Commit 95c104c3 authored by Linyu Yuan's avatar Linyu Yuan Committed by Steven Rostedt (Google)
Browse files

tracing: Auto generate event name when creating a group of events 

Currently when creating a specific group of trace events,
take kprobe event as example, the user must use the following format:
p:GRP/EVENT [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS],
which means user must enter EVENT name, one example is:

  echo 'p:usb_gadget/config_usb_cfg_link config_usb_cfg_link $arg1' >> kprobe_events

It is not simple if there are too many entries because the event name is
the same as symbol name.

This change allows user to specify no EVENT name, format changed as:

   p:GRP/ [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]

It will generate event name automatically and one example is:

  echo 'p:usb_gadget/ config_usb_cfg_link $arg1' >> kprobe_events.

Link: https://lore.kernel.org/all/1656296348-16111-4-git-send-email-quic_linyyuan@quicinc.com/



Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: default avatarTom Zanussi <zanussi@kernel.org>
Signed-off-by: default avatarLinyu Yuan <quic_linyyuan@quicinc.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent f360ea56

Documentation/trace/kprobetrace.rst

+4 −4
Original line number Diff line number Diff line
@@ -28,10 +28,10 @@ Synopsis of kprobe_events 
-------------------------

::



  p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS]	: Set a probe

  r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS]	: Set a return probe

  p:[GRP/]EVENT] [MOD:]SYM[+0]%return [FETCHARGS]	: Set a return probe

  -:[GRP/]EVENT						: Clear a probe

  p[:[GRP/][EVENT]] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS]	: Set a probe

  r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]SYM[+0] [FETCHARGS]	: Set a return probe

  p[:[GRP/][EVENT]] [MOD:]SYM[+0]%return [FETCHARGS]	: Set a return probe

  -:[GRP/][EVENT]						: Clear a probe



 GRP		: Group name. If omitted, use "kprobes" for it.

 EVENT		: Event name. If omitted, the event name is generated

Documentation/trace/uprobetracer.rst

+4 −4
Original line number Diff line number Diff line
@@ -26,10 +26,10 @@ Synopsis of uprobe_tracer 
-------------------------

::



  p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe

  r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)

  p[:[GRP/]EVENT] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)

  -:[GRP/]EVENT                           : Clear uprobe or uretprobe event

  p[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a uprobe

  r[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)

  p[:[GRP/][EVENT]] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)

  -:[GRP/][EVENT]                           : Clear uprobe or uretprobe event



  GRP           : Group name. If omitted, "uprobes" is the default value.

  EVENT         : Event name. If omitted, the event name is generated based

kernel/trace/trace.c

+4 −4
Original line number Diff line number Diff line
@@ -5569,13 +5569,13 @@ static const char readme_msg[] = 
#endif

#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)

	"\t  accepts: event-definitions (one definition per line)\n"

	"\t   Format: p[:[<group>/]<event>] <place> [<args>]\n"

	"\t           r[maxactive][:[<group>/]<event>] <place> [<args>]\n"

	"\t   Format: p[:[<group>/][<event>]] <place> [<args>]\n"

	"\t           r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"

#ifdef CONFIG_HIST_TRIGGERS

	"\t           s:[synthetic/]<event> <field> [<field>]\n"

#endif

	"\t           e[:[<group>/]<event>] <attached-group>.<attached-event> [<args>]\n"

	"\t           -:[<group>/]<event>\n"

	"\t           e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>]\n"

	"\t           -:[<group>/][<event>]\n"

#ifdef CONFIG_KPROBE_EVENTS

	"\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"

  "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"

kernel/trace/trace_dynevent.c

+1 −1
Original line number Diff line number Diff line
@@ -101,7 +101,7 @@ int dyn_event_release(const char *raw_command, struct dyn_event_operations *type 
		event = p + 1;

		*p = '\0';

	}

	if (event[0] == '\0') {

	if (!system && event[0] == '\0') {

		ret = -EINVAL;

		goto out;

	}

kernel/trace/trace_eprobe.c

+13 −12
Original line number Diff line number Diff line
@@ -125,6 +125,7 @@ static bool eprobe_dyn_event_match(const char *system, const char *event, 
	 * We match the following:

	 *  event only			- match all eprobes with event name

	 *  system and event only	- match all system/event probes

	 *  system only			- match all system probes

	 *

	 * The below has the above satisfied with more arguments:

	 *
@@ -143,7 +144,7 @@ static bool eprobe_dyn_event_match(const char *system, const char *event, 
		return false;



	/* Must match the event name */

	if (strcmp(trace_probe_name(&ep->tp), event) != 0)

	if (event[0] != '\0' && strcmp(trace_probe_name(&ep->tp), event) != 0)

		return false;



	/* No arguments match all */
@@ -848,7 +849,7 @@ static int __trace_eprobe_create(int argc, const char *argv[]) 
{

	/*

	 * Argument syntax:

	 *      e[:[GRP/]ENAME] SYSTEM.EVENT [FETCHARGS]

	 *      e[:[GRP/][ENAME]] SYSTEM.EVENT [FETCHARGS]

	 * Fetch args:

	 *  <name>=$<field>[:TYPE]

	 */
@@ -858,6 +859,7 @@ static int __trace_eprobe_create(int argc, const char *argv[]) 
	struct trace_eprobe *ep = NULL;

	char buf1[MAX_EVENT_NAME_LEN];

	char buf2[MAX_EVENT_NAME_LEN];

	char gbuf[MAX_EVENT_NAME_LEN];

	int ret = 0;

	int i;
@@ -869,25 +871,24 @@ static int __trace_eprobe_create(int argc, const char *argv[]) 
	event = strchr(&argv[0][1], ':');

	if (event) {

		event++;

		ret = traceprobe_parse_event_name(&event, &group, buf1,

		ret = traceprobe_parse_event_name(&event, &group, gbuf,

						  event - argv[0]);

		if (ret)

			goto parse_error;

	} else {

		strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN);

		sanitize_event_name(buf1);

		event = buf1;

	}

	if (!is_good_name(event) || !is_good_name(group))

		goto parse_error;



	trace_probe_log_set_index(1);

	sys_event = argv[1];

	ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2,

					  sys_event - argv[1]);

	if (ret || !sys_name)

	ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0);

	if (!sys_event || !sys_name)

		goto parse_error;



	if (!event) {

		strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN);

		sanitize_event_name(buf1);

		event = buf1;

	}



	mutex_lock(&event_mutex);

	event_call = find_and_get_event(sys_name, sys_event);

	ep = alloc_event_probe(group, event, event_call, argc - 2);