[GIT PULL] tracing: Updates for 5.10

[GIT PULL] tracing: Updates for 5.10

[Steven Rostedt]

Linus,

Updates for tracing and bootconfig:

- Add support for "bool" type in synthetic events

- Add per instance tracing for bootconfig

- Support perf-style return probe ("SYMBOL%return") in kprobes and uprobes

- Allow for kprobes to be enabled earlier in boot up

- Added tracepoint helper function to allow testing if tracepoints are
  enabled in headers

- Synthetic events can now have dynamic strings (variable length)

- Various fixes and cleanups


Please pull the latest trace-v5.10 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v5.10

Tag SHA1: 26ab68b2a2fa3a0e3724d4b025ca3a15dd7ec1f3
Head SHA1: 6107742d15832011cd0396d821f3225b52551f1f


Axel Rasmussen (1):
      tracing: support "bool" type in synthetic trace events

Dan Carpenter (1):
      tracing: remove a pointless assignment

Davidlohr Bueso (1):
      fgraph: Convert ret_stack tasklist scanning to rcu

Gaurav Kohli (1):
      tracing: Fix race in trace_open and buffer resize call

Jarkko Sakkinen (1):
      kprobes: Use module_name() macro

Masami Hiramatsu (21):
      tools/bootconfig: Show bootconfig compact tree from bootconfig file
      tools/bootconfig: Add list option
      tools/bootconfig: Make all functions static
      tools/bootconfig: Add a script to generate ftrace shell-command from bootconfig
      tools/bootconfig: Add a script to generates bootconfig from ftrace
      tools/bootconfig: Add --init option for bconf2ftrace.sh
      tracing/boot: Add per-instance tracing_on option support
      Documentation: tracing: Add tracing_on option to boot-time tracer
      tracing/kprobes: Support perf-style return probe
      tracing/uprobes: Support perf-style return probe
      Documentation: tracing: Add %return suffix description
      Documentation: tracing: boot: Add an example of tracing function-calls
      selftests/ftrace: Add %return suffix tests
      kprobes: Init kprobes in early_initcall
      tracing: Define event fields early stage
      tracing: Enable adding dynamic events early stage
      tracing: Enable creating new instance early boot
      tracing/boot, kprobe, synth: Initialize boot-time tracing earlier
      Documentation: tracing: Add the startup timing of boot-time tracing
      tracing/boot: Initialize per-instance event list in early boot
      tracing/boot: Add ftrace.instance.*.alloc_snapshot option

Qiujun Huang (2):
      ftrace: Fix some typos in comment
      tracing: Fix some typos in comments

Randy Dunlap (1):
      tracing: Delete repeated words in comments

Steven Rostedt (VMware) (8):
      tracepoints: Add helper to test if tracepoint is enabled in a header
      mm/page_ref: Convert the open coded tracepoint enabled to the new helper
      x86: Use tracepoint_enabled() for msr tracepoints instead of open coding it
      tracing: Change synthetic event string format to limit printed length
      ftrace: Simplify the hash calculation
      ftrace: Format variable declarations of ftrace_allocate_records
      tracing: Fix synthetic print fmt check for use of __get_str()
      tracing: Check return value of __create_val_fields() before using its result

Sudip Mukherjee (1):
      tracing: Remove a pointless assignment

Tom Zanussi (13):
      tracing: Change STR_VAR_MAX_LEN
      tracing: Fix parse_synth_field() error handling
      tracing: Save normal string variables
      tracing: Add support for dynamic strings to synthetic events
      tracing: Add README information for synthetic_events file
      selftests/ftrace: Add test case for synthetic event dynamic strings
      tracing: Don't show dynamic string internals in synthetic event description
      tracing: Move is_good_name() from trace_probe.h to trace.h
      tracing: Check that the synthetic event and field names are legal
      tracing: Add synthetic event error logging
      selftests/ftrace: Change synthetic event name for inter-event-combined test
      tracing: Handle synthetic event array field type checking correctly
      selftests/ftrace: Add test case for synthetic event syntax errors

