From: Ian Munsie <[email protected]>
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 <[email protected]>
---
kernel/trace/trace_syscalls.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 85983fd..6e17886 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -80,6 +80,9 @@ static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
stop = (struct syscall_metadata *)__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;
--
1.7.2.3