tracing: Check the return value of trace_get_user()
Return immediately if trace_get_user() returned failure.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4AB86614.7020803@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index c71e91b..a8fe478 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2202,7 +2202,7 @@
struct trace_parser *parser;
ssize_t ret, read;
- if (!cnt || cnt < 0)
+ if (!cnt)
return 0;
mutex_lock(&ftrace_regex_lock);
@@ -2216,7 +2216,7 @@
parser = &iter->parser;
read = trace_get_user(parser, ubuf, cnt, ppos);
- if (trace_parser_loaded(parser) &&
+ if (read >= 0 && trace_parser_loaded(parser) &&
!trace_parser_cont(parser)) {
ret = ftrace_process_regex(parser->buffer,
parser->idx, enable);
@@ -2552,8 +2552,7 @@
size_t cnt, loff_t *ppos)
{
struct trace_parser parser;
- size_t read = 0;
- ssize_t ret;
+ ssize_t read, ret;
if (!cnt || cnt < 0)
return 0;
@@ -2572,7 +2571,7 @@
read = trace_get_user(&parser, ubuf, cnt, ppos);
- if (trace_parser_loaded((&parser))) {
+ if (read >= 0 && trace_parser_loaded((&parser))) {
parser.buffer[parser.idx] = 0;
/* we allow only one expression at a time */