diff --git a/tools/perf/trace/beauty/msg_flags.c b/tools/perf/trace/beauty/msg_flags.c
index d66c6631598783d69af5bcc62e2d9d8187bf2ed7..ea68db08b8e7195c46606381171a635582358a90 100644
--- a/tools/perf/trace/beauty/msg_flags.c
+++ b/tools/perf/trace/beauty/msg_flags.c
@@ -29,7 +29,7 @@ static size_t syscall_arg__scnprintf_msg_flags(char *bf, size_t size,
 		return scnprintf(bf, size, "NONE");
 #define	P_MSG_FLAG(n) \
 	if (flags & MSG_##n) { \
-		printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "|" : "", show_prefix ? prefix : "", #n); \
+		printed += scnprintf(bf + printed, size - printed, "%s%s%s", printed ? "|" : "", show_prefix ? prefix : "", #n); \
 		flags &= ~MSG_##n; \
 	}