Wei Yang (6):
      tracing: toplevel d_entry already initialized
      tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer
      ftrace: Use fls() to get the bits for dup_hash()
      ftrace: Simplify the dyn_ftrace->flags macro
      ftrace: Simplify the calculation of page number for ftrace_page->records
      ftrace: ftrace_global_list is renamed to ftrace_ops_list

Xianting Tian (1):
      tracing: Use __this_cpu_read() in trace_buffered_event_enable()

----
 Documentation/trace/boottime-trace.rst             |  38 ++
 Documentation/trace/events.rst                     |  15 +-
 Documentation/trace/histogram.rst                  |  18 +
 Documentation/trace/kprobetrace.rst                |   2 +
 Documentation/trace/tracepoints.rst                |  27 ++
 Documentation/trace/uprobetracer.rst               |   2 +
 MAINTAINERS                                        |   1 +
 arch/x86/include/asm/msr.h                         |  20 +-
 include/linux/ftrace.h                             |  11 +-
 include/linux/page_ref.h                           |  42 +--
 include/linux/tracepoint-defs.h                    |  34 ++
 kernel/kprobes.c                                   |   2 +-
 kernel/trace/fgraph.c                              |   8 +-
 kernel/trace/ftrace.c                              |  24 +-
 kernel/trace/ring_buffer.c                         |  10 +
 kernel/trace/synth_event_gen_test.c                |  18 +-
 kernel/trace/trace.c                               | 111 ++++--
 kernel/trace/trace.h                               |  31 +-
 kernel/trace/trace_boot.c                          |  23 +-
 kernel/trace/trace_dynevent.c                      |  10 +-
 kernel/trace/trace_events.c                        | 140 ++++---
 kernel/trace/trace_events_hist.c                   |  45 ++-
 kernel/trace/trace_events_synth.c                  | 413 ++++++++++++++++++---
 kernel/trace/trace_functions.c                     |  22 +-
 kernel/trace/trace_functions_graph.c               |   8 +-
 kernel/trace/trace_hwlat.c                         |   8 +-
 kernel/trace/trace_kprobe.c                        |  41 +-
 kernel/trace/trace_printk.c                        |   8 +-
 kernel/trace/trace_probe.h                         |  14 +-
 kernel/trace/trace_stack.c                         |  12 +-
 kernel/trace/trace_stat.c                          |   8 +-
 kernel/trace/trace_synth.h                         |   6 +-
 kernel/trace/trace_uprobe.c                        |  24 +-
 kernel/trace/tracing_map.c                         |   2 +-
 tools/bootconfig/main.c                            | 147 +++++---
 tools/bootconfig/scripts/bconf2ftrace.sh           | 199 ++++++++++
 tools/bootconfig/scripts/ftrace.sh                 | 109 ++++++
 tools/bootconfig/scripts/ftrace2bconf.sh           | 244 ++++++++++++
 tools/bootconfig/scripts/xbc.sh                    |  56 +++
 .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc   |   6 +
 .../test.d/kprobe/kretprobe_return_suffix.tc       |  21 ++
 .../ftrace/test.d/kprobe/uprobe_syntax_errors.tc   |   6 +
 .../trigger-inter-event-combined-hist.tc           |   8 +-
 .../trigger-synthetic-event-dynstring.tc           |  31 ++
 .../trigger-synthetic_event_syntax_errors.tc       |  19 +
 45 files changed, 1709 insertions(+), 335 deletions(-)
 create mode 100755 tools/bootconfig/scripts/bconf2ftrace.sh
 create mode 100644 tools/bootconfig/scripts/ftrace.sh
 create mode 100755 tools/bootconfig/scripts/ftrace2bconf.sh
 create mode 100644 tools/bootconfig/scripts/xbc.sh
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_return_suffix.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-dynstring.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic_event_syntax_errors.tc
---------------------------

Re: [GIT PULL] tracing: Updates for 5.10

[pr-tracker-bot]

The pull request you sent on Thu, 15 Oct 2020 13:53:45 -0400:

> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-v5.10

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/fefa636d815975b34afc45f50852a2810fb23ba9

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html

Re: [GIT PULL] tracing: Updates for 5.10

[Linus Torvalds]

On Thu, Oct 15, 2020 at 10:53 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Updates for tracing and bootconfig:

Hmm. I haven't verified that this came from you, but it seems likely..
Once again my clang build shows something that I don't see in my
allmodconfig gcc build:

   WARNING: modpost: vmlinux.o(.text+0x1e5b06): Section mismatch in
reference from the function __trace_early_add_events() to the function
.init.text:__trace_early_add_new_event()
   The function __trace_early_add_events() references
   the function __init __trace_early_add_new_event().
   This is often because __trace_early_add_events lacks a __init
   annotation or the annotation of __trace_early_add_new_event is wrong.

