[for-next][PATCH 00/10] tracing: Updates for 6.15

[for-next][PATCH 00/10] tracing: Updates for 6.15

[Steven Rostedt]

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

Head SHA1: 25a5153c91ad23effc44dd349bea749f30208d45


Christophe JAILLET (1):
      tracing: Constify struct event_trigger_ops

Douglas Raillard (3):
      tracing: Align synth event print fmt
      tracing: Ensure module defining synth event cannot be unloaded while tracing
      tracing: Fix synth event printk format for str fields

Gabriele Paoloni (1):
      tracing: fix return value in __ftrace_event_enable_disable for TRACE_REG_UNREGISTER

Huang Shijie (1):
      tracepoint: Print the function symbol when tracepoint_debug is set

Petr Mladek (1):
      tracing: gfp: vsprintf: Do not print "none" when using %pGg printf format

Ran Xiaokai (1):
      tracing/osnoise: Fix possible recursive locking for cpus_read_lock()

Sasha Levin (1):
      tracing: Use hashtable.h for event_hash

Steven Rostedt (1):
      scripts/tracing: Remove scripts/tracing/draw_functrace.py

----
 include/trace/events/mmflags.h      |   2 +-
 kernel/trace/trace.h                |   4 +-
 kernel/trace/trace_eprobe.c         |   6 +-
 kernel/trace/trace_events.c         |   4 +-
 kernel/trace/trace_events_hist.c    |  20 +++---
 kernel/trace/trace_events_synth.c   |  35 +++++++++-
 kernel/trace/trace_events_trigger.c |  38 +++++------
 kernel/trace/trace_osnoise.c        |   1 -
 kernel/trace/trace_output.c         |  19 ++----
 kernel/tracepoint.c                 |   2 +-
 scripts/tracing/draw_functrace.py   | 129 ------------------------------------
 11 files changed, 78 insertions(+), 182 deletions(-)
 delete mode 100755 scripts/tracing/draw_functrace.py

[for-next][PATCH 01/10] scripts/tracing: Remove scripts/tracing/draw_functrace.py

[Steven Rostedt]

From: Steven Rostedt <rostedt@goodmis.org>

The draw_functrace.py hasn't worked in years. There's better ways to
accomplish the same thing (via libtracefs). Remove it.

Link: https://lore.kernel.org/linux-trace-kernel/20250210-debuginfo-v1-1-368feb58292a@purestorage.com/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Uday Shankar <ushankar@purestorage.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/20250307103941.070654e7@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 scripts/tracing/draw_functrace.py | 129 ------------------------------
 1 file changed, 129 deletions(-)
 delete mode 100755 scripts/tracing/draw_functrace.py

