1 files changed, 32 insertions, 18 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7ed6976..243f683 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -95,7 +95,7 @@ static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp)
 }
 
 static int register_probe_event(struct trace_probe *tp);
-static void unregister_probe_event(struct trace_probe *tp);
+static int unregister_probe_event(struct trace_probe *tp);
 
 static DEFINE_MUTEX(probe_lock);
 static LIST_HEAD(probe_list);
@@ -243,11 +243,11 @@ find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
 static int
 disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 {
+	struct event_file_link *link = NULL;
+	int wait = 0;
 	int ret = 0;
 
 	if (file) {
-		struct event_file_link *link;
-
 		link = find_event_file_link(tp, file);
 		if (!link) {
 			ret = -EINVAL;
@@ -255,10 +255,7 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 		}
 
 		list_del_rcu(&link->list);
-		/* synchronize with kprobe_trace_func/kretprobe_trace_func */
-		synchronize_sched();
-		kfree(link);
-
+		wait = 1;
 		if (!list_empty(&tp->files))
 			goto out;
 
@@ -271,8 +268,22 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 			disable_kretprobe(&tp->rp);
 		else
 			disable_kprobe(&tp->rp.kp);
+		wait = 1;
 	}
  out:
+	if (wait) {
+		/*
+		 * Synchronize with kprobe_trace_func/kretprobe_trace_func
+		 * to ensure disabled (all running handlers are finished).
+		 * This is not only for kfree(), but also the caller,
+		 * trace_remove_event_call() supposes it for releasing
+		 * event_call related objects, which will be accessed in
+		 * the kprobe_trace_func/kretprobe_trace_func.
+		 */
+		synchronize_sched();
+		kfree(link);	/* Ignored if link == NULL */
+	}
+
 	return ret;
 }
 
@@ -340,9 +351,12 @@ static int unregister_trace_probe(struct trace_probe *tp)
 	if (trace_probe_is_enabled(tp))
 		return -EBUSY;
 
+	/* Will fail if probe is being used by ftrace or perf */
+	if (unregister_probe_event(tp))
+		return -EBUSY;
+
 	__unregister_trace_probe(tp);
 	list_del(&tp->list);
-	unregister_probe_event(tp);
 
 	return 0;
 }
@@ -621,7 +635,9 @@ static int release_all_trace_probes(void)
 	/* TODO: Use batch unregistration */
 	while (!list_empty(&probe_list)) {
 		tp = list_entry(probe_list.next, struct trace_probe, list);
-		unregister_trace_probe(tp);
+		ret = unregister_trace_probe(tp);
+		if (ret)
+			goto end;
 		free_trace_probe(tp);
 	}
 
@@ -1087,9 +1103,6 @@ kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs)
 	__size = sizeof(*entry) + tp->size + dsize;
 	size = ALIGN(__size + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		     "profile buffer not large enough"))
-		return;
 
 	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
 	if (!entry)
@@ -1120,9 +1133,6 @@ kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri,
 	__size = sizeof(*entry) + tp->size + dsize;
 	size = ALIGN(__size + sizeof(u32), sizeof(u64));
 	size -= sizeof(u32);
-	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		     "profile buffer not large enough"))
-		return;
 
 	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
 	if (!entry)
@@ -1242,11 +1252,15 @@ static int register_probe_event(struct trace_probe *tp)
 	return ret;
 }
 
-static void unregister_probe_event(struct trace_probe *tp)
+static int unregister_probe_event(struct trace_probe *tp)
 {
+	int ret;
+
 	/* tp->event is unregistered in trace_remove_event_call() */
-	trace_remove_event_call(&tp->call);
-	kfree(tp->call.print_fmt);
+	ret = trace_remove_event_call(&tp->call);
+	if (!ret)
+		kfree(tp->call.print_fmt);
+	return ret;
 }
 
 /* Make a debugfs interface for controlling probe points */