* [for-next][PATCH 1/3] tracing: Append repeated boot-time tracing parameters
2026-04-01 0:40 [for-next][PATCH 0/3] tracing: Updates for v7.1 Steven Rostedt
@ 2026-04-01 0:40 ` Steven Rostedt
2026-04-01 0:40 ` [for-next][PATCH 2/3] tracing: Preserve repeated trace_trigger boot parameters Steven Rostedt
2026-04-01 0:40 ` [for-next][PATCH 3/3] tracing: Remove duplicate latency_fsnotify() stub Steven Rostedt
2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2026-04-01 0:40 UTC (permalink / raw)
To: linux-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Wesley Atwell
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
^ permalink raw reply related [flat|nested] 4+ messages in thread* [for-next][PATCH 2/3] tracing: Preserve repeated trace_trigger boot parameters
2026-04-01 0:40 [for-next][PATCH 0/3] tracing: Updates for v7.1 Steven Rostedt
2026-04-01 0:40 ` [for-next][PATCH 1/3] tracing: Append repeated boot-time tracing parameters Steven Rostedt
@ 2026-04-01 0:40 ` Steven Rostedt
2026-04-01 0:40 ` [for-next][PATCH 3/3] tracing: Remove duplicate latency_fsnotify() stub Steven Rostedt
2 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2026-04-01 0:40 UTC (permalink / raw)
To: linux-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Wesley Atwell
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
^ permalink raw reply related [flat|nested] 4+ messages in thread