diff --git a/scripts/tracing/draw_functrace.py b/scripts/tracing/draw_functrace.py
deleted file mode 100755
index 42fa87300941..000000000000
--- a/scripts/tracing/draw_functrace.py
+++ /dev/null
@@ -1,129 +0,0 @@
-#!/usr/bin/env python
-# SPDX-License-Identifier: GPL-2.0-only
-
-"""
-Copyright 2008 (c) Frederic Weisbecker <fweisbec@gmail.com>
-
-This script parses a trace provided by the function tracer in
-kernel/trace/trace_functions.c
-The resulted trace is processed into a tree to produce a more human
-view of the call stack by drawing textual but hierarchical tree of
-calls. Only the functions's names and the call time are provided.
-
-Usage:
-	Be sure that you have CONFIG_FUNCTION_TRACER
-	# 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
-	Then you have your drawn trace in draw_functrace
-"""
-
-
-import sys, re
-
-class CallTree:
-	""" This class provides a tree representation of the functions
-		call stack. If a function has no parent in the kernel (interrupt,
-		syscall, kernel thread...) then it is attached to a virtual parent
-		called ROOT.
-	"""
-	ROOT = None
-
-	def __init__(self, func, time = None, parent = None):
-		self._func = func
-		self._time = time
-		if parent is None:
-			self._parent = CallTree.ROOT
-		else:
-			self._parent = parent
-		self._children = []
-
-	def calls(self, func, calltime):
-		""" If a function calls another one, call this method to insert it
-			into the tree at the appropriate place.
-			@return: A reference to the newly created child node.
-		"""
-		child = CallTree(func, calltime, self)
-		self._children.append(child)
-		return child
-
-	def getParent(self, func):
-		""" Retrieve the last parent of the current node that
-			has the name given by func. If this function is not
-			on a parent, then create it as new child of root
-			@return: A reference to the parent.
-		"""
-		tree = self
-		while tree != CallTree.ROOT and tree._func != func:
-			tree = tree._parent
-		if tree == CallTree.ROOT:
-			child = CallTree.ROOT.calls(func, None)
-			return child
-		return tree
-
-	def __repr__(self):
-		return self.__toString("", True)
-
-	def __toString(self, branch, lastChild):
-		if self._time is not None:
-			s = "%s----%s (%s)\n" % (branch, self._func, self._time)
-		else:
-			s = "%s----%s\n" % (branch, self._func)
-
-		i = 0
-		if lastChild:
-			branch = branch[:-1] + " "
-		while i < len(self._children):
-			if i != len(self._children) - 1:
-				s += "%s" % self._children[i].__toString(branch +\
-								"    |", False)
-			else:
-				s += "%s" % self._children[i].__toString(branch +\
-								"    |", True)
-			i += 1
-		return s
-
-class BrokenLineException(Exception):
-	"""If the last line is not complete because of the pipe breakage,
-	   we want to stop the processing and ignore this line.
-	"""
-	pass
-
-class CommentLineException(Exception):
-	""" If the line is a comment (as in the beginning of the trace file),
-	    just ignore it.
-	"""
-	pass
-
-
-def parseLine(line):
-	line = line.strip()
-	if line.startswith("#"):
-		raise CommentLineException
-	m = re.match("[^]]+?\\] +([a-z.]+) +([0-9.]+): (\\w+) <-(\\w+)", line)
-	if m is None:
-		raise BrokenLineException
-	return (m.group(2), m.group(3), m.group(4))
-
-
-def main():
-	CallTree.ROOT = CallTree("Root (Nowhere)", None, None)
-	tree = CallTree.ROOT
-
-	for line in sys.stdin:
-		try:
-			calltime, callee, caller = parseLine(line)
-		except BrokenLineException:
-			break
-		except CommentLineException:
-			continue
-		tree = tree.getParent(caller)
-		tree = tree.calls(callee, calltime)
-
-	print(CallTree.ROOT)
-
-if __name__ == "__main__":
-	main()
-- 
2.47.2

[for-next][PATCH 02/10] tracing: Constify struct event_trigger_ops

[Steven Rostedt]

From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

'event_trigger_ops mwifiex_if_ops' are not modified in these drivers.

Constifying these structures moves some data to a read-only section, so
increase overall security, especially when the structure holds some
function pointers.

On a x86_64, with allmodconfig, as an example:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  31368	   9024	   6200	  46592	   b600	kernel/trace/trace_events_trigger.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  31752	   8608	   6200	  46560	   b5e0	kernel/trace/trace_events_trigger.o

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/66e8f990e649678e4be37d4d1a19158ca0dea2f4.1741521295.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace.h                |  4 +--
 kernel/trace/trace_eprobe.c         |  6 ++---
 kernel/trace/trace_events_hist.c    | 20 +++++++--------
 kernel/trace/trace_events_trigger.c | 38 ++++++++++++++---------------
 4 files changed, 34 insertions(+), 34 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9c21ba45b7af..880cf9abc055 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1714,7 +1714,7 @@ struct event_trigger_data {
 	unsigned long			count;
 	int				ref;
 	int				flags;
-	struct event_trigger_ops	*ops;
+	const struct event_trigger_ops	*ops;
 	struct event_command		*cmd_ops;
 	struct event_filter __rcu	*filter;
 	char				*filter_str;
@@ -1959,7 +1959,7 @@ struct event_command {
 	int			(*set_filter)(char *filter_str,
 					      struct event_trigger_data *data,
 					      struct trace_event_file *file);
-	struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
+	const struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
 };
 
 /**
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 82fd637cfc19..c1cc2fe54887 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -478,7 +478,7 @@ static void eprobe_trigger_func(struct event_trigger_data *data,
 	__eprobe_trace_func(edata, rec);
 }
 
-static struct event_trigger_ops eprobe_trigger_ops = {
+static const struct event_trigger_ops eprobe_trigger_ops = {
 	.trigger		= eprobe_trigger_func,
 	.print			= eprobe_trigger_print,
 	.init			= eprobe_trigger_init,
@@ -507,8 +507,8 @@ static void eprobe_trigger_unreg_func(char *glob,
 
