[PATCH][v3] rtnetlink: add rtnl_lock debug log

[Cong Wang]

On Tue, May 11, 2021 at 4:46 AM Rocco yue <rocco.yue at mediatek.com> wrote:
>
> From: Rocco Yue <rocco.yue at mediatek.com>
>
> We often encounter system hangs caused by certain process
> holding rtnl_lock for a long time. Even if there is a lock
> detection mechanism in Linux, it is a bit troublesome and
> affects the system performance. We hope to add a lightweight
> debugging mechanism for detecting rtnl_lock.

Any reason why this is specific to RTNL lock? To me holding
a mutex lock for a long time is problematic for any mutex.
I have seen some fs mutex being held for a long time caused
many hung tasks in the system.

Thanks.