[PATCH 4.9 68/84] binder: use group leader instead of open thread

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Todd Kjos <tkjos@xxxxxxxxxxx>

commit c4ea41ba195d01c9af66fb28711a16cc97caa9c5 upstream.

The binder allocator assumes that the thread that
called binder_open will never die for the lifetime of
that proc. That thread is normally the group_leader,
however it may not be. Use the group_leader instead
of current.

Signed-off-by: Todd Kjos <tkjos@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/android/binder.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2972,8 +2972,8 @@ static int binder_open(struct inode *nod
 	proc = kzalloc(sizeof(*proc), GFP_KERNEL);
 	if (proc == NULL)
 		return -ENOMEM;
-	get_task_struct(current);
-	proc->tsk = current;
+	get_task_struct(current->group_leader);
+	proc->tsk = current->group_leader;
 	INIT_LIST_HEAD(&proc->todo);
 	init_waitqueue_head(&proc->wait);
 	proc->default_priority = task_nice(current);