 }
 
-static struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd,
-							char *param)
+static const struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd,
+							      char *param)
 {
 	return &eprobe_trigger_ops;
 }
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 261163b00137..d3c4880fa8b1 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -6191,7 +6191,7 @@ static void event_hist_trigger_free(struct event_trigger_data *data)
 	}
 }
 
-static struct event_trigger_ops event_hist_trigger_ops = {
+static const struct event_trigger_ops event_hist_trigger_ops = {
 	.trigger		= event_hist_trigger,
 	.print			= event_hist_trigger_print,
 	.init			= event_hist_trigger_init,
@@ -6223,15 +6223,15 @@ static void event_hist_trigger_named_free(struct event_trigger_data *data)
 	}
 }
 
-static struct event_trigger_ops event_hist_trigger_named_ops = {
+static const struct event_trigger_ops event_hist_trigger_named_ops = {
 	.trigger		= event_hist_trigger,
 	.print			= event_hist_trigger_print,
 	.init			= event_hist_trigger_named_init,
 	.free			= event_hist_trigger_named_free,
 };
 
-static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
-							    char *param)
+static const struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
+								  char *param)
 {
 	return &event_hist_trigger_ops;
 }
@@ -6826,38 +6826,38 @@ hist_enable_count_trigger(struct event_trigger_data *data,
 	hist_enable_trigger(data, buffer, rec, event);
 }
 
-static struct event_trigger_ops hist_enable_trigger_ops = {
+static const struct event_trigger_ops hist_enable_trigger_ops = {
 	.trigger		= hist_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops hist_enable_count_trigger_ops = {
+static const struct event_trigger_ops hist_enable_count_trigger_ops = {
 	.trigger		= hist_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops hist_disable_trigger_ops = {
+static const struct event_trigger_ops hist_disable_trigger_ops = {
 	.trigger		= hist_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops hist_disable_count_trigger_ops = {
+static const struct event_trigger_ops hist_disable_count_trigger_ops = {
 	.trigger		= hist_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 hist_enable_get_trigger_ops(char *cmd, char *param)
 {
-	struct event_trigger_ops *ops;
+	const struct event_trigger_ops *ops;
 	bool enable;
 
 	enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d45448947094..b66b6d235d91 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -825,7 +825,7 @@ struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
 					       void *private_data)
 {
 	struct event_trigger_data *trigger_data;
-	struct event_trigger_ops *trigger_ops;
+	const struct event_trigger_ops *trigger_ops;
 
 	trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
 
@@ -1367,38 +1367,38 @@ traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
 				   data->filter_str);
 }
 
-static struct event_trigger_ops traceon_trigger_ops = {
+static const struct event_trigger_ops traceon_trigger_ops = {
 	.trigger		= traceon_trigger,
 	.print			= traceon_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops traceon_count_trigger_ops = {
+static const struct event_trigger_ops traceon_count_trigger_ops = {
 	.trigger		= traceon_count_trigger,
 	.print			= traceon_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops traceoff_trigger_ops = {
+static const struct event_trigger_ops traceoff_trigger_ops = {
 	.trigger		= traceoff_trigger,
 	.print			= traceoff_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops traceoff_count_trigger_ops = {
+static const struct event_trigger_ops traceoff_count_trigger_ops = {
 	.trigger		= traceoff_count_trigger,
 	.print			= traceoff_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 onoff_get_trigger_ops(char *cmd, char *param)
 {
-	struct event_trigger_ops *ops;
+	const struct event_trigger_ops *ops;
 
 	/* we register both traceon and traceoff to this callback */
 	if (strcmp(cmd, "traceon") == 0)
@@ -1491,21 +1491,21 @@ snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
 				   data->filter_str);
 }
 
-static struct event_trigger_ops snapshot_trigger_ops = {
+static const struct event_trigger_ops snapshot_trigger_ops = {
 	.trigger		= snapshot_trigger,
 	.print			= snapshot_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops snapshot_count_trigger_ops = {
+static const struct event_trigger_ops snapshot_count_trigger_ops = {
 	.trigger		= snapshot_count_trigger,
 	.print			= snapshot_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 snapshot_get_trigger_ops(char *cmd, char *param)
 {
 	return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
@@ -1586,21 +1586,21 @@ stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
 				   data->filter_str);
 }
 
