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From: Michal Kubecek <mkubecek@suse.cz>
To: netdev@vger.kernel.org
Cc: Saeed Mahameed <saeedm@mellanox.com>,
	"liudongxu3@huawei.com" <liudongxu3@huawei.com>,
	"eric.dumazet@gmail.com" <eric.dumazet@gmail.com>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] net: Adding parameter detection in __ethtool_get_link_ksettings.
Date: Thu, 29 Aug 2019 08:01:38 +0200	[thread overview]
Message-ID: <20190829060138.GL29594@unicorn.suse.cz> (raw)
In-Reply-To: <0db9e18a4dd81d9a6025a2d8cda343b585d91fc4.camel@mellanox.com>

On Tue, Aug 27, 2019 at 07:01:41PM +0000, Saeed Mahameed wrote:
> On Mon, 2019-08-26 at 17:47 +0800, Dongxu Liu wrote:
> 
> > Maybe "if (!dev->ethtool_ops)" is more accurate for this bug.
> > 
> 
> Also i am not sure about this, could be a bug in the device driver your
> enslaving.
> 
> alloc_netdev_mqs will assign &default_ethtool_ops to dev->ethtool_ops ,
> if user provided setup callback didn't assign the driver specific
> ethtool_ops.

Dongxu said he encountered the null pointer dereference in a 3.10
kernel, not current mainline. But commit 2c60db037034 ("net: provide a
default dev->ethtool_ops") which introduced default_ethtool_ops came in
3.7-rc1 so 3.10 should have it already. There is indeed something wrong.

I don't think we should add either check unless we positively know that
dev->ethtool_ops can be null with current mainline kernel. And even
then, it would probably be more appropriate to fix the code which caused
it.

Michal

      reply	other threads:[~2019-08-29  6:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-26  7:23 [PATCH] net: Adding parameter detection in __ethtool_get_link_ksettings Dongxu Liu
2019-08-26  8:16 ` Eric Dumazet
2019-08-26  9:47   ` Dongxu Liu
2019-08-27 19:01     ` Saeed Mahameed
2019-08-29  6:01       ` Michal Kubecek [this message]

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