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

From: tip-bot for Peter Zijlstra
Date: Wed Aug 05 2009 - 14:49:34 EST


Commit-ID: 5fe31b14cc8eccc06311c3cc5674420a66431372
Gitweb: http://git.kernel.org/tip/5fe31b14cc8eccc06311c3cc5674420a66431372
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 5 Aug 2009 20:41:04 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 5 Aug 2009 20:45:52 +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>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
kernel/trace/trace_event_profile.c | 2 +-
kernel/trace/trace_events.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

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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