netdev - Re: Latest net-next from GIT panic

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Message-ID: <273f49c7-58c0-0b41-10ff-6f891ffb72e9@itcare.pl>
Date:   Wed, 20 Sep 2017 17:05:43 +0200
From:   Paweł Staszewski <pstaszewski@...are.pl>
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     Wei Wang <weiwan@...gle.com>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        edumazet@...gle.com
Subject: Re: Latest net-next from GIT panic

W dniu 2017-09-20 o 16:40, Eric Dumazet pisze:
> On Wed, 2017-09-20 at 16:03 +0200, Paweł Staszewski wrote:
>> Nit much more after adding this patch
>>
>> https://bugzilla.kernel.org/attachment.cgi?id=258529
>>
> This is why I suggested to replace the BUG() in another mail
>
> So :
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index f535779d9dc1dfe36934c2abba4e43d053ac5d6f..220cd12456754876edf2d3ef13195e82d70d5c74 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -3331,7 +3331,15 @@ 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);
> +		for (;;)
> +			cpu_relax();
> +	}
> +	this_cpu_dec(*pref);
>   }
>   
>   /**
>
>
>

Full panic

https://bugzilla.kernel.org/attachment.cgi?id=258531


I will change patch and apply but later today cause now cant use backup 
router as testlab - Internet rush hours if something happens this will 
be bed when second router will have bugged kernel :)