tracing: Make sure the parsed string always terminates with '\0'

Always mark the parsed string with a terminated nul '\0' character. This removes
the need for the users to have to append the '\0' before using the parsed string.

Link: http://lkml.kernel.org/r/1516093350-12045-4-git-send-email-changbin.du@intel.com

Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index cb90435e63da..58de825df19c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -530,8 +530,6 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
                 ubuf += ret;
                 cnt -= ret;
 
-                parser.buffer[parser.idx] = 0;
-
                 ret = -EINVAL;
                 if (kstrtoul(parser.buffer, 0, &val))
                         break;
@@ -1268,6 +1266,8 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
         } else if (parser->idx < parser->size - 1) {
                 parser->cont = true;
                 parser->buffer[parser->idx++] = ch;
+                /* Make sure the parsed string always terminates with '\0'. */
+                parser->buffer[parser->idx] = 0;
         } else {
                 ret = -EINVAL;
                 goto out;