[for-next][PATCH 0/3] tracing: Final updates for 6.3

[for-next][PATCH 0/3] tracing: Final updates for 6.3

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace/for-next

Head SHA1: 2413ec4fd11248ef255f92fd12d943b49b6fbff4


Jianlin Lv (1):
      tracepoint: Allow livepatch module add trace event

Ross Zwisler (1):
      tracing: Always use canonical ftrace path

Wang ShaoBo (1):
      tracing: Remove unnecessary NULL assignment

----
 include/linux/kernel.h                    |  2 +-
 include/linux/tracepoint.h                |  4 ++--
 kernel/trace/Kconfig                      | 20 ++++++++++----------
 kernel/trace/kprobe_event_gen_test.c      |  2 +-
 kernel/trace/ring_buffer.c                |  2 +-
 kernel/trace/synth_event_gen_test.c       |  2 +-
 kernel/trace/trace.c                      |  2 +-
 kernel/trace/trace_events.c               |  2 --
 kernel/tracepoint.c                       |  4 ++--
 samples/user_events/example.c             |  4 ++--
 scripts/tracing/draw_functrace.py         |  6 +++---
 tools/lib/api/fs/tracing_path.c           |  4 ++--
 tools/tracing/latency/latency-collector.c |  2 +-
 13 files changed, 27 insertions(+), 29 deletions(-)

[for-next][PATCH 1/3] tracing: Always use canonical ftrace path

[Steven Rostedt]

From: Ross Zwisler <zwisler@chromium.org>

The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

  Before 4.1, all ftrace tracing control files were within the debugfs
  file system, which is typically located at /sys/kernel/debug/tracing.
  For backward compatibility, when mounting the debugfs file system,
  the tracefs file system will be automatically mounted at:

  /sys/kernel/debug/tracing

Many comments and Kconfig help messages in the tracing code still refer
to this older debugfs path, so let's update them to avoid confusion.

Link: https://lore.kernel.org/linux-trace-kernel/20230215223350.2658616-2-zwisler@google.com

Signed-off-by: Ross Zwisler <zwisler@google.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/kernel.h                    |  2 +-
 include/linux/tracepoint.h                |  4 ++--
 kernel/trace/Kconfig                      | 20 ++++++++++----------
 kernel/trace/kprobe_event_gen_test.c      |  2 +-
 kernel/trace/ring_buffer.c                |  2 +-
 kernel/trace/synth_event_gen_test.c       |  2 +-
 kernel/trace/trace.c                      |  2 +-
 samples/user_events/example.c             |  4 ++--
 scripts/tracing/draw_functrace.py         |  6 +++---
 tools/lib/api/fs/tracing_path.c           |  4 ++--
 tools/tracing/latency/latency-collector.c |  2 +-
 11 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index fe6efb24d151..40bce7495af8 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -297,7 +297,7 @@ bool mac_pton(const char *s, u8 *mac);
  *
  * Use tracing_on/tracing_off when you want to quickly turn on or off
  * tracing. It simply enables or disables the recording of the trace events.
- * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
+ * This also corresponds to the user space /sys/kernel/tracing/tracing_on
  * file, which gives a means for the kernel and userspace to interact.
  * Place a tracing_off() in the kernel where you want tracing to end.
  * From user space, examine the trace, and then echo 1 > tracing_on
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 4b33b95eb8be..fa1004fcf810 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -471,7 +471,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
  *	* This is how the trace record is structured and will
  *	* be saved into the ring buffer. These are the fields
  *	* that will be exposed to user-space in
- *	* /sys/kernel/debug/tracing/events/<*>/format.
+ *	* /sys/kernel/tracing/events/<*>/format.
  *	*
  *	* The declared 'local variable' is called '__entry'
  *	*
@@ -531,7 +531,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
  * tracepoint callback (this is used by programmatic plugins and
  * can also by used by generic instrumentation like SystemTap), and
  * it is also used to expose a structured trace record in
- * /sys/kernel/debug/tracing/events/.
+ * /sys/kernel/tracing/events/.
  *
  * A set of (un)registration functions can be passed to the variant
  * TRACE_EVENT_FN to perform any (un)registration work.
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d7043043f59c..5f5e64f9e715 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -239,7 +239,7 @@ config DYNAMIC_FTRACE
 	  enabled, and the functions not enabled will not affect
 	  performance of the system.
 
-	  See the files in /sys/kernel/debug/tracing:
+	  See the files in /sys/kernel/tracing:
 	    available_filter_functions
 	    set_ftrace_filter
 	    set_ftrace_notrace
@@ -299,7 +299,7 @@ config STACK_TRACER
 	select KALLSYMS
 	help
 	  This special tracer records the maximum stack footprint of the
-	  kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
+	  kernel and displays it in /sys/kernel/tracing/stack_trace.
 
