[for-next][PATCH 0/3] tracing: Updates for v7.1

[for-next][PATCH 0/3] tracing: Updates for v7.1

[Steven Rostedt]

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

Head SHA1: 8053f49fed581c40fcc87fa54904f4fa473f46b7


Steven Rostedt (1):
      tracing: Remove duplicate latency_fsnotify() stub

Wesley Atwell (2):
      tracing: Append repeated boot-time tracing parameters
      tracing: Preserve repeated trace_trigger boot parameters

----
 kernel/trace/ftrace.c         | 12 ++++++++----
 kernel/trace/trace.c          | 31 ++++++++++++++++++++++++++++++-
 kernel/trace/trace.h          |  4 +++-
 kernel/trace/trace_events.c   | 13 ++++++++++---
 kernel/trace/trace_kprobe.c   |  3 ++-
 kernel/trace/trace_snapshot.c |  3 +--
 6 files changed, 54 insertions(+), 12 deletions(-)

[for-next][PATCH 1/3] tracing: Append repeated boot-time tracing parameters

[Steven Rostedt]

From: Wesley Atwell <atwellwea@gmail.com>

Some tracing boot parameters already accept delimited value lists, but
their __setup() handlers keep only the last instance seen at boot.
Make repeated instances append to the same boot-time buffer in the
format each parser already consumes.

Use a shared trace_append_boot_param() helper for the ftrace filters,
trace_options, and kprobe_event boot parameters.

This also lets Bootconfig array values work naturally when they expand
to repeated param=value entries.

Before this change, only the last instance from each repeated
parameter survived boot.

Link: https://patch.msgid.link/20260330181103.1851230-1-atwellwea@gmail.com
Signed-off-by: Wesley Atwell <atwellwea@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c       | 12 ++++++++----
 kernel/trace/trace.c        | 31 ++++++++++++++++++++++++++++++-
 kernel/trace/trace.h        |  2 ++
 kernel/trace/trace_kprobe.c |  3 ++-
 4 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 413310912609..8bd3dd1d549c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6841,7 +6841,8 @@ bool ftrace_filter_param __initdata;
 static int __init set_ftrace_notrace(char *str)
 {
 	ftrace_filter_param = true;
-	strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
+	trace_append_boot_param(ftrace_notrace_buf, str, ',',
+				FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_notrace=", set_ftrace_notrace);
@@ -6849,7 +6850,8 @@ __setup("ftrace_notrace=", set_ftrace_notrace);
 static int __init set_ftrace_filter(char *str)
 {
 	ftrace_filter_param = true;
-	strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
+	trace_append_boot_param(ftrace_filter_buf, str, ',',
+				FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_filter=", set_ftrace_filter);
@@ -6861,14 +6863,16 @@ static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
 
 static int __init set_graph_function(char *str)
 {
-	strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
+	trace_append_boot_param(ftrace_graph_buf, str, ',',
+				FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_graph_filter=", set_graph_function);
 
 static int __init set_graph_notrace_function(char *str)
 {
-	strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
+	trace_append_boot_param(ftrace_graph_notrace_buf, str, ',',
+				FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7b9dd6378849..284f813a61f8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -221,6 +221,34 @@ static char *default_bootup_tracer;
 static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
 static int boot_instance_index;
 
+/*
+ * Repeated boot parameters, including Bootconfig array expansions, need
+ * to stay in the delimiter form that the existing parser consumes.
+ */
+void __init trace_append_boot_param(char *buf, const char *str, char sep,
+				    int size)
+{
+	int len, needed, str_len;
+
+	if (!*str)
+		return;
+
+	len = strlen(buf);
+	str_len = strlen(str);
+	needed = len + str_len + 1;
+
+	/* For continuation, account for the separator. */
+	if (len)
+		needed++;
+	if (needed > size)
+		return;
+
+	if (len)
+		buf[len++] = sep;
+
+	strscpy(buf + len, str, size - len);
+}
+
 static int __init set_cmdline_ftrace(char *str)
 {
 	strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
@@ -290,7 +318,8 @@ static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
 
 static int __init set_trace_boot_options(char *str)
 {
-	strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
+	trace_append_boot_param(trace_boot_options_buf, str, ',',
+				MAX_TRACER_SIZE);
 	return 1;
 }
 __setup("trace_options=", set_trace_boot_options);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index a3ea735a9ef6..0904fd356634 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -905,6 +905,8 @@ extern int DYN_FTRACE_TEST_NAME(void);
 #define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2
 extern int DYN_FTRACE_TEST_NAME2(void);
 