-static struct event_trigger_ops stacktrace_trigger_ops = {
+static const struct event_trigger_ops stacktrace_trigger_ops = {
 	.trigger		= stacktrace_trigger,
 	.print			= stacktrace_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops stacktrace_count_trigger_ops = {
+static const struct event_trigger_ops stacktrace_count_trigger_ops = {
 	.trigger		= stacktrace_count_trigger,
 	.print			= stacktrace_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 stacktrace_get_trigger_ops(char *cmd, char *param)
 {
 	return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
@@ -1711,28 +1711,28 @@ void event_enable_trigger_free(struct event_trigger_data *data)
 	}
 }
 
-static struct event_trigger_ops event_enable_trigger_ops = {
+static const struct event_trigger_ops event_enable_trigger_ops = {
 	.trigger		= event_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops event_enable_count_trigger_ops = {
+static const struct event_trigger_ops event_enable_count_trigger_ops = {
 	.trigger		= event_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops event_disable_trigger_ops = {
+static const struct event_trigger_ops event_disable_trigger_ops = {
 	.trigger		= event_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops event_disable_count_trigger_ops = {
+static const struct event_trigger_ops event_disable_count_trigger_ops = {
 	.trigger		= event_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
@@ -1916,10 +1916,10 @@ void event_enable_unregister_trigger(char *glob,
 		data->ops->free(data);
 }
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 event_enable_get_trigger_ops(char *cmd, char *param)
 {
-	struct event_trigger_ops *ops;
+	const struct event_trigger_ops *ops;
 	bool enable;
 
 #ifdef CONFIG_HIST_TRIGGERS
-- 
2.47.2

[for-next][PATCH 03/10] tracepoint: Print the function symbol when tracepoint_debug is set

[Steven Rostedt]

From: Huang Shijie <shijie@os.amperecomputing.com>

When tracepoint_debug is set, we may get the output in kernel log:
     [  380.013843] Probe 0 : 00000000f0d68cda

It is not readable, so change to print the function symbol.
After this patch, the output may becomes:
     [   55.225555] Probe 0 : perf_trace_sched_wakeup_template+0x0/0x20

Link: https://lore.kernel.org/20250307033858.4134-1-shijie@os.amperecomputing.com
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/tracepoint.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 1848ce7e2976..62719d2941c9 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -127,7 +127,7 @@ static void debug_print_probes(struct tracepoint_func *funcs)
 		return;
 
 	for (i = 0; funcs[i].func; i++)
-		printk(KERN_DEBUG "Probe %d : %p\n", i, funcs[i].func);
+		printk(KERN_DEBUG "Probe %d : %pSb\n", i, funcs[i].func);
 }
 
 static struct tracepoint_func *
-- 
2.47.2

[for-next][PATCH 04/10] tracing: gfp: vsprintf: Do not print "none" when using %pGg printf format

[Steven Rostedt]

From: Petr Mladek <pmladek@suse.com>

The commit ca29a0bf122145 ("tracing: gfp: Remove duplication of recording
GFP flags") caused the following regression in printf_test selftest:

[   46.208199] test_printf: kvasprintf(..., "%pGg", ...) returned 'none|0xfc000000', expected '0xfc000000'
[   46.208209] test_printf: kvasprintf(..., "%pGg", ...) returned '__GFP_HIGH|none|0xfc000000', expected '__GFP_HIGH|0xfc000000'

The problem is the new '{ 0, "none" }' entry in __def_gfpflag_names macro
and the following code:

char *format_flags(char *buf, char *end, unsigned long flags,
					const struct trace_print_flags *names)
{
[...]
		if ((flags & mask) != mask)
			continue;
[...]
}

The purpose of the code is to print the name of a mask instead of bits,
for example, printk "GFP_ZONEMASK", instead of
"__GFP_DMA|__GFP_HIGHMEM|__GFP_DMA32|__GFP_MOVABLE".

Unfortunately, the mask "0" pass this check and "none" is always
printed.

A solution would be to move TRACE_GFP_FLAGS up so that it is not
the last entry. But it breaks the rule that named masks must
be defined before names of single bytes. Otherwise, it would
print the names of the bytes instead of the mask.

