
>              cat-117     [002] ...1.     1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
>           <idle>-0       [002] d..3.     1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
>           <idle>-0       [002] d..3.     1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
>           <idle>-0       [002] d..3.     1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
>           <idle>-0       [002] d..3.     1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
>           <idle>-0       [002] d..3.     1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
>           <idle>-0       [002] d..3.     1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
>           <idle>-0       [002] d..3.     1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
>           <idle>-0       [002] d..3.     1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> 	  ...
> 
> Almost all changelogs were suggested by Masami(mhiramat@kernel.org)
> and steve(rostedt@goodmis.org), thank you all so much.
> 
> v8:
> - revert to use per-cpu recursion for the function trace_object_events_call
> - recover the filter when getting the value of the object
> - simplify the implementation for the function get_object_value
> - fix the build error
> 
> v7:
> - use fixed-size array for object pool instead of list structure
> - use ftrace_test_recursion_trylock for function trace hook function
> - fix trace_object_ref reference count in the init_trace_object
> - invoke exit_trace_object no matter whether data->ops->free is null 
>   in the unregister_object_trigger
> - release private_data of event_trigger_data in the trace_object_trigger_free
> - remove [RFC] tag
> 
> v6:
> - change the objtrace trigger syntax.
> - add patchset description
> - add <tracefs>/README
> 
> v5:
> - add testcasts
> - add check the field->size
> - add lockless to search object
> - describe the object trace more clearly in Kconfig
> 
> v4:
> - please ignore the v4 which is the same as v3
> 
> v3:
> - change the objfilter to objtrace
> - add a command to the objfilter syntax
> - change to get the value of the object
> - use trace_find_event_field to find the field instead of using argN
> - get data from @rec in the event trigger callback funciton
> 
> v2:
> - adding a "objfilter" trigger to update object
> 
> 
> Jeff Xie (4):
>   trace: Add trace any kernel object
>   trace/objtrace: get the value of the object
>   trace/objtrace: Add testcases for objtrace
>   trace/objtrace: Add documentation for objtrace
> 
>  Documentation/trace/events.rst                |  83 +++
>  include/linux/trace_events.h                  |   1 +
>  kernel/trace/Kconfig                          |  10 +
>  kernel/trace/Makefile                         |   1 +
>  kernel/trace/trace.c                          |   3 +
>  kernel/trace/trace.h                          |   8 +
>  kernel/trace/trace_entries.h                  |  18 +
>  kernel/trace/trace_events_trigger.c           |   1 +
>  kernel/trace/trace_object.c                   | 631 ++++++++++++++++++
>  kernel/trace/trace_output.c                   |  40 ++
>  .../ftrace/test.d/trigger/trigger-objtrace.tc |  39 ++
>  11 files changed, 835 insertions(+)
>  create mode 100644 kernel/trace/trace_object.c
>  create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc
> 
> -- 
> 2.25.1
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>
Re: [PATCH v8 0/4] trace: Introduce objtrace trigger to trace the kernel object
Posted by Jeff Xie 4 years, 4 months ago 
Hi Masami,

On Mon, Jan 31, 2022 at 7:02 PM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> Hi Jeff,
>
> Thank you for updating the series, I'm testing the series and found some
> issues. See below;
>
> On Sun, 30 Jan 2022 22:44:26 +0800
> Jeff Xie <xiehuan09@gmail.com> wrote:
>
> > Introduce a method based on function tracer to trace any object and get
> > the value of the object dynamically. the object can be obtained from the
> > dynamic event (kprobe_event/uprobe_event) or the static event(tracepoint).
> >
> > Usage:
> > When using the kprobe event, only need to set the objtrace(a new trigger),
> > we can get the value of the object. The object is from the setting of the
> > kprobe event.
> >
> > For example:
> > For the function bio_add_page():
> >
> > int bio_add_page(struct bio *bio, struct page *page,
> >       unsigned int len, unsigned int offset)
> >
> > Firstly, we can set the base of the object, thus the first string "arg1"
> > stands for the value of the first parameter of this function bio_add_gage(),
> >
> > # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> >
> > Secondly, we can get the value dynamically based on above object.
> >
> > find the offset of the bi_size in struct bio:
> > $ gdb vmlinux
> > (gdb) p &(((struct bio *)0)->bi_iter.bi_size)
> > $1 = (unsigned int *) 0x28
> >
> > # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \
> >       p_bio_add_page_0/trigger
> >
> > # cd /sys/kernel/debug/tracing/
> > # echo 'p bio_add_page arg1=$arg1' > ./kprobe_events
> > # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
>
> So doing after this command, I dumped the trigger file.
>
> # cat events/kprobes/p_bio_add_page_0/trigger
> objtrace:count=1 if comm == "cat"
>
> This is not correct. All the parameters are dropped. Thus I can not
> remove the trigger without knowing the original command.
>
> # echo '!objtrace:count=1 if comm == "cat"' >> ./events/kprobes/p_bio_add_page_0/trigger
> sh: write error: Invalid argument
>
> And there are another minor issue is here;
>
>  # cd /sys/kernel/debug/tracing/
>  # echo 'p bio_add_page $arg1 $arg2' > ./kprobe_events
>  # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger
>  # echo '!objtrace:add:arg2' >> events/kprobes/p_bio_add_page_0/trigger
>
> Here, if I passed the "!objtrace:add:<a-field-exists-on-event>" then the objtrace
> trigger was removed. But as you can see, the parameter is different.
> Anyway, this is a minor issue, since we don't support multiple objtrace trigger
> on the same event.
>
> Could you fix these issues (and update the test case to check this?)

