[PATCH tracing/kprobes 1/6] tracing/kprobes: Fix trace_proberegistration order

[Masami Hiramatsu]

Fix trace_probe registration order. ftrace_event_call and ftrace_event
must be registered before kprobe/kretprobe, because tracing/profiling
handlers use event-id.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Jim Keniston <jkenisto@xxxxxxxxxx>
Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Frank Ch. Eigler <fche@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: K.Prasad <prasad@xxxxxxxxxxxxxxxxxx>
Cc: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Tom Zanussi <tzanussi@xxxxxxxxx>
---

 kernel/trace/trace_kprobe.c |   42 +++++++++++++++++++-----------------------
 1 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index cbc0870..ea0db8e 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -347,20 +347,15 @@ static struct trace_probe *find_probe_event(const char *event)
 	return NULL;
 }
 
-static void __unregister_trace_probe(struct trace_probe *tp)
+/* Unregister a trace_probe and probe_event: call with locking probe_lock */
+static void unregister_trace_probe(struct trace_probe *tp)
 {
 	if (probe_is_return(tp))
 		unregister_kretprobe(&tp->rp);
 	else
 		unregister_kprobe(&tp->rp.kp);
-}
-
-/* Unregister a trace_probe and probe_event: call with locking probe_lock */
-static void unregister_trace_probe(struct trace_probe *tp)
-{
-	unregister_probe_event(tp);
-	__unregister_trace_probe(tp);
 	list_del(&tp->list);
+	unregister_probe_event(tp);
 }
 
 /* Register a trace_probe and probe_event */
@@ -371,6 +366,19 @@ static int register_trace_probe(struct trace_probe *tp)
 
 	mutex_lock(&probe_lock);
 
+	/* register as an event */
+	old_tp = find_probe_event(tp->call.name);
+	if (old_tp) {
+		/* delete old event */
+		unregister_trace_probe(old_tp);
+		free_trace_probe(old_tp);
+	}
+	ret = register_probe_event(tp);
+	if (ret) {
+		pr_warning("Faild to register probe event(%d)\n", ret);
+		goto end;
+	}
+
 	if (probe_is_return(tp))
 		ret = register_kretprobe(&tp->rp);
 	else
@@ -384,21 +392,9 @@ static int register_trace_probe(struct trace_probe *tp)
 				   tp->rp.kp.addr);
 			ret = -EINVAL;
 		}
-		goto end;
-	}
-	/* register as an event */
-	old_tp = find_probe_event(tp->call.name);
-	if (old_tp) {
-		/* delete old event */
-		unregister_trace_probe(old_tp);
-		free_trace_probe(old_tp);
-	}
-	ret = register_probe_event(tp);
-	if (ret) {
-		pr_warning("Faild to register probe event(%d)\n", ret);
-		__unregister_trace_probe(tp);
-	}
-	list_add_tail(&tp->list, &probe_list);
+		unregister_probe_event(tp);
+	} else
+		list_add_tail(&tp->list, &probe_list);
 end:
 	mutex_unlock(&probe_lock);
 	return ret;


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx
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