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

tip-bot for Peter Zijlstra
2009-08-06T04:28:46Z

Commit-ID: af6af30c0fcd77e621638e53ef8b176bca8bd3b4
Gitweb: http://git.kernel.org/tip/af6af30c0fcd77e621638e53ef8b176bca8bd3b4
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 5 Aug 2009 20:41:04 +0200
Committer: Ingo Molnar <mingo@elte.hu>
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@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>

---
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);