Instead, replace '{ 0, "none" }' with '{ 0, NULL }'. It works because
__def_gfpflag_names defines a standalone array and this is the standard
trailing entry. The code processing these arrays always ends the cycle
when flag->name == NULL.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Veronika Molnarova <vmolnaro@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Tamir Duberstein <tamird@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/Z9Q5d11ZbA3CNMZm@pathway.suse.cz
Fixes: ca29a0bf122145 ("tracing: gfp: Remove duplication of recording GFP flags")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/events/mmflags.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 82371177ef79..15aae955a10b 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -101,7 +101,7 @@ TRACE_DEFINE_ENUM(___GFP_LAST_BIT);
 	gfpflag_string(GFP_DMA32),		\
 	gfpflag_string(__GFP_RECLAIM),		\
 	TRACE_GFP_FLAGS				\
-	{ 0, "none" }
+	{ 0, NULL }
 
 #define show_gfp_flags(flags)						\
 	(flags) ? __print_flags(flags, "|", __def_gfpflag_names		\
-- 
2.47.2

[for-next][PATCH 05/10] tracing: Use hashtable.h for event_hash

[Steven Rostedt]

From: Sasha Levin <sashal@kernel.org>

Convert the event_hash array in trace_output.c to use the generic
hashtable implementation from hashtable.h instead of the manually
implemented hash table.

This simplifies the code and makes it more maintainable by using the
standard hashtable API defined in hashtable.h.

Rename EVENT_HASHSIZE to EVENT_HASH_BITS to properly reflect its new
meaning as the number of bits for the hashtable size.

Link: https://lore.kernel.org/20250319190545.3058319-1-sashal@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_output.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 03d56f711ad1..3144d020e6c6 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -12,15 +12,16 @@
 #include <linux/sched/clock.h>
 #include <linux/sched/mm.h>
 #include <linux/idr.h>
+#include <linux/hashtable.h>
 
 #include "trace_output.h"
 
-/* must be a power of 2 */
-#define EVENT_HASHSIZE	128
+/* 2^7 = 128 */
+#define EVENT_HASH_BITS 7
 
 DECLARE_RWSEM(trace_event_sem);
 
-static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
+static DEFINE_HASHTABLE(event_hash, EVENT_HASH_BITS);
 
 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
 {
@@ -694,11 +695,8 @@ int trace_print_lat_context(struct trace_iterator *iter)
 struct trace_event *ftrace_find_event(int type)
 {
 	struct trace_event *event;
-	unsigned key;
 
-	key = type & (EVENT_HASHSIZE - 1);
-
-	hlist_for_each_entry(event, &event_hash[key], node) {
+	hash_for_each_possible(event_hash, event, node, type) {
 		if (event->type == type)
 			return event;
 	}
@@ -753,7 +751,6 @@ void trace_event_read_unlock(void)
  */
 int register_trace_event(struct trace_event *event)
 {
-	unsigned key;
 	int ret = 0;
 
 	down_write(&trace_event_sem);
@@ -786,9 +783,7 @@ int register_trace_event(struct trace_event *event)
 	if (event->funcs->binary == NULL)
 		event->funcs->binary = trace_nop_print;
 
-	key = event->type & (EVENT_HASHSIZE - 1);
-
-	hlist_add_head(&event->node, &event_hash[key]);
+	hash_add(event_hash, &event->node, event->type);
 
 	ret = event->type;
  out:
@@ -803,7 +798,7 @@ EXPORT_SYMBOL_GPL(register_trace_event);
  */
 int __unregister_trace_event(struct trace_event *event)
 {
-	hlist_del(&event->node);
+	hash_del(&event->node);
 	free_trace_event_type(event->type);
 	return 0;
 }
-- 
2.47.2

Re: [for-next][PATCH 05/10] tracing: Use hashtable.h for event_hash

[Steven Rostedt]

When I ran my scripts to merge all my topic branches, this one has a
slight conflict with the ftrace branch that adds function arguments to
the function and function graph tracer. As this is mostly a clean up,
I'm going to remove this patch and save it for the next merge window.

Sasha, could you just rebase this on my for-next branch for the repo in
the MAINTAINERS file?

