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/trace_events.c b/kernel/trace/trace_events.c
index 6f03c8a..d128f65 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -232,10 +232,9 @@
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)
+ if (!cnt)
return 0;
ret = tracing_update_buffers();
@@ -247,7 +246,7 @@
read = trace_get_user(&parser, ubuf, cnt, ppos);
- if (trace_parser_loaded((&parser))) {
+ if (read >= 0 && trace_parser_loaded((&parser))) {
int set = 1;
if (*parser.buffer == '!')