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Subject[PATCH tracing/kprobes 1/6] tracing/kprobes: Fix trace_probe registration order
Date
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@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
---
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@redhat.com


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