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Commit 9b63776f authored May 10, 2012 by Steven Rostedt Committed by Steven Rostedt May 10, 2012

tracing: Do not enable function event with enable



With the adding of function tracing event to perf, it caused a
side effect that produces the following warning when enabling all
events in ftrace:

 # echo 1 > /sys/kernel/debug/tracing/events/enable

[console]
event trace: Could not enable event function

This is because when enabling all events via the debugfs system
it ignores events that do not have a ->reg() function assigned.
This was to skip over the ftrace internal events (as they are
not TRACE_EVENTs). But as the ftrace function event now has
a ->reg() function attached to it for use with perf, it is no
longer ignored.

Worse yet, this ->reg() function is being called when it should
not be. It returns an error and causes the above warning to
be printed.

By adding a new event_call flag (TRACE_EVENT_FL_IGNORE_ENABLE)
and have all ftrace internel event structures have it set,
setting the events/enable will no longe try to incorrectly enable
the function event and does not warn.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

parent 20d23aaa

include/linux/ftrace_event.h

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -179,6 +179,7 @@ enum {
	TRACE_EVENT_FL_RECORDED_CMD_BIT,		TRACE_EVENT_FL_RECORDED_CMD_BIT,
	TRACE_EVENT_FL_CAP_ANY_BIT,		TRACE_EVENT_FL_CAP_ANY_BIT,
	TRACE_EVENT_FL_NO_SET_FILTER_BIT,		TRACE_EVENT_FL_NO_SET_FILTER_BIT,
			TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
	};		};

	enum {		enum {
	@@ -187,6 +188,7 @@ enum {
	TRACE_EVENT_FL_RECORDED_CMD = (1 << TRACE_EVENT_FL_RECORDED_CMD_BIT),		TRACE_EVENT_FL_RECORDED_CMD = (1 << TRACE_EVENT_FL_RECORDED_CMD_BIT),
	TRACE_EVENT_FL_CAP_ANY = (1 << TRACE_EVENT_FL_CAP_ANY_BIT),		TRACE_EVENT_FL_CAP_ANY = (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
	TRACE_EVENT_FL_NO_SET_FILTER = (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),		TRACE_EVENT_FL_NO_SET_FILTER = (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
			TRACE_EVENT_FL_IGNORE_ENABLE = (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
	};		};

	struct ftrace_event_call {		struct ftrace_event_call {

kernel/trace/trace_events.c

+4 −1

Original line number	Original line	Diff line number	Diff line
	@@ -294,6 +294,9 @@ static int __ftrace_set_clr_event(const char match, const char sub,
	if (!call->name \|\| !call->class \|\| !call->class->reg)		if (!call->name \|\| !call->class \|\| !call->class->reg)
	continue;		continue;

			if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
			continue;

	if (match &&		if (match &&
	strcmp(match, call->name) != 0 &&		strcmp(match, call->name) != 0 &&
	strcmp(match, call->class->system) != 0)		strcmp(match, call->class->system) != 0)
	@@ -1164,7 +1167,7 @@ event_create_dir(struct ftrace_event_call call, struct dentry d_events,
	return -1;		return -1;
	}		}

	if (call->class->reg)		if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
	trace_create_file("enable", 0644, call->dir, call,		trace_create_file("enable", 0644, call->dir, call,
	enable);		enable);

kernel/trace/trace_export.c

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -180,6 +180,7 @@ struct ftrace_event_call __used event_##call = { \
	.event.type = etype, \		.event.type = etype, \
	.class = &event_class_ftrace_##call, \		.class = &event_class_ftrace_##call, \
	.print_fmt = print, \		.print_fmt = print, \
			.flags = TRACE_EVENT_FL_IGNORE_ENABLE, \
	}; \		}; \
	struct ftrace_event_call __used \		struct ftrace_event_call __used \
	__attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;		__attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;