-- Steve


On Sun, 23 Mar 2025 08:29:38 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: Sasha Levin <sashal@kernel.org>
> 
> Convert the event_hash array in trace_output.c to use the generic
> hashtable implementation from hashtable.h instead of the manually
> implemented hash table.
> 
> This simplifies the code and makes it more maintainable by using the
> standard hashtable API defined in hashtable.h.
> 
> Rename EVENT_HASHSIZE to EVENT_HASH_BITS to properly reflect its new
> meaning as the number of bits for the hashtable size.
> 
> Link: https://lore.kernel.org/20250319190545.3058319-1-sashal@kernel.org
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>  kernel/trace/trace_output.c | 19 +++++++------------
>  1 file changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index 03d56f711ad1..3144d020e6c6 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -12,15 +12,16 @@
>  #include <linux/sched/clock.h>
>  #include <linux/sched/mm.h>
>  #include <linux/idr.h>
> +#include <linux/hashtable.h>
>  
>  #include "trace_output.h"
>  
> -/* must be a power of 2 */
> -#define EVENT_HASHSIZE	128
> +/* 2^7 = 128 */
> +#define EVENT_HASH_BITS 7
>  
>  DECLARE_RWSEM(trace_event_sem);
>  
> -static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
> +static DEFINE_HASHTABLE(event_hash, EVENT_HASH_BITS);
>  
>  enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
>  {
> @@ -694,11 +695,8 @@ int trace_print_lat_context(struct trace_iterator *iter)
>  struct trace_event *ftrace_find_event(int type)
>  {
>  	struct trace_event *event;
> -	unsigned key;
>  
> -	key = type & (EVENT_HASHSIZE - 1);
> -
> -	hlist_for_each_entry(event, &event_hash[key], node) {
> +	hash_for_each_possible(event_hash, event, node, type) {
>  		if (event->type == type)
>  			return event;
>  	}
> @@ -753,7 +751,6 @@ void trace_event_read_unlock(void)
>   */
>  int register_trace_event(struct trace_event *event)
>  {
> -	unsigned key;
>  	int ret = 0;
>  
>  	down_write(&trace_event_sem);
> @@ -786,9 +783,7 @@ int register_trace_event(struct trace_event *event)
>  	if (event->funcs->binary == NULL)
>  		event->funcs->binary = trace_nop_print;
>  
> -	key = event->type & (EVENT_HASHSIZE - 1);
> -
> -	hlist_add_head(&event->node, &event_hash[key]);
> +	hash_add(event_hash, &event->node, event->type);
>  
>  	ret = event->type;
>   out:
> @@ -803,7 +798,7 @@ EXPORT_SYMBOL_GPL(register_trace_event);
>   */
>  int __unregister_trace_event(struct trace_event *event)
>  {
> -	hlist_del(&event->node);
> +	hash_del(&event->node);
>  	free_trace_event_type(event->type);
>  	return 0;
>  }

[PATCH] tracing: Use hashtable.h for event_hash

[Sasha Levin]

Convert the event_hash array in trace_output.c to use the generic
hashtable implementation from hashtable.h instead of the manually
implemented hash table.

This simplifies the code and makes it more maintainable by using the
standard hashtable API defined in hashtable.h.

Rename EVENT_HASHSIZE to EVENT_HASH_BITS to properly reflect its new
meaning as the number of bits for the hashtable size.

Link: https://lore.kernel.org/20250319190545.3058319-1-sashal@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/trace_output.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index b51ee93737734..72b699f909e8c 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -14,16 +14,17 @@
 #include <linux/idr.h>
 #include <linux/btf.h>
 #include <linux/bpf.h>
+#include <linux/hashtable.h>
 
 #include "trace_output.h"
 #include "trace_btf.h"
 
-/* must be a power of 2 */
-#define EVENT_HASHSIZE	128
+/* 2^7 = 128 */
+#define EVENT_HASH_BITS 7
 
 DECLARE_RWSEM(trace_event_sem);
 
-static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
+static DEFINE_HASHTABLE(event_hash, EVENT_HASH_BITS);
 
 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
 {
@@ -779,11 +780,8 @@ void print_function_args(struct trace_seq *s, unsigned long *args,
 struct trace_event *ftrace_find_event(int type)
 {
 	struct trace_event *event;
-	unsigned key;
 
