kernel/trace/ftrace.c | 12 ++++++++---- kernel/trace/trace.c | 30 +++++++++++++++++++++++++++++- kernel/trace/trace.h | 2 ++ kernel/trace/trace_events.c | 24 +++++++++++++++++++++--- kernel/trace/trace_kprobe.c | 3 ++- 5 files changed, 62 insertions(+), 9 deletions(-)
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. trace_trigger=
still tokenizes a temporary parse buffer in place, but now copies each
parsed event/trigger pair into boot-time storage so repeated instances
do not overwrite earlier ones.
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.
Signed-off-by: Wesley Atwell <atwellwea@gmail.com>
---
Changes since v5: https://lore.kernel.org/all/20260328201842.1782806-1-atwellwea@gmail.com/
- add the separator accounting comment in trace_append_boot_param()
- keep the existing trace_trigger= temporary buffer and copy each
parsed event/trigger pair into boot-time storage instead of tracking
a running offset inside that buffer
kernel/trace/ftrace.c | 12 ++++++++----
kernel/trace/trace.c | 30 +++++++++++++++++++++++++++++-
kernel/trace/trace.h | 2 ++
kernel/trace/trace_events.c | 24 +++++++++++++++++++++---
kernel/trace/trace_kprobe.c | 3 ++-
5 files changed, 62 insertions(+), 9 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 a626211ceb9a..2fbfcb506b24 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -228,6 +228,33 @@ static int boot_instance_index;
static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
static int boot_snapshot_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);
@@ -329,7 +356,8 @@ 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 b8f3804586a0..237a0417de1c 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -863,6 +863,8 @@ extern int DYN_FTRACE_TEST_NAME(void);
extern int DYN_FTRACE_TEST_NAME2(void);
extern void trace_set_ring_buffer_expanded(struct trace_array *tr);
+void __init trace_append_boot_param(char *buf, const char *str,
+ char sep, int size);
extern bool tracing_selftest_disabled;
#ifdef CONFIG_FTRACE_STARTUP_TEST
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 249d1cba72c0..1c4a4a46169e 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -17,6 +17,7 @@
#include <linux/kthread.h>
#include <linux/tracefs.h>
#include <linux/uaccess.h>
+#include <linux/memblock.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/sort.h>
@@ -3674,7 +3675,7 @@ trace_create_new_event(struct trace_event_call *call,
#define MAX_BOOT_TRIGGERS 32
static struct boot_triggers {
- const char *event;
+ char *event;
char *trigger;
} bootup_triggers[MAX_BOOT_TRIGGERS];
@@ -3683,6 +3684,7 @@ static int nr_boot_triggers;
static __init int setup_trace_triggers(char *str)
{
+ char *event;
char *trigger;
char *buf;
int i;
@@ -3692,14 +3694,30 @@ static __init int setup_trace_triggers(char *str)
disable_tracing_selftest("running event triggers");
buf = bootup_trigger_buf;
- for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
+ for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) {
trigger = strsep(&buf, ",");
if (!trigger)
break;
- bootup_triggers[i].event = strsep(&trigger, ".");
+ event = strsep(&trigger, ".");
bootup_triggers[i].trigger = trigger;
if (!bootup_triggers[i].trigger)
break;
+
+ /*
+ * Keep each parsed trigger outside the temporary setup
+ * buffer so repeated trace_trigger= entries do not
+ * overwrite earlier ones.
+ */
+ bootup_triggers[i].event =
+ memblock_alloc_or_panic(strlen(event) + 1,
+ SMP_CACHE_BYTES);
+ strscpy(bootup_triggers[i].event, event,
+ strlen(event) + 1);
+ bootup_triggers[i].trigger =
+ memblock_alloc_or_panic(strlen(trigger) + 1,
+ SMP_CACHE_BYTES);
+ strscpy(bootup_triggers[i].trigger, trigger,
+ strlen(trigger) + 1);
}
nr_boot_triggers = i;
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;
--
2.43.0On Sun, 29 Mar 2026 12:42:54 -0600
Wesley Atwell <atwellwea@gmail.com> wrote:
BTW, please do not reply to old versions of a patch with new versions. It
makes it much more difficult for maintainers to find what is the last patch.
New versions of a patch should *always* be a start of a new thread!
> 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. trace_trigger=
> still tokenizes a temporary parse buffer in place, but now copies each
> parsed event/trigger pair into boot-time storage so repeated instances
> do not overwrite earlier ones.
>
> 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.
>
> Signed-off-by: Wesley Atwell <atwellwea@gmail.com>
> ---
> Changes since v5: https://lore.kernel.org/all/20260328201842.1782806-1-atwellwea@gmail.com/
This is also why I suggested using the above link. The link shows how to
find the old version of the patch, without relying on "In-Reply-To" header.