 	  This tracer works by hooking into every function call that the
 	  kernel executes, and keeping a maximum stack depth value and
@@ -339,7 +339,7 @@ config IRQSOFF_TRACER
 	  disabled by default and can be runtime (re-)started
 	  via:
 
-	      echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
+	      echo 0 > /sys/kernel/tracing/tracing_max_latency
 
 	  (Note that kernel size and overhead increase with this option
 	  enabled. This option and the preempt-off timing option can be
@@ -363,7 +363,7 @@ config PREEMPT_TRACER
 	  disabled by default and can be runtime (re-)started
 	  via:
 
-	      echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
+	      echo 0 > /sys/kernel/tracing/tracing_max_latency
 
 	  (Note that kernel size and overhead increase with this option
 	  enabled. This option and the irqs-off timing option can be
@@ -515,7 +515,7 @@ config TRACER_SNAPSHOT
 	  Allow tracing users to take snapshot of the current buffer using the
 	  ftrace interface, e.g.:
 
-	      echo 1 > /sys/kernel/debug/tracing/snapshot
+	      echo 1 > /sys/kernel/tracing/snapshot
 	      cat snapshot
 
 config TRACER_SNAPSHOT_PER_CPU_SWAP
@@ -527,7 +527,7 @@ config TRACER_SNAPSHOT_PER_CPU_SWAP
 	  full swap (all buffers). If this is set, then the following is
 	  allowed:
 
-	      echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
+	      echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot
 
 	  After which, only the tracing buffer for CPU 2 was swapped with
 	  the main tracing buffer, and the other CPU buffers remain the same.
@@ -574,7 +574,7 @@ config PROFILE_ANNOTATED_BRANCHES
 	  This tracer profiles all likely and unlikely macros
 	  in the kernel. It will display the results in:
 
-	  /sys/kernel/debug/tracing/trace_stat/branch_annotated
+	  /sys/kernel/tracing/trace_stat/branch_annotated
 
 	  Note: this will add a significant overhead; only turn this
 	  on if you need to profile the system's use of these macros.
@@ -587,7 +587,7 @@ config PROFILE_ALL_BRANCHES
 	  taken in the kernel is recorded whether it hit or miss.
 	  The results will be displayed in:
 
-	  /sys/kernel/debug/tracing/trace_stat/branch_all
+	  /sys/kernel/tracing/trace_stat/branch_all
 
 	  This option also enables the likely/unlikely profiler.
 
@@ -638,8 +638,8 @@ config BLK_DEV_IO_TRACE
 	  Tracing also is possible using the ftrace interface, e.g.:
 
 	    echo 1 > /sys/block/sda/sda1/trace/enable
-	    echo blk > /sys/kernel/debug/tracing/current_tracer
-	    cat /sys/kernel/debug/tracing/trace_pipe
+	    echo blk > /sys/kernel/tracing/current_tracer
+	    cat /sys/kernel/tracing/trace_pipe
 
 	  If unsure, say N.
 
diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
index c736487fc0e4..4850fdfe27f1 100644
--- a/kernel/trace/kprobe_event_gen_test.c
+++ b/kernel/trace/kprobe_event_gen_test.c
@@ -21,7 +21,7 @@
  * Then:
  *
  * # insmod kernel/trace/kprobe_event_gen_test.ko
- * # cat /sys/kernel/debug/tracing/trace
+ * # cat /sys/kernel/tracing/trace
  *
  * You should see many instances of the "gen_kprobe_test" and
  * "gen_kretprobe_test" events in the trace buffer.
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 45d4a23d6044..071184324d18 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2886,7 +2886,7 @@ rb_check_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
 		  sched_clock_stable() ? "" :
 		  "If you just came from a suspend/resume,\n"
 		  "please switch to the trace global clock:\n"
-		  "  echo global > /sys/kernel/debug/tracing/trace_clock\n"
+		  "  echo global > /sys/kernel/tracing/trace_clock\n"
 		  "or add trace_clock=global to the kernel command line\n");
 }
 
diff --git a/kernel/trace/synth_event_gen_test.c b/kernel/trace/synth_event_gen_test.c
index 8d77526892f4..8dfe85499d4a 100644
--- a/kernel/trace/synth_event_gen_test.c
+++ b/kernel/trace/synth_event_gen_test.c
@@ -22,7 +22,7 @@
  * Then:
  *
  * # insmod kernel/trace/synth_event_gen_test.ko
- * # cat /sys/kernel/debug/tracing/trace
+ * # cat /sys/kernel/tracing/trace
  *
  * You should see several events in the trace buffer -
  * "create_synth_test", "empty_synth_test", and several instances of
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 97c88711f270..fbb602a8b64b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1187,7 +1187,7 @@ void tracing_snapshot_instance(struct trace_array *tr)
  *
  * Note, make sure to allocate the snapshot with either
  * a tracing_snapshot_alloc(), or by doing it manually
- * with: echo 1 > /sys/kernel/debug/tracing/snapshot
+ * with: echo 1 > /sys/kernel/tracing/snapshot
  *
  * If the snapshot buffer is not allocated, it will stop tracing.
  * Basically making a permanent snapshot.
diff --git a/samples/user_events/example.c b/samples/user_events/example.c
index d06dc24156ec..18e34c9d708e 100644
--- a/samples/user_events/example.c
+++ b/samples/user_events/example.c
@@ -23,8 +23,8 @@
 #endif
 
