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@oracle.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1249497664.5890.4.camel@laptop>
[ v2: fix build error in the !CONFIG_EVENT_PROFILE case ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 5c093ff..d7cd193 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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);