-	key = type & (EVENT_HASHSIZE - 1);
-
-	hlist_for_each_entry(event, &event_hash[key], node) {
+	hash_for_each_possible(event_hash, event, node, type) {
 		if (event->type == type)
 			return event;
 	}
@@ -838,7 +836,6 @@ void trace_event_read_unlock(void)
  */
 int register_trace_event(struct trace_event *event)
 {
-	unsigned key;
 	int ret = 0;
 
 	down_write(&trace_event_sem);
@@ -871,9 +868,7 @@ int register_trace_event(struct trace_event *event)
 	if (event->funcs->binary == NULL)
 		event->funcs->binary = trace_nop_print;
 
-	key = event->type & (EVENT_HASHSIZE - 1);
-
-	hlist_add_head(&event->node, &event_hash[key]);
+	hash_add(event_hash, &event->node, event->type);
 
 	ret = event->type;
  out:
@@ -888,7 +883,7 @@ EXPORT_SYMBOL_GPL(register_trace_event);
  */
 int __unregister_trace_event(struct trace_event *event)
 {
-	hlist_del(&event->node);
+	hash_del(&event->node);
 	free_trace_event_type(event->type);
 	return 0;
 }

base-commit: cac258af1363995736fd0d62f80b37e0937ded3f
-- 
2.39.5

[for-next][PATCH 06/10] tracing: Align synth event print fmt

[Steven Rostedt]

From: Douglas Raillard <douglas.raillard@arm.com>

The vast majority of ftrace event print fmt consist of a space-separated
field=value pair. Synthetic event currently use a comma-separated
field=value pair, which sticks out from events created via more
classical means.

Align the format of synth events so they look just like any other event,
for better consistency and less headache when doing crude text-based
data processing.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250319215028.1680278-1-douglas.raillard@arm.com
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_synth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index e3f7d09e5512..07ff8be8267e 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -612,7 +612,7 @@ static int __set_synth_event_print_fmt(struct synth_event *event,
 		fmt = synth_field_fmt(event->fields[i]->type);
 		pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 				event->fields[i]->name, fmt,
-				i == event->n_fields - 1 ? "" : ", ");
+				i == event->n_fields - 1 ? "" : " ");
 	}
 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 
-- 
2.47.2

[for-next][PATCH 07/10] tracing/osnoise: Fix possible recursive locking for cpus_read_lock()

[Steven Rostedt]

From: Ran Xiaokai <ran.xiaokai@zte.com.cn>

Lockdep reports this deadlock log:

osnoise: could not start sampling thread
============================================
WARNING: possible recursive locking detected
--------------------------------------------
       CPU0
       ----
  lock(cpu_hotplug_lock);
  lock(cpu_hotplug_lock);

 Call Trace:
  <TASK>
  print_deadlock_bug+0x282/0x3c0
  __lock_acquire+0x1610/0x29a0
  lock_acquire+0xcb/0x2d0
  cpus_read_lock+0x49/0x120
  stop_per_cpu_kthreads+0x7/0x60
  start_kthread+0x103/0x120
  osnoise_hotplug_workfn+0x5e/0x90
  process_one_work+0x44f/0xb30
  worker_thread+0x33e/0x5e0
  kthread+0x206/0x3b0
  ret_from_fork+0x31/0x50
  ret_from_fork_asm+0x11/0x20
  </TASK>

This is the deadlock scenario:
osnoise_hotplug_workfn()
  guard(cpus_read_lock)();      // first lock call
  start_kthread(cpu)
    if (IS_ERR(kthread)) {
      stop_per_cpu_kthreads(); {
        cpus_read_lock();      // second lock call. Cause the AA deadlock
      }
    }

It is not necessary to call stop_per_cpu_kthreads() which stops osnoise
kthread for every other CPUs in the system if a failure occurs during
hotplug of a certain CPU.
For start_per_cpu_kthreads(), if the start_kthread() call fails,
this function calls stop_per_cpu_kthreads() to handle the error.
Therefore, similarly, there is no need to call stop_per_cpu_kthreads()
again within start_kthread().
So just remove stop_per_cpu_kthreads() from start_kthread to solve this issue.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250321095249.2739397-1-ranxiaokai627@163.com
Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_osnoise.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index f3a2722ee4c0..c83a51218ee5 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -2032,7 +2032,6 @@ static int start_kthread(unsigned int cpu)
 
 	if (IS_ERR(kthread)) {
 		pr_err(BANNER "could not start sampling thread\n");
-		stop_per_cpu_kthreads();
 		return -ENOMEM;
 	}
 
-- 
2.47.2

[for-next][PATCH 08/10] tracing: fix return value in __ftrace_event_enable_disable for TRACE_REG_UNREGISTER

[Steven Rostedt]

From: Gabriele Paoloni <gpaoloni@redhat.com>

When __ftrace_event_enable_disable invokes the class callback to
unregister the event, the return value is not reported up to the
caller, hence leading to event unregister failures being silently
ignored.