> - add the separator accounting comment in trace_append_boot_param()
> - keep the existing trace_trigger= temporary buffer and copy each
> parsed event/trigger pair into boot-time storage instead of tracking
> a running offset inside that buffer
>
> kernel/trace/ftrace.c | 12 ++++++++----
> kernel/trace/trace.c | 30 +++++++++++++++++++++++++++++-
> kernel/trace/trace.h | 2 ++
> kernel/trace/trace_events.c | 24 +++++++++++++++++++++---
> kernel/trace/trace_kprobe.c | 3 ++-
> 5 files changed, 62 insertions(+), 9 deletions(-)
>
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -228,6 +228,33 @@ static int boot_instance_index;
> static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
> static int boot_snapshot_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;
Nit, but it would be nice to have a blank line here.
> + /* 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);
> @@ -329,7 +356,8 @@ 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 b8f3804586a0..237a0417de1c 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -863,6 +863,8 @@ extern int DYN_FTRACE_TEST_NAME(void);
> extern int DYN_FTRACE_TEST_NAME2(void);
>
> extern void trace_set_ring_buffer_expanded(struct trace_array *tr);
> +void __init trace_append_boot_param(char *buf, const char *str,
> + char sep, int size);
> extern bool tracing_selftest_disabled;
>
> #ifdef CONFIG_FTRACE_STARTUP_TEST
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 249d1cba72c0..1c4a4a46169e 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -17,6 +17,7 @@
> #include <linux/kthread.h>
> #include <linux/tracefs.h>
> #include <linux/uaccess.h>
> +#include <linux/memblock.h>
> #include <linux/module.h>
> #include <linux/ctype.h>
> #include <linux/sort.h>
> @@ -3674,7 +3675,7 @@ trace_create_new_event(struct trace_event_call *call,
> #define MAX_BOOT_TRIGGERS 32
>
> static struct boot_triggers {
> - const char *event;
> + char *event;
> char *trigger;
> } bootup_triggers[MAX_BOOT_TRIGGERS];
>
> @@ -3683,6 +3684,7 @@ static int nr_boot_triggers;
>
> static __init int setup_trace_triggers(char *str)
> {
> + char *event;
> char *trigger;
> char *buf;
> int i;
> @@ -3692,14 +3694,30 @@ static __init int setup_trace_triggers(char *str)
> disable_tracing_selftest("running event triggers");
>
> buf = bootup_trigger_buf;
> - for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
> + for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) {
Let's not make this so complex.
This function isn't the same as the other functions. It doesn't need to add
separators to the temp buffer. It only needs to append it.
> trigger = strsep(&buf, ",");
> if (!trigger)
> break;
> - bootup_triggers[i].event = strsep(&trigger, ".");
> + event = strsep(&trigger, ".");
> bootup_triggers[i].trigger = trigger;
> if (!bootup_triggers[i].trigger)
> break;
> +
> + /*
> + * Keep each parsed trigger outside the temporary setup
> + * buffer so repeated trace_trigger= entries do not
> + * overwrite earlier ones.
> + */
> + bootup_triggers[i].event =
> + memblock_alloc_or_panic(strlen(event) + 1,
> + SMP_CACHE_BYTES);
> + strscpy(bootup_triggers[i].event, event,
> + strlen(event) + 1);
> + bootup_triggers[i].trigger =
> + memblock_alloc_or_panic(strlen(trigger) + 1,
> + SMP_CACHE_BYTES);
> + strscpy(bootup_triggers[i].trigger, trigger,
> + strlen(trigger) + 1);
> }
I believe all you need for the boot triggers is this:
(Not even compiled tested)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 9928da636c9d..7754a8adb58a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -3677,20 +3677,24 @@ 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);
+ 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);
+
+ for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) {
trigger = strsep(&buf, ",");
if (!trigger)
break;
On Mon, 30 Mar 2026 10:43:22 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 9928da636c9d..7754a8adb58a 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -3677,20 +3677,24 @@ 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);
> + 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);
The above needs to skip the '\0' too:
boot_trigger_buf_len += strlen(buf) + 1;
> +
> + for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) {
> trigger = strsep(&buf, ",");
> if (!trigger)
> break;
On Mon, 30 Mar 2026 12:37:43 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Mon, 30 Mar 2026 10:43:22 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> > index 9928da636c9d..7754a8adb58a 100644
> > --- a/kernel/trace/trace_events.c
> > +++ b/kernel/trace/trace_events.c
> > @@ -3677,20 +3677,24 @@ 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);
> > + 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);
>
> The above needs to skip the '\0' too:
>
> boot_trigger_buf_len += strlen(buf) + 1;
>
And since this option is different from the rest, lets make it a separate patch.
-- Steve
>
> > +
> > + for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) {
> > trigger = strsep(&buf, ",");
> > if (!trigger)
> > break;
>
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