binder: use group leader instead of open thread

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@google.com>
Cc: stable <stable@vger.kernel.org> # 4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 157bd3e49ff4ab423361fd5a3faa6e30559c896c..9393924ae8e862554aec5d0c5eba1083e20644c6 100644 (file)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3460,8 +3460,8 @@ static int binder_open(struct inode *nodp, struct file *filp)
        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);