Hmm?

               Linus

Re: [GIT PULL] tracing: Updates for 5.10

[Steven Rostedt]

On Thu, 15 Oct 2020 18:54:34 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Thu, Oct 15, 2020 at 10:53 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Updates for tracing and bootconfig:  
> 
> Hmm. I haven't verified that this came from you, but it seems likely..
> Once again my clang build shows something that I don't see in my
> allmodconfig gcc build:
> 
>    WARNING: modpost: vmlinux.o(.text+0x1e5b06): Section mismatch in
> reference from the function __trace_early_add_events() to the function
> .init.text:__trace_early_add_new_event()
>    The function __trace_early_add_events() references
>    the function __init __trace_early_add_new_event().
>    This is often because __trace_early_add_events lacks a __init
>    annotation or the annotation of __trace_early_add_new_event is wrong.
> 
> Hmm?
> 
>                Linus

I see the issue, and I wonder if it has to do with optimization, for gcc
not to warn.

The issue is that we have:

trace_array_create() that can be called at any time. And it has:

	if (trace_instance_dir) {
		ret = trace_array_create_dir(tr);
		if (ret)
			goto out_free_tr;
	} else
		__trace_early_add_events(tr);


Where trace_instance_dir gets set at boot up, and thus the else statement
will never get called after that.

The __trace_early_add_events() then calls __trace_early_add_new_events()
which is __init.

I don't know how gcc didn't trigger this and clang does.

I'll have to think about how to untangle this. Is there some kind of
annotation that makes it show that a path can only be called at boot up and
not later?

-- Steve

Re: [GIT PULL] tracing: Updates for 5.10

[Masami Hiramatsu]

On Thu, 15 Oct 2020 18:54:34 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Thu, Oct 15, 2020 at 10:53 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Updates for tracing and bootconfig:
> 
> Hmm. I haven't verified that this came from you, but it seems likely..
> Once again my clang build shows something that I don't see in my
> allmodconfig gcc build:
> 
>    WARNING: modpost: vmlinux.o(.text+0x1e5b06): Section mismatch in
> reference from the function __trace_early_add_events() to the function
> .init.text:__trace_early_add_new_event()
>    The function __trace_early_add_events() references
>    the function __init __trace_early_add_new_event().
>    This is often because __trace_early_add_events lacks a __init
>    annotation or the annotation of __trace_early_add_new_event is wrong.
> 
> Hmm?

Oops, that's my fault.
The commit 720dee53ad8d ("tracing/boot: Initialize per-instance event list
 in early boot") removes __init from __trace_early_add_events() but I
forgot to do same on __trace_early_add_new_event().
Would this work?

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 851ab37058dd..e705f06c68c6 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2498,7 +2498,7 @@ __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
  * for enabling events at boot. We want to enable events before
  * the filesystem is initialized.
  */
-static __init int
+static int
 __trace_early_add_new_event(struct trace_event_call *call,
                            struct trace_array *tr)
 {


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [GIT PULL] tracing: Updates for 5.10

[Masami Hiramatsu]

On Thu, 15 Oct 2020 22:21:39 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Thu, 15 Oct 2020 18:54:34 -0700
> Linus Torvalds <torvalds@linux-foundation.org> wrote:
> 
> > On Thu, Oct 15, 2020 at 10:53 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> > >
> > > Updates for tracing and bootconfig:  
> > 
> > Hmm. I haven't verified that this came from you, but it seems likely..
> > Once again my clang build shows something that I don't see in my
> > allmodconfig gcc build:
> > 
> >    WARNING: modpost: vmlinux.o(.text+0x1e5b06): Section mismatch in
> > reference from the function __trace_early_add_events() to the function
> > .init.text:__trace_early_add_new_event()
> >    The function __trace_early_add_events() references
> >    the function __init __trace_early_add_new_event().
> >    This is often because __trace_early_add_events lacks a __init
> >    annotation or the annotation of __trace_early_add_new_event is wrong.
> > 
> > Hmm?
> > 
> >                Linus
> 
> I see the issue, and I wonder if it has to do with optimization, for gcc
> not to warn.