This patch assigns the ret variable to the invocation of the
event unregister callback, so that its return value is stored
and reported to the caller, and it raises a warning in case
of error.

Link: https://lore.kernel.org/20250321170821.101403-1-gpaoloni@redhat.com
Signed-off-by: Gabriele Paoloni <gpaoloni@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 513de9ceb80e..8e7603acca21 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -790,7 +790,9 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
 				clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 			}
 
-			call->class->reg(call, TRACE_REG_UNREGISTER, file);
+			ret = call->class->reg(call, TRACE_REG_UNREGISTER, file);
+
+			WARN_ON_ONCE(ret);
 		}
 		/* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 		if (file->flags & EVENT_FILE_FL_SOFT_MODE)
-- 
2.47.2

[for-next][PATCH 09/10] tracing: Ensure module defining synth event cannot be unloaded while tracing

[Steven Rostedt]

From: Douglas Raillard <douglas.raillard@arm.com>

Currently, using synth_event_delete() will fail if the event is being
used (tracing in progress), but that is normally done in the module exit
function. At that stage, failing is problematic as returning a non-zero
status means the module will become locked (impossible to unload or
reload again).

Instead, ensure the module exit function does not get called in the
first place by increasing the module refcnt when the event is enabled.

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 35ca5207c2d11 ("tracing: Add synthetic event command generation functions")
Link: https://lore.kernel.org/20250318180906.226841-1-douglas.raillard@arm.com
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_synth.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 07ff8be8267e..463b0073629a 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -852,6 +852,34 @@ static struct trace_event_fields synth_event_fields_array[] = {
 	{}
 };
 
+static int synth_event_reg(struct trace_event_call *call,
+		    enum trace_reg type, void *data)
+{
+	struct synth_event *event = container_of(call, struct synth_event, call);
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+	case TRACE_REG_PERF_REGISTER:
+		if (!try_module_get(event->mod))
+			return -EBUSY;
+		break;
+	default:
+		break;
+	}
+
+	int ret = trace_event_reg(call, type, data);
+
+	switch (type) {
+	case TRACE_REG_UNREGISTER:
+	case TRACE_REG_PERF_UNREGISTER:
+		module_put(event->mod);
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
 static int register_synth_event(struct synth_event *event)
 {
 	struct trace_event_call *call = &event->call;
@@ -881,7 +909,7 @@ static int register_synth_event(struct synth_event *event)
 		goto out;
 	}
 	call->flags = TRACE_EVENT_FL_TRACEPOINT;
-	call->class->reg = trace_event_reg;
+	call->class->reg = synth_event_reg;
 	call->class->probe = trace_event_raw_event_synth;
 	call->data = event;
 	call->tp = event->tp;
-- 
2.47.2

[for-next][PATCH 10/10] tracing: Fix synth event printk format for str fields

[Steven Rostedt]

From: Douglas Raillard <douglas.raillard@arm.com>

The printk format for synth event uses "%.*s" to print string fields,
but then only passes the pointer part as var arg.

Add the missing precision var arg.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250318180939.227696-1-douglas.raillard@arm.com
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_synth.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 463b0073629a..d91205bc9f61 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -620,7 +620,8 @@ static int __set_synth_event_print_fmt(struct synth_event *event,
 		if (event->fields[i]->is_string &&
 		    event->fields[i]->is_dynamic)
 			pos += snprintf(buf + pos, LEN_OR_ZERO,
-				", __get_str(%s)", event->fields[i]->name);
+				", (int)__get_dynamic_array_len(%s), __get_str(%s)",
+				event->fields[i]->name, event->fields[i]->name);
 		else if (event->fields[i]->is_stack)
 			pos += snprintf(buf + pos, LEN_OR_ZERO,
 				", __get_stacktrace(%s)", event->fields[i]->name);
-- 
2.47.2