+void __init trace_append_boot_param(char *buf, const char *str,
+				    char sep, int size);
 extern void trace_set_ring_buffer_expanded(struct trace_array *tr);
 extern bool tracing_selftest_disabled;
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a5dbb72528e0..e9f1c55aea64 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -31,7 +31,8 @@ static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
 
 static int __init set_kprobe_boot_events(char *str)
 {
-	strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
+	trace_append_boot_param(kprobe_boot_events_buf, str, ';',
+				COMMAND_LINE_SIZE);
 	disable_tracing_selftest("running kprobe events");
 
 	return 1;
-- 
2.51.0

[for-next][PATCH 2/3] tracing: Preserve repeated trace_trigger boot parameters

[Steven Rostedt]

From: Wesley Atwell <atwellwea@gmail.com>

trace_trigger= tokenizes bootup_trigger_buf in place and stores pointers
into that buffer for later trigger registration. Repeated trace_trigger=
parameters overwrite the buffer contents from earlier calls, leaving
only the last set of parsed event and trigger strings.

Keep each new trace_trigger= string at the end of bootup_trigger_buf and
parse only the appended range. That preserves the earlier event and
trigger strings while still letting repeated parameters queue additional
boot-time triggers.

This also lets Bootconfig array values work naturally when they expand
to repeated trace_trigger= entries.

Before this change, only the last trace_trigger= instance survived boot.

Link: https://patch.msgid.link/20260330181103.1851230-2-atwellwea@gmail.com
Signed-off-by: Wesley Atwell <atwellwea@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index de807a9e2371..5df08645396e 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -3675,20 +3675,27 @@ static struct boot_triggers {
 } bootup_triggers[MAX_BOOT_TRIGGERS];
 
 static char bootup_trigger_buf[COMMAND_LINE_SIZE];
+static int boot_trigger_buf_len;
 static int nr_boot_triggers;
 
 static __init int setup_trace_triggers(char *str)
 {
 	char *trigger;
 	char *buf;
+	int len = boot_trigger_buf_len;
 	int i;
 
-	strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
+	if (len >= COMMAND_LINE_SIZE)
+		return 1;
+
+	strscpy(bootup_trigger_buf + len, str, COMMAND_LINE_SIZE - len);
 	trace_set_ring_buffer_expanded(NULL);
 	disable_tracing_selftest("running event triggers");
 
-	buf = bootup_trigger_buf;
-	for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
+	buf = bootup_trigger_buf + len;
+	boot_trigger_buf_len += strlen(buf) + 1;
+
+	for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) {
 		trigger = strsep(&buf, ",");
 		if (!trigger)
 			break;
-- 
2.51.0

[for-next][PATCH 3/3] tracing: Remove duplicate latency_fsnotify() stub

[Steven Rostedt]

From: Steven Rostedt <rostedt@goodmis.org>

When the SNAPSHOT is defined but FSNOTIFY is not the latency_fsnotify()
function is turned into a static inline stub. But this stub was defined in
both trace.h and trace_snapshot.c causing a error in build when
CONFIG_SNAPSHOT is defined but FSNOTIFY is not. The stub is not needed in
trace_snapshot.c as it will be defined in trace.h, remove it from the C
file.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260330205859.24c0aae3@gandalf.local.home
Fixes: bade44fe5462 ("tracing: Move snapshot code out of trace.c and into trace_snapshot.c")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202603310604.lGE9LDBK-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace.h          | 2 +-
 kernel/trace/trace_snapshot.c | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 0904fd356634..90d67f4432f5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -845,13 +845,13 @@ void update_max_tr_single(struct trace_array *tr,
 #if defined(CONFIG_TRACER_MAX_TRACE) && defined(CONFIG_FSNOTIFY)
 # define LATENCY_FS_NOTIFY
 #endif
+#endif /* CONFIG_TRACER_SNAPSHOT */
 
 #ifdef LATENCY_FS_NOTIFY
 void latency_fsnotify(struct trace_array *tr);
 #else
 static inline void latency_fsnotify(struct trace_array *tr) { }
 #endif
-#endif /* CONFIG_TRACER_SNAPSHOT */
 
 #ifdef CONFIG_STACKTRACE
 void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, int skip);
diff --git a/kernel/trace/trace_snapshot.c b/kernel/trace/trace_snapshot.c
index 8865b2ef2264..07b43c9863a2 100644
--- a/kernel/trace/trace_snapshot.c
+++ b/kernel/trace/trace_snapshot.c
@@ -391,9 +391,8 @@ void latency_fsnotify(struct trace_array *tr)
 	 */
 	irq_work_queue(&tr->fsnotify_irqwork);
 }
-#else
-static inline void latency_fsnotify(struct trace_array *tr) { }
 #endif /* LATENCY_FS_NOTIFY */
+
 static const struct file_operations tracing_max_lat_fops;
 
 void trace_create_maxlat_file(struct trace_array *tr,
-- 
2.51.0