From ae07f551c42d6e4162436ca452a199deac9dab4d Mon Sep 17 00:00:00 2001
From: Ian Munsie <imunsie@au1.ibm.com>
Date: Thu, 3 Feb 2011 14:27:25 +1100
Subject: [PATCH] tracing/syscalls: Early terminate search for sys_ni_syscall
Many system calls are unimplemented and mapped to sys_ni_syscall, but at
boot ftrace would still search through every syscall metadata entry for
a match which wouldn't be there.
This patch adds causes the search to terminate early if the system call
is not mapped.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
LKML-Reference: <1296703645-18718-7-git-send-email-imunsie@au1.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_syscalls.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 86a23e7de031..ee7b5a0bb9f8 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -85,6 +85,9 @@ find_syscall_meta(unsigned long syscall)
stop = __stop_syscalls_metadata;
kallsyms_lookup(syscall, NULL, NULL, NULL, str);
+ if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
+ return NULL;
+
for ( ; start < stop; start++) {
if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
return *start;
--
GitLab