[PATCH 4.12 85/99] binder: use group leader instead of open thread

Greg Kroah-Hartman
2017-08-28T09:05:45Z

From: Todd Kjos <tkjos@android.com>

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@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3460,8 +3460,8 @@ 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);