Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/perf/util/symbol_fprintf.c b/tools/perf/util/symbol_fprintf.c
index ed0205c..35c936c 100644
--- a/tools/perf/util/symbol_fprintf.c
+++ b/tools/perf/util/symbol_fprintf.c
@@ -3,6 +3,8 @@
 #include <inttypes.h>
 #include <stdio.h>
 
+#include "dso.h"
+#include "map.h"
 #include "symbol.h"
 
 size_t symbol__fprintf(struct symbol *sym, FILE *fp)
@@ -64,7 +66,7 @@
 	struct rb_node *nd;
 	struct symbol_name_rb_node *pos;
 
-	for (nd = rb_first(&dso->symbol_names); nd; nd = rb_next(nd)) {
+	for (nd = rb_first_cached(&dso->symbol_names); nd; nd = rb_next(nd)) {
 		pos = rb_entry(nd, struct symbol_name_rb_node, rb_node);
 		fprintf(fp, "%s\n", pos->sym.name);
 	}