 /* Assumes debugfs is mounted */
-const char *data_file = "/sys/kernel/debug/tracing/user_events_data";
-const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
+const char *data_file = "/sys/kernel/tracing/user_events_data";
+const char *status_file = "/sys/kernel/tracing/user_events_status";
 
 static int event_status(long **status)
 {
diff --git a/scripts/tracing/draw_functrace.py b/scripts/tracing/draw_functrace.py
index 438516bdfb3c..42fa87300941 100755
--- a/scripts/tracing/draw_functrace.py
+++ b/scripts/tracing/draw_functrace.py
@@ -12,9 +12,9 @@ calls. Only the functions's names and the call time are provided.
 
 Usage:
 	Be sure that you have CONFIG_FUNCTION_TRACER
-	# mount -t debugfs nodev /sys/kernel/debug
-	# echo function > /sys/kernel/debug/tracing/current_tracer
-	$ cat /sys/kernel/debug/tracing/trace_pipe > ~/raw_trace_func
+	# mount -t tracefs nodev /sys/kernel/tracing
+	# echo function > /sys/kernel/tracing/current_tracer
+	$ cat /sys/kernel/tracing/trace_pipe > ~/raw_trace_func
 	Wait some times but not too much, the script is a bit slow.
 	Break the pipe (Ctrl + Z)
 	$ scripts/tracing/draw_functrace.py < ~/raw_trace_func > draw_functrace
diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c
index b8e457c841ab..7ba3e81274e8 100644
--- a/tools/lib/api/fs/tracing_path.c
+++ b/tools/lib/api/fs/tracing_path.c
@@ -14,8 +14,8 @@
 #include "tracing_path.h"
 
 static char tracing_mnt[PATH_MAX]  = "/sys/kernel/debug";
-static char tracing_path[PATH_MAX]        = "/sys/kernel/debug/tracing";
-static char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events";
+static char tracing_path[PATH_MAX]        = "/sys/kernel/tracing";
+static char tracing_events_path[PATH_MAX] = "/sys/kernel/tracing/events";
 
 static void __tracing_path_set(const char *tracing, const char *mountpoint)
 {
diff --git a/tools/tracing/latency/latency-collector.c b/tools/tracing/latency/latency-collector.c
index 59a7f2346eab..0fd9c747d396 100644
--- a/tools/tracing/latency/latency-collector.c
+++ b/tools/tracing/latency/latency-collector.c
@@ -1584,7 +1584,7 @@ static void *do_printloop(void *arg)
 		/*
 		 * Toss a coin to decide if we want to sleep before printing
 		 * out the backtrace. The reason for this is that opening
-		 * /sys/kernel/debug/tracing/trace will cause a blackout of
+		 * /sys/kernel/tracing/trace will cause a blackout of
 		 * hundreds of ms, where no latencies will be noted by the
 		 * latency tracer. Thus by randomly sleeping we try to avoid
 		 * missing traces systematically due to this. With this option
-- 
2.39.1

[for-next][PATCH 2/3] tracepoint: Allow livepatch module add trace event

[Steven Rostedt]

From: Jianlin Lv <iecedge@gmail.com>

In the case of keeping the system running, the preferred method for
tracing the kernel is dynamic tracing (kprobe), but the drawback of
this method is that events are lost, especially when tracing packages
in the network stack.

Livepatching provides a potential solution, which is to reimplement the
function you want to replace and insert a static tracepoint.
In such a way, custom stable static tracepoints can be expanded without
rebooting the system.

Link: https://lkml.kernel.org/r/20221102160236.11696-1-iecedge@gmail.com

Signed-off-by: Jianlin Lv <iecedge@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/tracepoint.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index f23144af5743..8d1507dd0724 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -571,8 +571,8 @@ static void for_each_tracepoint_range(
 bool trace_module_has_bad_taint(struct module *mod)
 {
 	return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
-			       (1 << TAINT_UNSIGNED_MODULE) |
-			       (1 << TAINT_TEST));
+				(1 << TAINT_UNSIGNED_MODULE) | (1 << TAINT_TEST) |
+				(1 << TAINT_LIVEPATCH));
 }
 
 static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
-- 
2.39.1

[for-next][PATCH 3/3] tracing: Remove unnecessary NULL assignment

[Steven Rostedt]

From: Wang ShaoBo <bobo.shaobowang@huawei.com>

Remove unnecessary NULL assignment int create_new_subsystem().

Link: https://lkml.kernel.org/r/20221123065124.3982439-1-bobo.shaobowang@huawei.com

Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index cf3fd74fa675..b52c4d79eb78 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2261,8 +2261,6 @@ create_new_subsystem(const char *name)
 	if (!system->name)
 		goto out_free;
 
-	system->filter = NULL;
-
 	system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
 	if (!system->filter)
 		goto out_free;
-- 
2.39.1