[PATCH 4.19 29/44] tracing: Fix memory leak of instance function hash filters

Greg Kroah-Hartman
2018-12-18T16:42:57Z

From: Steven Rostedt (VMware) <rostedt@goodmis.org>

commit 2840f84f74035e5a535959d5f17269c69fa6edc5 upstream.

The following commands will cause a memory leak:

# cd /sys/kernel/tracing
# mkdir instances/foo
# echo schedule > instance/foo/set_ftrace_filter
# rmdir instances/foo

The reason is that the hashes that hold the filters to set_ftrace_filter and
set_ftrace_notrace are not freed if they contain any data on the instance
and the instance is removed.

Found by kmemleak detector.

Cc: stable@vger.kernel.org
Fixes: 591dffdade9f ("ftrace: Allow for function tracing instance to filter functions")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/trace/ftrace.c | 1 +
1 file changed, 1 insertion(+)

--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5460,6 +5460,7 @@ void ftrace_destroy_filter_files(struct
if (ops->flags & FTRACE_OPS_FL_ENABLED)
ftrace_shutdown(ops, 0);
ops->flags |= FTRACE_OPS_FL_DELETED;
+ ftrace_free_filter(ops);
mutex_unlock(&ftrace_lock);
}