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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>
This commit is contained in:
Steven Rostedt 2012-05-10 15:55:43 -04:00 committed by Steven Rostedt
parent 20d23aaa31
commit 9b63776fa3
3 changed files with 7 additions and 1 deletions
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2
include/linux/ftrace_event.h
View File

@ -179,6 +179,7 @@ enum {
TRACE_EVENT_FL_RECORDED_CMD_BIT,
TRACE_EVENT_FL_CAP_ANY_BIT,
TRACE_EVENT_FL_NO_SET_FILTER_BIT,
TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
};
enum {
@ -187,6 +188,7 @@ enum {
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_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 {

5
kernel/trace/trace_events.c
View File

@ -294,6 +294,9 @@ static int __ftrace_set_clr_event(const char *match, const char *sub,
if (!call->name || !call->class || !call->class->reg)
continue;
if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
continue;
if (match &&
strcmp(match, call->name) != 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;
}
if (call->class->reg)
if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
trace_create_file("enable", 0644, call->dir, call,
enable);

1
kernel/trace/trace_export.c
View File

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