trace_stack: Fix seqfile memory leak

Every time we cat stack_trace, we leak memory allocated by seq_open().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A67D8E8.3020500@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
1 file changed