ftrace: Call trace_parser_clear() properly

I found a weird behavior:

  # echo 'fuse:*' > set_ftrace_filter
  bash: echo: write error: Invalid argument
  # cat set_ftrace_filter
  fuse_dev_fasync
  fuse_dev_poll
  fuse_copy_do

We should call trace_parser_clear() no matter ftrace_process_regex()
returns 0 or -errno, otherwise we will actually take the unaccepted
records from ftrace_regex_release().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B1DC4D2.3000406@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 08a3fb5b3187..ff8aecdc6dd6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2208,10 +2208,9 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
             !trace_parser_cont(parser)) {
                 ret = ftrace_process_regex(parser->buffer,
                                            parser->idx, enable);
+                trace_parser_clear(parser);
                 if (ret)
                         goto out_unlock;
-
-                trace_parser_clear(parser);
         }
 
         ret = read;