From: Taehee Yoo <ap420...@gmail.com>
Date: Wed, 17 Oct 2018 00:35:10 +0900
> pid_task() dereferences rcu protected tasks array.
> But there is no rcu_read_lock() in shutdown_umh() routine so that
> rcu_read_lock() is needed.
> get_pid_task() is wrapper function of pid_task. it holds rcu_read_lock()
> then calls pid_task(). if task isn't NULL, it increases reference count
> of task.
>
> test commands:
> %modprobe bpfilter
> %modprobe -rv bpfilter
...
> Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module")
> Signed-off-by: Taehee Yoo <ap420...@gmail.com>
Applied and queued up for -stable, thanks.