I also couldn't reproduce it even with CONFIG_DEBUG_SECTION_MISMATCH=y.
It seems that the __trace_early_add_new_event() is inlined in 
__trace_early_add_events(). 

$ eu-readelf -w kernel/trace/trace_events.o
...
 [ 1af20]    subprogram           abbrev: 53
             name                 (strp) "__trace_early_add_new_event"
             decl_file            (data1) trace_events.c (1)
             decl_line            (data2) 2502
             decl_column          (data1) 1
             prototyped           (flag_present) yes
             type                 (ref4) [    cc]
             inline               (data1) inlined (1)
$ gcc -v
...
gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04) 

> 
> The issue is that we have:
> 
> trace_array_create() that can be called at any time. And it has:
> 
> 	if (trace_instance_dir) {
> 		ret = trace_array_create_dir(tr);
> 		if (ret)
> 			goto out_free_tr;
> 	} else
> 		__trace_early_add_events(tr);
> 
> 
> Where trace_instance_dir gets set at boot up, and thus the else statement
> will never get called after that.
> 
> The __trace_early_add_events() then calls __trace_early_add_new_events()
> which is __init.
> 
> I don't know how gcc didn't trigger this and clang does.

> 
> I'll have to think about how to untangle this. Is there some kind of
> annotation that makes it show that a path can only be called at boot up and
> not later?

What happen if we use Peter's static_call() and update it after boot up? 
Or, we might need to break apart the trace_array_create() and restruct
it as __init trace_array_early_create() and trace_array_create().

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [GIT PULL] tracing: Updates for 5.10

[Steven Rostedt]

On Fri, 16 Oct 2020 11:53:23 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> > 
> > I'll have to think about how to untangle this. Is there some kind of
> > annotation that makes it show that a path can only be called at boot up and
> > not later?  
> 
> What happen if we use Peter's static_call() and update it after boot up? 

I think that's a bit over engineering ;-)

> Or, we might need to break apart the trace_array_create() and restruct
> it as __init trace_array_early_create() and trace_array_create().

That will likely make the code a bit more complex and possibly add as much
code as we save from the __init sections.

I think the best solution is what you proposed, and removing the __init,
and possibly making that function inline as well.

Care to send an official patch?

Thanks!

-- Steve

Re: [GIT PULL] tracing: Updates for 5.10

[Masami Hiramatsu]

On Thu, 15 Oct 2020 23:54:44 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Fri, 16 Oct 2020 11:53:23 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > > 
> > > I'll have to think about how to untangle this. Is there some kind of
> > > annotation that makes it show that a path can only be called at boot up and
> > > not later?  
> > 
> > What happen if we use Peter's static_call() and update it after boot up? 
> 
> I think that's a bit over engineering ;-)
> 
> > Or, we might need to break apart the trace_array_create() and restruct
> > it as __init trace_array_early_create() and trace_array_create().
> 
> That will likely make the code a bit more complex and possibly add as much
> code as we save from the __init sections.
> 
> I think the best solution is what you proposed, and removing the __init,
> and possibly making that function inline as well.
> 
> Care to send an official patch?

Sure, I'll send it.

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>

[PATCH] tracing: Remove __init from __trace_early_add_new_event()

[Masami Hiramatsu]

The commit 720dee53ad8d ("tracing/boot: Initialize per-instance event
list in early boot") removes __init from __trace_early_add_events()
but __trace_early_add_new_event() still has __init and will cause a
section mismatch.

Remove __init from __trace_early_add_new_event() as same as
__trace_early_add_events().

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace_events.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 851ab37058dd..e705f06c68c6 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2498,7 +2498,7 @@ __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
  * for enabling events at boot. We want to enable events before
  * the filesystem is initialized.
  */
-static __init int
+static int
 __trace_early_add_new_event(struct trace_event_call *call,
 			    struct trace_array *tr)
 {