Thanks for finding these issues, I will fix them.

> Thank you,
>
> >
> > # du -sh /test.txt
> > 12.0K   /test.txt
> >
> > # cat  /test.txt > /dev/null
> > # cat ./trace
> > # tracer: nop
> > #
> > # entries-in-buffer/entries-written: 128/128   #P:4
> > #
> > #                                _-----=> irqs-off/BH-disabled
> > #                               / _----=> need-resched
> > #                              | / _---=> hardirq/softirq
> > #                              || / _--=> preempt-depth
> > #                              ||| / _-=> migrate-disable
> > #                              |||| /     delay
> > #           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
> > #              | |         |   |||||     |         |
> >              cat-117     [002] ...1.     1.602243: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> >              cat-117     [002] ...1.     1.602244: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x0
> >              cat-117     [002] ...2.     1.602244: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x1000
> >              cat-117     [002] ...1.     1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> >              cat-117     [002] ...1.     1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x1000
> >              cat-117     [002] ...2.     1.602245: bio_add_page <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x2000
> >              cat-117     [002] ...1.     1.602245: __bio_try_merge_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> >              cat-117     [002] ...1.     1.602245: __bio_add_page <-bio_add_page object:0xffff88811bee4000 value:0x2000
> >              cat-117     [002] ...1.     1.602245: submit_bio <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602245: submit_bio_noacct <-ext4_mpage_readpages object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602246: __submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602246: submit_bio_checks <-__submit_bio object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602246: __cond_resched <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602246: should_fail_bio <-submit_bio_checks object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602246: blk_mq_submit_bio <-submit_bio_noacct object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602246: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602246: blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602247: __rcu_read_lock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602247: __rcu_read_unlock <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> >              cat-117     [002] ...1.     1.602247: __blk_mq_alloc_requests <-blk_mq_submit_bio object:0xffff88811bee4000 value:0x3000
> >           <idle>-0       [002] d..3.     1.602298: bio_endio <-blk_update_request object:0xffff88811bee4000 value:0x0
> >           <idle>-0       [002] d..3.     1.602298: mpage_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> >           <idle>-0       [002] d..3.     1.602298: __read_end_io <-blk_update_request object:0xffff88811bee4000 value:0x0
> >           <idle>-0       [002] d..3.     1.602300: bio_put <-blk_update_request object:0xffff88811bee4000 value:0x0
> >           <idle>-0       [002] d..3.     1.602300: bio_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> >           <idle>-0       [002] d..3.     1.602300: mempool_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> >           <idle>-0       [002] d..3.     1.602300: mempool_free_slab <-blk_update_request object:0xffff88811bee4000 value:0x0
> >           <idle>-0       [002] d..3.     1.602300: kmem_cache_free <-blk_update_request object:0xffff88811bee4000 value:0x0
> >         ...
> >
> > Almost all changelogs were suggested by Masami(mhiramat@kernel.org)
> > and steve(rostedt@goodmis.org), thank you all so much.
> >
> > v8:
> > - revert to use per-cpu recursion for the function trace_object_events_call
> > - recover the filter when getting the value of the object
> > - simplify the implementation for the function get_object_value
> > - fix the build error
> >
> > v7:
> > - use fixed-size array for object pool instead of list structure
> > - use ftrace_test_recursion_trylock for function trace hook function
> > - fix trace_object_ref reference count in the init_trace_object
> > - invoke exit_trace_object no matter whether data->ops->free is null
> >   in the unregister_object_trigger
> > - release private_data of event_trigger_data in the trace_object_trigger_free
> > - remove [RFC] tag
> >
> > v6:
> > - change the objtrace trigger syntax.
> > - add patchset description
> > - add <tracefs>/README
> >
> > v5:
> > - add testcasts
> > - add check the field->size
> > - add lockless to search object
> > - describe the object trace more clearly in Kconfig
> >
> > v4:
> > - please ignore the v4 which is the same as v3
> >
> > v3:
> > - change the objfilter to objtrace
> > - add a command to the objfilter syntax
> > - change to get the value of the object
> > - use trace_find_event_field to find the field instead of using argN
> > - get data from @rec in the event trigger callback funciton
> >
> > v2:
> > - adding a "objfilter" trigger to update object
> >
> >
> > Jeff Xie (4):
> >   trace: Add trace any kernel object
> >   trace/objtrace: get the value of the object
> >   trace/objtrace: Add testcases for objtrace
> >   trace/objtrace: Add documentation for objtrace
> >
> >  Documentation/trace/events.rst                |  83 +++
> >  include/linux/trace_events.h                  |   1 +
> >  kernel/trace/Kconfig                          |  10 +
> >  kernel/trace/Makefile                         |   1 +
> >  kernel/trace/trace.c                          |   3 +
> >  kernel/trace/trace.h                          |   8 +
> >  kernel/trace/trace_entries.h                  |  18 +
> >  kernel/trace/trace_events_trigger.c           |   1 +
> >  kernel/trace/trace_object.c                   | 631 ++++++++++++++++++
> >  kernel/trace/trace_output.c                   |  40 ++
> >  .../ftrace/test.d/trigger/trigger-objtrace.tc |  39 ++
> >  11 files changed, 835 insertions(+)
> >  create mode 100644 kernel/trace/trace_object.c
> >  create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc
> >
> > --
> > 2.25.1
> >
>
>
> --
> Masami Hiramatsu <mhiramat@kernel.org>
---
JeffXie

Patchew 2.1-devel-ea86937

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