[tip:perfcounters/urgent] ftrace: Fix perf-tracepoint OOPS

[tip-bot for Peter Zijlstra]

Commit-ID:  af6af30c0fcd77e621638e53ef8b176bca8bd3b4
Gitweb:     http://git.kernel.org/tip/af6af30c0fcd77e621638e53ef8b176bca8bd3b4
Author:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 5 Aug 2009 20:41:04 +0200
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 6 Aug 2009 06:26:09 +0200

ftrace: Fix perf-tracepoint OOPS

Not all tracepoints are created equal, in specific the ftrace
tracepoints are created with TRACE_EVENT_FORMAT() which does
not generate the needed bits to tie them into perf counters.

For those events, don't create the 'id' file and fail
->profile_enable when their ID is specified through other
means.

Reported-by: Chris Mason <chris.mason@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
LKML-Reference: <1249497664.5890.4.camel@laptop>
[ v2: fix build error in the !CONFIG_EVENT_PROFILE case ]
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
 include/linux/ftrace_event.h       |    8 +++-----
 kernel/trace/trace_event_profile.c |    2 +-
 kernel/trace/trace_events.c        |    2 +-
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 5c093ff..d7cd193 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -119,11 +119,9 @@ struct ftrace_event_call {
 	void			*filter;
 	void			*mod;
 
-#ifdef CONFIG_EVENT_PROFILE
-	atomic_t	profile_count;
-	int		(*profile_enable)(struct ftrace_event_call *);
-	void		(*profile_disable)(struct ftrace_event_call *);
-#endif
+	atomic_t		profile_count;
+	int			(*profile_enable)(struct ftrace_event_call *);
+	void			(*profile_disable)(struct ftrace_event_call *);
 };
 
 #define MAX_FILTER_PRED		32
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
index 5b5895a..11ba5bb 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -14,7 +14,7 @@ int ftrace_profile_enable(int event_id)
 
 	mutex_lock(&event_mutex);
 	list_for_each_entry(event, &ftrace_events, list) {
-		if (event->id == event_id) {
+		if (event->id == event_id && event->profile_enable) {
 			ret = event->profile_enable(event);
 			break;
 		}
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 23d2972..e75276a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -940,7 +940,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 		entry = trace_create_file("enable", 0644, call->dir, call,
 					  enable);
 
-	if (call->id)
+	if (call->id && call->profile_enable)
 		entry = trace_create_file("id", 0444, call->dir, call,
 					  id);
 
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