Re: Latest net-next from GIT panic

[Eric Dumazet]

On Wed, 2017-09-20 at 06:34 -0700, Eric Dumazet wrote:
> Could you try this debug patch ?
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 
> f535779d9dc1dfe36934c2abba4e43d053ac5d6f..1eaa3553a724dc8c048f67b556337072d5addc82
>  100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -3331,7 +3331,14 @@ void netdev_run_todo(void);
>   */
>  static inline void dev_put(struct net_device *dev)
>  {
> -     this_cpu_dec(*dev->pcpu_refcnt);
> +     int __percpu *pref = READ_ONCE(dev->pcpu_refcnt);
> +
> +     if (!pref) {
> +             pr_err("no pcpu_refcnt on dev %p(%s) state %d dismantle %d\n",
> +                    dev, dev->name, dev->reg_state, dev->dismantle);
> +             BUG();
> +     }
> +     this_cpu_dec(*pref);
>  }
>  
>  /**
> 

And since the console will be filled by stack trace, maybe instead of
BUG() use some infinite loop ?

for (;;)
        cpu_relax();