Commit 842b74e5 authored by Wesley Atwell's avatar Wesley Atwell Committed by Steven Rostedt (Google)
Browse files

tracing: Append repeated boot-time tracing parameters 

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: default avatarWesley Atwell <atwellwea@gmail.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent e197453e

kernel/trace/ftrace.c

+8 −4
Original line number Diff line number Diff line
@@ -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);

kernel/trace/trace.c

+30 −1
Original line number Diff line number Diff line
@@ -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);

kernel/trace/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

kernel/trace/trace_kprobe.c

+2 −1
Original line number Diff line number Diff line
@@ -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;