Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 69a3fe9..a9dfa04 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -272,9 +272,11 @@
 		goto out;
 	}
 
+	mutex_lock(&event_mutex);
 	ret = perf_trace_event_init(tp_event, p_event);
 	if (ret)
 		destroy_local_trace_kprobe(tp_event);
+	mutex_unlock(&event_mutex);
 out:
 	kfree(func);
 	return ret;
@@ -282,15 +284,18 @@
 
 void perf_kprobe_destroy(struct perf_event *p_event)
 {
+	mutex_lock(&event_mutex);
 	perf_trace_event_close(p_event);
 	perf_trace_event_unreg(p_event);
+	mutex_unlock(&event_mutex);
 
 	destroy_local_trace_kprobe(p_event->tp_event);
 }
 #endif /* CONFIG_KPROBE_EVENTS */
 
 #ifdef CONFIG_UPROBE_EVENTS
-int perf_uprobe_init(struct perf_event *p_event, bool is_retprobe)
+int perf_uprobe_init(struct perf_event *p_event,
+		     unsigned long ref_ctr_offset, bool is_retprobe)
 {
 	int ret;
 	char *path = NULL;
@@ -298,22 +303,20 @@
 
 	if (!p_event->attr.uprobe_path)
 		return -EINVAL;
-	path = kzalloc(PATH_MAX, GFP_KERNEL);
-	if (!path)
-		return -ENOMEM;
-	ret = strncpy_from_user(
-		path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);
-	if (ret == PATH_MAX)
-		return -E2BIG;
-	if (ret < 0)
-		goto out;
+
+	path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path),
+			    PATH_MAX);
+	if (IS_ERR(path)) {
+		ret = PTR_ERR(path);
+		return (ret == -EINVAL) ? -E2BIG : ret;
+	}
 	if (path[0] == '\0') {
 		ret = -EINVAL;
 		goto out;
 	}
 
-	tp_event = create_local_trace_uprobe(
-		path, p_event->attr.probe_offset, is_retprobe);
+	tp_event = create_local_trace_uprobe(path, p_event->attr.probe_offset,
+					     ref_ctr_offset, is_retprobe);
 	if (IS_ERR(tp_event)) {
 		ret = PTR_ERR(tp_event);
 		goto out;
@@ -417,8 +420,7 @@
 	unsigned long flags;
 
 	local_save_flags(flags);
-	tracing_generic_entry_update(entry, flags, pc);
-	entry->type = type;
+	tracing_generic_entry_update(entry, type, flags, pc);
 }
 NOKPROBE_SYMBOL(perf_trace_buf_update);