tracing/kprobes: Fix trace_probe registration order

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

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
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: 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: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090914204856.18779.52961.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 19 insertions, 23 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index cbc0870dcf5d..ea0db8eee570 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;